1 /*
2  * copyright (c) 2001 Fabrice Bellard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVCODEC_AVCODEC_H
22 #define AVCODEC_AVCODEC_H
23 
24 /**
25  * @file
26  * @ingroup libavc
27  * Libavcodec external API header
28  */
29 
30 #include <errno.h>
31 #include "libavutil/samplefmt.h"
32 #include "libavutil/attributes.h"
33 #include "libavutil/avutil.h"
34 #include "libavutil/buffer.h"
35 #include "libavutil/cpu.h"
36 #include "libavutil/channel_layout.h"
37 #include "libavutil/dict.h"
38 #include "libavutil/frame.h"
39 #include "libavutil/log.h"
40 #include "libavutil/pixfmt.h"
41 #include "libavutil/rational.h"
42 
43 #include "version.h"
44 
45 #if FF_API_FAST_MALLOC
46 // to provide fast_*alloc
47 #include "libavutil/mem.h"
48 #endif
49 
50 /**
51  * @defgroup libavc Encoding/Decoding Library
52  * @{
53  *
54  * @defgroup lavc_decoding Decoding
55  * @{
56  * @}
57  *
58  * @defgroup lavc_encoding Encoding
59  * @{
60  * @}
61  *
62  * @defgroup lavc_codec Codecs
63  * @{
64  * @defgroup lavc_codec_native Native Codecs
65  * @{
66  * @}
67  * @defgroup lavc_codec_wrappers External library wrappers
68  * @{
69  * @}
70  * @defgroup lavc_codec_hwaccel Hardware Accelerators bridge
71  * @{
72  * @}
73  * @}
74  * @defgroup lavc_internal Internal
75  * @{
76  * @}
77  * @}
78  *
79  */
80 
81 /**
82  * @defgroup lavc_core Core functions/structures.
83  * @ingroup libavc
84  *
85  * Basic definitions, functions for querying libavcodec capabilities,
86  * allocating core structures, etc.
87  * @{
88  */
89 
90 
91 /**
92  * Identify the syntax and semantics of the bitstream.
93  * The principle is roughly:
94  * Two decoders with the same ID can decode the same streams.
95  * Two encoders with the same ID can encode compatible streams.
96  * There may be slight deviations from the principle due to implementation
97  * details.
98  *
99  * If you add a codec ID to this list, add it so that
100  * 1. no value of a existing codec ID changes (that would break ABI),
101  * 2. Give it a value which when taken as ASCII is recognized uniquely by a human as this specific codec.
102  *    This ensures that 2 forks can independently add AVCodecIDs without producing conflicts.
103  *
104  * After adding new codec IDs, do not forget to add an entry to the codec
105  * descriptor list and bump libavcodec minor version.
106  */
107 enum AVCodecID {
108     AV_CODEC_ID_NONE,
109 
110     /* video codecs */
111     AV_CODEC_ID_MPEG1VIDEO,
112     AV_CODEC_ID_MPEG2VIDEO, ///< preferred ID for MPEG-1/2 video decoding
113 #if FF_API_XVMC
114     AV_CODEC_ID_MPEG2VIDEO_XVMC,
115 #endif /* FF_API_XVMC */
116     AV_CODEC_ID_H261,
117     AV_CODEC_ID_H263,
118     AV_CODEC_ID_RV10,
119     AV_CODEC_ID_RV20,
120     AV_CODEC_ID_MJPEG,
121     AV_CODEC_ID_MJPEGB,
122     AV_CODEC_ID_LJPEG,
123     AV_CODEC_ID_SP5X,
124     AV_CODEC_ID_JPEGLS,
125     AV_CODEC_ID_MPEG4,
126     AV_CODEC_ID_RAWVIDEO,
127     AV_CODEC_ID_MSMPEG4V1,
128     AV_CODEC_ID_MSMPEG4V2,
129     AV_CODEC_ID_MSMPEG4V3,
130     AV_CODEC_ID_WMV1,
131     AV_CODEC_ID_WMV2,
132     AV_CODEC_ID_H263P,
133     AV_CODEC_ID_H263I,
134     AV_CODEC_ID_FLV1,
135     AV_CODEC_ID_SVQ1,
136     AV_CODEC_ID_SVQ3,
137     AV_CODEC_ID_DVVIDEO,
138     AV_CODEC_ID_HUFFYUV,
139     AV_CODEC_ID_CYUV,
140     AV_CODEC_ID_H264,
141     AV_CODEC_ID_INDEO3,
142     AV_CODEC_ID_VP3,
143     AV_CODEC_ID_THEORA,
144     AV_CODEC_ID_ASV1,
145     AV_CODEC_ID_ASV2,
146     AV_CODEC_ID_FFV1,
147     AV_CODEC_ID_4XM,
148     AV_CODEC_ID_VCR1,
149     AV_CODEC_ID_CLJR,
150     AV_CODEC_ID_MDEC,
151     AV_CODEC_ID_ROQ,
152     AV_CODEC_ID_INTERPLAY_VIDEO,
153     AV_CODEC_ID_XAN_WC3,
154     AV_CODEC_ID_XAN_WC4,
155     AV_CODEC_ID_RPZA,
156     AV_CODEC_ID_CINEPAK,
157     AV_CODEC_ID_WS_VQA,
158     AV_CODEC_ID_MSRLE,
159     AV_CODEC_ID_MSVIDEO1,
160     AV_CODEC_ID_IDCIN,
161     AV_CODEC_ID_8BPS,
162     AV_CODEC_ID_SMC,
163     AV_CODEC_ID_FLIC,
164     AV_CODEC_ID_TRUEMOTION1,
165     AV_CODEC_ID_VMDVIDEO,
166     AV_CODEC_ID_MSZH,
167     AV_CODEC_ID_ZLIB,
168     AV_CODEC_ID_QTRLE,
169     AV_CODEC_ID_TSCC,
170     AV_CODEC_ID_ULTI,
171     AV_CODEC_ID_QDRAW,
172     AV_CODEC_ID_VIXL,
173     AV_CODEC_ID_QPEG,
174     AV_CODEC_ID_PNG,
175     AV_CODEC_ID_PPM,
176     AV_CODEC_ID_PBM,
177     AV_CODEC_ID_PGM,
178     AV_CODEC_ID_PGMYUV,
179     AV_CODEC_ID_PAM,
180     AV_CODEC_ID_FFVHUFF,
181     AV_CODEC_ID_RV30,
182     AV_CODEC_ID_RV40,
183     AV_CODEC_ID_VC1,
184     AV_CODEC_ID_WMV3,
185     AV_CODEC_ID_LOCO,
186     AV_CODEC_ID_WNV1,
187     AV_CODEC_ID_AASC,
188     AV_CODEC_ID_INDEO2,
189     AV_CODEC_ID_FRAPS,
190     AV_CODEC_ID_TRUEMOTION2,
191     AV_CODEC_ID_BMP,
192     AV_CODEC_ID_CSCD,
193     AV_CODEC_ID_MMVIDEO,
194     AV_CODEC_ID_ZMBV,
195     AV_CODEC_ID_AVS,
196     AV_CODEC_ID_SMACKVIDEO,
197     AV_CODEC_ID_NUV,
198     AV_CODEC_ID_KMVC,
199     AV_CODEC_ID_FLASHSV,
200     AV_CODEC_ID_CAVS,
201     AV_CODEC_ID_JPEG2000,
202     AV_CODEC_ID_VMNC,
203     AV_CODEC_ID_VP5,
204     AV_CODEC_ID_VP6,
205     AV_CODEC_ID_VP6F,
206     AV_CODEC_ID_TARGA,
207     AV_CODEC_ID_DSICINVIDEO,
208     AV_CODEC_ID_TIERTEXSEQVIDEO,
209     AV_CODEC_ID_TIFF,
210     AV_CODEC_ID_GIF,
211     AV_CODEC_ID_DXA,
212     AV_CODEC_ID_DNXHD,
213     AV_CODEC_ID_THP,
214     AV_CODEC_ID_SGI,
215     AV_CODEC_ID_C93,
216     AV_CODEC_ID_BETHSOFTVID,
217     AV_CODEC_ID_PTX,
218     AV_CODEC_ID_TXD,
219     AV_CODEC_ID_VP6A,
220     AV_CODEC_ID_AMV,
221     AV_CODEC_ID_VB,
222     AV_CODEC_ID_PCX,
223     AV_CODEC_ID_SUNRAST,
224     AV_CODEC_ID_INDEO4,
225     AV_CODEC_ID_INDEO5,
226     AV_CODEC_ID_MIMIC,
227     AV_CODEC_ID_RL2,
228     AV_CODEC_ID_ESCAPE124,
229     AV_CODEC_ID_DIRAC,
230     AV_CODEC_ID_BFI,
231     AV_CODEC_ID_CMV,
232     AV_CODEC_ID_MOTIONPIXELS,
233     AV_CODEC_ID_TGV,
234     AV_CODEC_ID_TGQ,
235     AV_CODEC_ID_TQI,
236     AV_CODEC_ID_AURA,
237     AV_CODEC_ID_AURA2,
238     AV_CODEC_ID_V210X,
239     AV_CODEC_ID_TMV,
240     AV_CODEC_ID_V210,
241     AV_CODEC_ID_DPX,
242     AV_CODEC_ID_MAD,
243     AV_CODEC_ID_FRWU,
244     AV_CODEC_ID_FLASHSV2,
245     AV_CODEC_ID_CDGRAPHICS,
246     AV_CODEC_ID_R210,
247     AV_CODEC_ID_ANM,
248     AV_CODEC_ID_BINKVIDEO,
249     AV_CODEC_ID_IFF_ILBM,
250     AV_CODEC_ID_IFF_BYTERUN1,
251     AV_CODEC_ID_KGV1,
252     AV_CODEC_ID_YOP,
253     AV_CODEC_ID_VP8,
254     AV_CODEC_ID_PICTOR,
255     AV_CODEC_ID_ANSI,
256     AV_CODEC_ID_A64_MULTI,
257     AV_CODEC_ID_A64_MULTI5,
258     AV_CODEC_ID_R10K,
259     AV_CODEC_ID_MXPEG,
260     AV_CODEC_ID_LAGARITH,
261     AV_CODEC_ID_PRORES,
262     AV_CODEC_ID_JV,
263     AV_CODEC_ID_DFA,
264     AV_CODEC_ID_WMV3IMAGE,
265     AV_CODEC_ID_VC1IMAGE,
266     AV_CODEC_ID_UTVIDEO,
267     AV_CODEC_ID_BMV_VIDEO,
268     AV_CODEC_ID_VBLE,
269     AV_CODEC_ID_DXTORY,
270     AV_CODEC_ID_V410,
271     AV_CODEC_ID_XWD,
272     AV_CODEC_ID_CDXL,
273     AV_CODEC_ID_XBM,
274     AV_CODEC_ID_ZEROCODEC,
275     AV_CODEC_ID_MSS1,
276     AV_CODEC_ID_MSA1,
277     AV_CODEC_ID_TSCC2,
278     AV_CODEC_ID_MTS2,
279     AV_CODEC_ID_CLLC,
280     AV_CODEC_ID_MSS2,
281     AV_CODEC_ID_VP9,
282     AV_CODEC_ID_AIC,
283     AV_CODEC_ID_ESCAPE130_DEPRECATED,
284     AV_CODEC_ID_G2M_DEPRECATED,
285     AV_CODEC_ID_WEBP_DEPRECATED,
286     AV_CODEC_ID_HNM4_VIDEO,
287     AV_CODEC_ID_HEVC_DEPRECATED,
288     AV_CODEC_ID_FIC,
289     AV_CODEC_ID_ALIAS_PIX,
290     AV_CODEC_ID_BRENDER_PIX_DEPRECATED,
291     AV_CODEC_ID_PAF_VIDEO_DEPRECATED,
292     AV_CODEC_ID_EXR_DEPRECATED,
293     AV_CODEC_ID_VP7_DEPRECATED,
294     AV_CODEC_ID_SANM_DEPRECATED,
295     AV_CODEC_ID_SGIRLE_DEPRECATED,
296     AV_CODEC_ID_MVC1_DEPRECATED,
297     AV_CODEC_ID_MVC2_DEPRECATED,
298 
299     AV_CODEC_ID_BRENDER_PIX= MKBETAG('B','P','I','X'),
300     AV_CODEC_ID_Y41P       = MKBETAG('Y','4','1','P'),
301     AV_CODEC_ID_ESCAPE130  = MKBETAG('E','1','3','0'),
302     AV_CODEC_ID_EXR        = MKBETAG('0','E','X','R'),
303     AV_CODEC_ID_AVRP       = MKBETAG('A','V','R','P'),
304 
305     AV_CODEC_ID_012V       = MKBETAG('0','1','2','V'),
306     AV_CODEC_ID_G2M        = MKBETAG( 0 ,'G','2','M'),
307     AV_CODEC_ID_AVUI       = MKBETAG('A','V','U','I'),
308     AV_CODEC_ID_AYUV       = MKBETAG('A','Y','U','V'),
309     AV_CODEC_ID_TARGA_Y216 = MKBETAG('T','2','1','6'),
310     AV_CODEC_ID_V308       = MKBETAG('V','3','0','8'),
311     AV_CODEC_ID_V408       = MKBETAG('V','4','0','8'),
312     AV_CODEC_ID_YUV4       = MKBETAG('Y','U','V','4'),
313     AV_CODEC_ID_SANM       = MKBETAG('S','A','N','M'),
314     AV_CODEC_ID_PAF_VIDEO  = MKBETAG('P','A','F','V'),
315     AV_CODEC_ID_AVRN       = MKBETAG('A','V','R','n'),
316     AV_CODEC_ID_CPIA       = MKBETAG('C','P','I','A'),
317     AV_CODEC_ID_XFACE      = MKBETAG('X','F','A','C'),
318     AV_CODEC_ID_SGIRLE     = MKBETAG('S','G','I','R'),
319     AV_CODEC_ID_MVC1       = MKBETAG('M','V','C','1'),
320     AV_CODEC_ID_MVC2       = MKBETAG('M','V','C','2'),
321     AV_CODEC_ID_SNOW       = MKBETAG('S','N','O','W'),
322     AV_CODEC_ID_WEBP       = MKBETAG('W','E','B','P'),
323     AV_CODEC_ID_SMVJPEG    = MKBETAG('S','M','V','J'),
324     AV_CODEC_ID_HEVC       = MKBETAG('H','2','6','5'),
325 #define AV_CODEC_ID_H265 AV_CODEC_ID_HEVC
326     AV_CODEC_ID_VP7        = MKBETAG('V','P','7','0'),
327 
328     /* various PCM "codecs" */
329     AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
330     AV_CODEC_ID_PCM_S16LE = 0x10000,
331     AV_CODEC_ID_PCM_S16BE,
332     AV_CODEC_ID_PCM_U16LE,
333     AV_CODEC_ID_PCM_U16BE,
334     AV_CODEC_ID_PCM_S8,
335     AV_CODEC_ID_PCM_U8,
336     AV_CODEC_ID_PCM_MULAW,
337     AV_CODEC_ID_PCM_ALAW,
338     AV_CODEC_ID_PCM_S32LE,
339     AV_CODEC_ID_PCM_S32BE,
340     AV_CODEC_ID_PCM_U32LE,
341     AV_CODEC_ID_PCM_U32BE,
342     AV_CODEC_ID_PCM_S24LE,
343     AV_CODEC_ID_PCM_S24BE,
344     AV_CODEC_ID_PCM_U24LE,
345     AV_CODEC_ID_PCM_U24BE,
346     AV_CODEC_ID_PCM_S24DAUD,
347     AV_CODEC_ID_PCM_ZORK,
348     AV_CODEC_ID_PCM_S16LE_PLANAR,
349     AV_CODEC_ID_PCM_DVD,
350     AV_CODEC_ID_PCM_F32BE,
351     AV_CODEC_ID_PCM_F32LE,
352     AV_CODEC_ID_PCM_F64BE,
353     AV_CODEC_ID_PCM_F64LE,
354     AV_CODEC_ID_PCM_BLURAY,
355     AV_CODEC_ID_PCM_LXF,
356     AV_CODEC_ID_S302M,
357     AV_CODEC_ID_PCM_S8_PLANAR,
358     AV_CODEC_ID_PCM_S24LE_PLANAR_DEPRECATED,
359     AV_CODEC_ID_PCM_S32LE_PLANAR_DEPRECATED,
360     AV_CODEC_ID_PCM_S24LE_PLANAR = MKBETAG(24,'P','S','P'),
361     AV_CODEC_ID_PCM_S32LE_PLANAR = MKBETAG(32,'P','S','P'),
362     AV_CODEC_ID_PCM_S16BE_PLANAR = MKBETAG('P','S','P',16),
363 
364     /* various ADPCM codecs */
365     AV_CODEC_ID_ADPCM_IMA_QT = 0x11000,
366     AV_CODEC_ID_ADPCM_IMA_WAV,
367     AV_CODEC_ID_ADPCM_IMA_DK3,
368     AV_CODEC_ID_ADPCM_IMA_DK4,
369     AV_CODEC_ID_ADPCM_IMA_WS,
370     AV_CODEC_ID_ADPCM_IMA_SMJPEG,
371     AV_CODEC_ID_ADPCM_MS,
372     AV_CODEC_ID_ADPCM_4XM,
373     AV_CODEC_ID_ADPCM_XA,
374     AV_CODEC_ID_ADPCM_ADX,
375     AV_CODEC_ID_ADPCM_EA,
376     AV_CODEC_ID_ADPCM_G726,
377     AV_CODEC_ID_ADPCM_CT,
378     AV_CODEC_ID_ADPCM_SWF,
379     AV_CODEC_ID_ADPCM_YAMAHA,
380     AV_CODEC_ID_ADPCM_SBPRO_4,
381     AV_CODEC_ID_ADPCM_SBPRO_3,
382     AV_CODEC_ID_ADPCM_SBPRO_2,
383     AV_CODEC_ID_ADPCM_THP,
384     AV_CODEC_ID_ADPCM_IMA_AMV,
385     AV_CODEC_ID_ADPCM_EA_R1,
386     AV_CODEC_ID_ADPCM_EA_R3,
387     AV_CODEC_ID_ADPCM_EA_R2,
388     AV_CODEC_ID_ADPCM_IMA_EA_SEAD,
389     AV_CODEC_ID_ADPCM_IMA_EA_EACS,
390     AV_CODEC_ID_ADPCM_EA_XAS,
391     AV_CODEC_ID_ADPCM_EA_MAXIS_XA,
392     AV_CODEC_ID_ADPCM_IMA_ISS,
393     AV_CODEC_ID_ADPCM_G722,
394     AV_CODEC_ID_ADPCM_IMA_APC,
395     AV_CODEC_ID_ADPCM_VIMA_DEPRECATED,
396     AV_CODEC_ID_ADPCM_VIMA = MKBETAG('V','I','M','A'),
397     AV_CODEC_ID_VIMA       = MKBETAG('V','I','M','A'),
398     AV_CODEC_ID_ADPCM_AFC  = MKBETAG('A','F','C',' '),
399     AV_CODEC_ID_ADPCM_IMA_OKI = MKBETAG('O','K','I',' '),
400     AV_CODEC_ID_ADPCM_DTK  = MKBETAG('D','T','K',' '),
401     AV_CODEC_ID_ADPCM_IMA_RAD = MKBETAG('R','A','D',' '),
402     AV_CODEC_ID_ADPCM_G726LE = MKBETAG('6','2','7','G'),
403 
404     /* AMR */
405     AV_CODEC_ID_AMR_NB = 0x12000,
406     AV_CODEC_ID_AMR_WB,
407 
408     /* RealAudio codecs*/
409     AV_CODEC_ID_RA_144 = 0x13000,
410     AV_CODEC_ID_RA_288,
411 
412     /* various DPCM codecs */
413     AV_CODEC_ID_ROQ_DPCM = 0x14000,
414     AV_CODEC_ID_INTERPLAY_DPCM,
415     AV_CODEC_ID_XAN_DPCM,
416     AV_CODEC_ID_SOL_DPCM,
417 
418     /* audio codecs */
419     AV_CODEC_ID_MP2 = 0x15000,
420     AV_CODEC_ID_MP3, ///< preferred ID for decoding MPEG audio layer 1, 2 or 3
421     AV_CODEC_ID_AAC,
422     AV_CODEC_ID_AC3,
423     AV_CODEC_ID_DTS,
424     AV_CODEC_ID_VORBIS,
425     AV_CODEC_ID_DVAUDIO,
426     AV_CODEC_ID_WMAV1,
427     AV_CODEC_ID_WMAV2,
428     AV_CODEC_ID_MACE3,
429     AV_CODEC_ID_MACE6,
430     AV_CODEC_ID_VMDAUDIO,
431     AV_CODEC_ID_FLAC,
432     AV_CODEC_ID_MP3ADU,
433     AV_CODEC_ID_MP3ON4,
434     AV_CODEC_ID_SHORTEN,
435     AV_CODEC_ID_ALAC,
436     AV_CODEC_ID_WESTWOOD_SND1,
437     AV_CODEC_ID_GSM, ///< as in Berlin toast format
438     AV_CODEC_ID_QDM2,
439     AV_CODEC_ID_COOK,
440     AV_CODEC_ID_TRUESPEECH,
441     AV_CODEC_ID_TTA,
442     AV_CODEC_ID_SMACKAUDIO,
443     AV_CODEC_ID_QCELP,
444     AV_CODEC_ID_WAVPACK,
445     AV_CODEC_ID_DSICINAUDIO,
446     AV_CODEC_ID_IMC,
447     AV_CODEC_ID_MUSEPACK7,
448     AV_CODEC_ID_MLP,
449     AV_CODEC_ID_GSM_MS, /* as found in WAV */
450     AV_CODEC_ID_ATRAC3,
451 #if FF_API_VOXWARE
452     AV_CODEC_ID_VOXWARE,
453 #endif
454     AV_CODEC_ID_APE,
455     AV_CODEC_ID_NELLYMOSER,
456     AV_CODEC_ID_MUSEPACK8,
457     AV_CODEC_ID_SPEEX,
458     AV_CODEC_ID_WMAVOICE,
459     AV_CODEC_ID_WMAPRO,
460     AV_CODEC_ID_WMALOSSLESS,
461     AV_CODEC_ID_ATRAC3P,
462     AV_CODEC_ID_EAC3,
463     AV_CODEC_ID_SIPR,
464     AV_CODEC_ID_MP1,
465     AV_CODEC_ID_TWINVQ,
466     AV_CODEC_ID_TRUEHD,
467     AV_CODEC_ID_MP4ALS,
468     AV_CODEC_ID_ATRAC1,
469     AV_CODEC_ID_BINKAUDIO_RDFT,
470     AV_CODEC_ID_BINKAUDIO_DCT,
471     AV_CODEC_ID_AAC_LATM,
472     AV_CODEC_ID_QDMC,
473     AV_CODEC_ID_CELT,
474     AV_CODEC_ID_G723_1,
475     AV_CODEC_ID_G729,
476     AV_CODEC_ID_8SVX_EXP,
477     AV_CODEC_ID_8SVX_FIB,
478     AV_CODEC_ID_BMV_AUDIO,
479     AV_CODEC_ID_RALF,
480     AV_CODEC_ID_IAC,
481     AV_CODEC_ID_ILBC,
482     AV_CODEC_ID_OPUS_DEPRECATED,
483     AV_CODEC_ID_COMFORT_NOISE,
484     AV_CODEC_ID_TAK_DEPRECATED,
485     AV_CODEC_ID_METASOUND,
486     AV_CODEC_ID_PAF_AUDIO_DEPRECATED,
487     AV_CODEC_ID_ON2AVC,
488     AV_CODEC_ID_FFWAVESYNTH = MKBETAG('F','F','W','S'),
489     AV_CODEC_ID_SONIC       = MKBETAG('S','O','N','C'),
490     AV_CODEC_ID_SONIC_LS    = MKBETAG('S','O','N','L'),
491     AV_CODEC_ID_PAF_AUDIO   = MKBETAG('P','A','F','A'),
492     AV_CODEC_ID_OPUS        = MKBETAG('O','P','U','S'),
493     AV_CODEC_ID_TAK         = MKBETAG('t','B','a','K'),
494     AV_CODEC_ID_EVRC        = MKBETAG('s','e','v','c'),
495     AV_CODEC_ID_SMV         = MKBETAG('s','s','m','v'),
496     AV_CODEC_ID_DSD_LSBF    = MKBETAG('D','S','D','L'),
497     AV_CODEC_ID_DSD_MSBF    = MKBETAG('D','S','D','M'),
498     AV_CODEC_ID_DSD_LSBF_PLANAR = MKBETAG('D','S','D','1'),
499     AV_CODEC_ID_DSD_MSBF_PLANAR = MKBETAG('D','S','D','8'),
500 
501     /* subtitle codecs */
502     AV_CODEC_ID_FIRST_SUBTITLE = 0x17000,          ///< A dummy ID pointing at the start of subtitle codecs.
503     AV_CODEC_ID_DVD_SUBTITLE = 0x17000,
504     AV_CODEC_ID_DVB_SUBTITLE,
505     AV_CODEC_ID_TEXT,  ///< raw UTF-8 text
506     AV_CODEC_ID_XSUB,
507     AV_CODEC_ID_SSA,
508     AV_CODEC_ID_MOV_TEXT,
509     AV_CODEC_ID_HDMV_PGS_SUBTITLE,
510     AV_CODEC_ID_DVB_TELETEXT,
511     AV_CODEC_ID_SRT,
512     AV_CODEC_ID_MICRODVD   = MKBETAG('m','D','V','D'),
513     AV_CODEC_ID_EIA_608    = MKBETAG('c','6','0','8'),
514     AV_CODEC_ID_JACOSUB    = MKBETAG('J','S','U','B'),
515     AV_CODEC_ID_SAMI       = MKBETAG('S','A','M','I'),
516     AV_CODEC_ID_REALTEXT   = MKBETAG('R','T','X','T'),
517     AV_CODEC_ID_SUBVIEWER1 = MKBETAG('S','b','V','1'),
518     AV_CODEC_ID_SUBVIEWER  = MKBETAG('S','u','b','V'),
519     AV_CODEC_ID_SUBRIP     = MKBETAG('S','R','i','p'),
520     AV_CODEC_ID_WEBVTT     = MKBETAG('W','V','T','T'),
521     AV_CODEC_ID_MPL2       = MKBETAG('M','P','L','2'),
522     AV_CODEC_ID_VPLAYER    = MKBETAG('V','P','l','r'),
523     AV_CODEC_ID_PJS        = MKBETAG('P','h','J','S'),
524     AV_CODEC_ID_ASS        = MKBETAG('A','S','S',' '),  ///< ASS as defined in Matroska
525 
526     /* other specific kind of codecs (generally used for attachments) */
527     AV_CODEC_ID_FIRST_UNKNOWN = 0x18000,           ///< A dummy ID pointing at the start of various fake codecs.
528     AV_CODEC_ID_TTF = 0x18000,
529     AV_CODEC_ID_BINTEXT    = MKBETAG('B','T','X','T'),
530     AV_CODEC_ID_XBIN       = MKBETAG('X','B','I','N'),
531     AV_CODEC_ID_IDF        = MKBETAG( 0 ,'I','D','F'),
532     AV_CODEC_ID_OTF        = MKBETAG( 0 ,'O','T','F'),
533     AV_CODEC_ID_SMPTE_KLV  = MKBETAG('K','L','V','A'),
534     AV_CODEC_ID_DVD_NAV    = MKBETAG('D','N','A','V'),
535     AV_CODEC_ID_TIMED_ID3  = MKBETAG('T','I','D','3'),
536     AV_CODEC_ID_BIN_DATA   = MKBETAG('D','A','T','A'),
537 
538 
539     AV_CODEC_ID_PROBE = 0x19000, ///< codec_id is not known (like AV_CODEC_ID_NONE) but lavf should attempt to identify it
540 
541     AV_CODEC_ID_MPEG2TS = 0x20000, /**< _FAKE_ codec to indicate a raw MPEG-2 TS
542                                 * stream (only used by libavformat) */
543     AV_CODEC_ID_MPEG4SYSTEMS = 0x20001, /**< _FAKE_ codec to indicate a MPEG-4 Systems
544                                 * stream (only used by libavformat) */
545     AV_CODEC_ID_FFMETADATA = 0x21000,   ///< Dummy codec for streams containing only metadata information.
546 
547 #if FF_API_CODEC_ID
548 #include "old_codec_ids.h"
549 #endif
550 };
551 
552 /**
553  * This struct describes the properties of a single codec described by an
554  * AVCodecID.
555  * @see avcodec_get_descriptor()
556  */
557 typedef struct AVCodecDescriptor {
558     enum AVCodecID     id;
559     enum AVMediaType type;
560     /**
561      * Name of the codec described by this descriptor. It is non-empty and
562      * unique for each codec descriptor. It should contain alphanumeric
563      * characters and '_' only.
564      */
565     const char      *name;
566     /**
567      * A more descriptive name for this codec. May be NULL.
568      */
569     const char *long_name;
570     /**
571      * Codec properties, a combination of AV_CODEC_PROP_* flags.
572      */
573     int             props;
574 
575     /**
576      * MIME type(s) associated with the codec.
577      * May be NULL; if not, a NULL-terminated array of MIME types.
578      * The first item is always non-NULL and is the preferred MIME type.
579      */
580     const char *const *mime_types;
581 } AVCodecDescriptor;
582 
583 /**
584  * Codec uses only intra compression.
585  * Video codecs only.
586  */
587 #define AV_CODEC_PROP_INTRA_ONLY    (1 << 0)
588 /**
589  * Codec supports lossy compression. Audio and video codecs only.
590  * @note a codec may support both lossy and lossless
591  * compression modes
592  */
593 #define AV_CODEC_PROP_LOSSY         (1 << 1)
594 /**
595  * Codec supports lossless compression. Audio and video codecs only.
596  */
597 #define AV_CODEC_PROP_LOSSLESS      (1 << 2)
598 /**
599  * Codec supports frame reordering. That is, the coded order (the order in which
600  * the encoded packets are output by the encoders / stored / input to the
601  * decoders) may be different from the presentation order of the corresponding
602  * frames.
603  *
604  * For codecs that do not have this property set, PTS and DTS should always be
605  * equal.
606  */
607 #define AV_CODEC_PROP_REORDER       (1 << 3)
608 /**
609  * Subtitle codec is bitmap based
610  * Decoded AVSubtitle data can be read from the AVSubtitleRect->pict field.
611  */
612 #define AV_CODEC_PROP_BITMAP_SUB    (1 << 16)
613 /**
614  * Subtitle codec is text based.
615  * Decoded AVSubtitle data can be read from the AVSubtitleRect->ass field.
616  */
617 #define AV_CODEC_PROP_TEXT_SUB      (1 << 17)
618 
619 /**
620  * @ingroup lavc_decoding
621  * Required number of additionally allocated bytes at the end of the input bitstream for decoding.
622  * This is mainly needed because some optimized bitstream readers read
623  * 32 or 64 bit at once and could read over the end.<br>
624  * Note: If the first 23 bits of the additional bytes are not 0, then damaged
625  * MPEG bitstreams could cause overread and segfault.
626  */
627 #define FF_INPUT_BUFFER_PADDING_SIZE 32
628 
629 /**
630  * @ingroup lavc_encoding
631  * minimum encoding buffer size
632  * Used to avoid some checks during header writing.
633  */
634 #define FF_MIN_BUFFER_SIZE 16384
635 
636 
637 /**
638  * @ingroup lavc_encoding
639  * motion estimation type.
640  */
641 enum Motion_Est_ID {
642     ME_ZERO = 1,    ///< no search, that is use 0,0 vector whenever one is needed
643     ME_FULL,
644     ME_LOG,
645     ME_PHODS,
646     ME_EPZS,        ///< enhanced predictive zonal search
647     ME_X1,          ///< reserved for experiments
648     ME_HEX,         ///< hexagon based search
649     ME_UMH,         ///< uneven multi-hexagon search
650     ME_TESA,        ///< transformed exhaustive search algorithm
651     ME_ITER=50,     ///< iterative search
652 };
653 
654 /**
655  * @ingroup lavc_decoding
656  */
657 enum AVDiscard{
658     /* We leave some space between them for extensions (drop some
659      * keyframes for intra-only or drop just some bidir frames). */
660     AVDISCARD_NONE    =-16, ///< discard nothing
661     AVDISCARD_DEFAULT =  0, ///< discard useless packets like 0 size packets in avi
662     AVDISCARD_NONREF  =  8, ///< discard all non reference
663     AVDISCARD_BIDIR   = 16, ///< discard all bidirectional frames
664     AVDISCARD_NONINTRA= 24, ///< discard all non intra frames
665     AVDISCARD_NONKEY  = 32, ///< discard all frames except keyframes
666     AVDISCARD_ALL     = 48, ///< discard all
667 };
668 
669 enum AVAudioServiceType {
670     AV_AUDIO_SERVICE_TYPE_MAIN              = 0,
671     AV_AUDIO_SERVICE_TYPE_EFFECTS           = 1,
672     AV_AUDIO_SERVICE_TYPE_VISUALLY_IMPAIRED = 2,
673     AV_AUDIO_SERVICE_TYPE_HEARING_IMPAIRED  = 3,
674     AV_AUDIO_SERVICE_TYPE_DIALOGUE          = 4,
675     AV_AUDIO_SERVICE_TYPE_COMMENTARY        = 5,
676     AV_AUDIO_SERVICE_TYPE_EMERGENCY         = 6,
677     AV_AUDIO_SERVICE_TYPE_VOICE_OVER        = 7,
678     AV_AUDIO_SERVICE_TYPE_KARAOKE           = 8,
679     AV_AUDIO_SERVICE_TYPE_NB                   , ///< Not part of ABI
680 };
681 
682 /**
683  * @ingroup lavc_encoding
684  */
685 typedef struct RcOverride{
686     int start_frame;
687     int end_frame;
688     int qscale; // If this is 0 then quality_factor will be used instead.
689     float quality_factor;
690 } RcOverride;
691 
692 #if FF_API_MAX_BFRAMES
693 /**
694  * @deprecated there is no libavcodec-wide limit on the number of B-frames
695  */
696 #define FF_MAX_B_FRAMES 16
697 #endif
698 
699 /* encoding support
700    These flags can be passed in AVCodecContext.flags before initialization.
701    Note: Not everything is supported yet.
702 */
703 
704 /**
705  * Allow decoders to produce frames with data planes that are not aligned
706  * to CPU requirements (e.g. due to cropping).
707  */
708 #define CODEC_FLAG_UNALIGNED 0x0001
709 #define CODEC_FLAG_QSCALE 0x0002  ///< Use fixed qscale.
710 #define CODEC_FLAG_4MV    0x0004  ///< 4 MV per MB allowed / advanced prediction for H.263.
711 #define CODEC_FLAG_OUTPUT_CORRUPT 0x0008 ///< Output even those frames that might be corrupted
712 #define CODEC_FLAG_QPEL   0x0010  ///< Use qpel MC.
713 #if FF_API_GMC
714 /**
715  * @deprecated use the "gmc" private option of the libxvid encoder
716  */
717 #define CODEC_FLAG_GMC    0x0020  ///< Use GMC.
718 #endif
719 #if FF_API_MV0
720 /**
721  * @deprecated use the flag "mv0" in the "mpv_flags" private option of the
722  * mpegvideo encoders
723  */
724 #define CODEC_FLAG_MV0    0x0040
725 #endif
726 #if FF_API_INPUT_PRESERVED
727 /**
728  * @deprecated passing reference-counted frames to the encoders replaces this
729  * flag
730  */
731 #define CODEC_FLAG_INPUT_PRESERVED 0x0100
732 #endif
733 #define CODEC_FLAG_PASS1           0x0200   ///< Use internal 2pass ratecontrol in first pass mode.
734 #define CODEC_FLAG_PASS2           0x0400   ///< Use internal 2pass ratecontrol in second pass mode.
735 #define CODEC_FLAG_GRAY            0x2000   ///< Only decode/encode grayscale.
736 #if FF_API_EMU_EDGE
737 /**
738  * @deprecated edges are not used/required anymore. I.e. this flag is now always
739  * set.
740  */
741 #define CODEC_FLAG_EMU_EDGE        0x4000
742 #endif
743 #define CODEC_FLAG_PSNR            0x8000   ///< error[?] variables will be set during encoding.
744 #define CODEC_FLAG_TRUNCATED       0x00010000 /** Input bitstream might be truncated at a random
745                                                   location instead of only at frame boundaries. */
746 #if FF_API_NORMALIZE_AQP
747 /**
748  * @deprecated use the flag "naq" in the "mpv_flags" private option of the
749  * mpegvideo encoders
750  */
751 #define CODEC_FLAG_NORMALIZE_AQP  0x00020000
752 #endif
753 #define CODEC_FLAG_INTERLACED_DCT 0x00040000 ///< Use interlaced DCT.
754 #define CODEC_FLAG_LOW_DELAY      0x00080000 ///< Force low delay.
755 #define CODEC_FLAG_GLOBAL_HEADER  0x00400000 ///< Place global headers in extradata instead of every keyframe.
756 #define CODEC_FLAG_BITEXACT       0x00800000 ///< Use only bitexact stuff (except (I)DCT).
757 /* Fx : Flag for h263+ extra options */
758 #define CODEC_FLAG_AC_PRED        0x01000000 ///< H.263 advanced intra coding / MPEG-4 AC prediction
759 #define CODEC_FLAG_LOOP_FILTER    0x00000800 ///< loop filter
760 #define CODEC_FLAG_INTERLACED_ME  0x20000000 ///< interlaced motion estimation
761 #define CODEC_FLAG_CLOSED_GOP     0x80000000
762 #define CODEC_FLAG2_FAST          0x00000001 ///< Allow non spec compliant speedup tricks.
763 #define CODEC_FLAG2_NO_OUTPUT     0x00000004 ///< Skip bitstream encoding.
764 #define CODEC_FLAG2_LOCAL_HEADER  0x00000008 ///< Place global headers at every keyframe instead of in extradata.
765 #define CODEC_FLAG2_DROP_FRAME_TIMECODE 0x00002000 ///< timecode is in drop frame format. DEPRECATED!!!!
766 #define CODEC_FLAG2_IGNORE_CROP   0x00010000 ///< Discard cropping information from SPS.
767 
768 #define CODEC_FLAG2_CHUNKS        0x00008000 ///< Input bitstream might be truncated at a packet boundaries instead of only at frame boundaries.
769 #define CODEC_FLAG2_SHOW_ALL      0x00400000 ///< Show all frames before the first keyframe
770 #define CODEC_FLAG2_EXPORT_MVS    0x10000000 ///< Export motion vectors through frame side data
771 
772 /* Unsupported options :
773  *              Syntax Arithmetic coding (SAC)
774  *              Reference Picture Selection
775  *              Independent Segment Decoding */
776 /* /Fx */
777 /* codec capabilities */
778 
779 #define CODEC_CAP_DRAW_HORIZ_BAND 0x0001 ///< Decoder can use draw_horiz_band callback.
780 /**
781  * Codec uses get_buffer() for allocating buffers and supports custom allocators.
782  * If not set, it might not use get_buffer() at all or use operations that
783  * assume the buffer was allocated by avcodec_default_get_buffer.
784  */
785 #define CODEC_CAP_DR1             0x0002
786 #define CODEC_CAP_TRUNCATED       0x0008
787 #if FF_API_XVMC
788 /* Codec can export data for HW decoding. This flag indicates that
789  * the codec would call get_format() with list that might contain HW accelerated
790  * pixel formats (XvMC, VDPAU, VAAPI, etc). The application can pick any of them
791  * including raw image format.
792  * The application can use the passed context to determine bitstream version,
793  * chroma format, resolution etc.
794  */
795 #define CODEC_CAP_HWACCEL         0x0010
796 #endif /* FF_API_XVMC */
797 /**
798  * Encoder or decoder requires flushing with NULL input at the end in order to
799  * give the complete and correct output.
800  *
801  * NOTE: If this flag is not set, the codec is guaranteed to never be fed with
802  *       with NULL data. The user can still send NULL data to the public encode
803  *       or decode function, but libavcodec will not pass it along to the codec
804  *       unless this flag is set.
805  *
806  * Decoders:
807  * The decoder has a non-zero delay and needs to be fed with avpkt->data=NULL,
808  * avpkt->size=0 at the end to get the delayed data until the decoder no longer
809  * returns frames.
810  *
811  * Encoders:
812  * The encoder needs to be fed with NULL data at the end of encoding until the
813  * encoder no longer returns data.
814  *
815  * NOTE: For encoders implementing the AVCodec.encode2() function, setting this
816  *       flag also means that the encoder must set the pts and duration for
817  *       each output packet. If this flag is not set, the pts and duration will
818  *       be determined by libavcodec from the input frame.
819  */
820 #define CODEC_CAP_DELAY           0x0020
821 /**
822  * Codec can be fed a final frame with a smaller size.
823  * This can be used to prevent truncation of the last audio samples.
824  */
825 #define CODEC_CAP_SMALL_LAST_FRAME 0x0040
826 #if FF_API_CAP_VDPAU
827 /**
828  * Codec can export data for HW decoding (VDPAU).
829  */
830 #define CODEC_CAP_HWACCEL_VDPAU    0x0080
831 #endif
832 /**
833  * Codec can output multiple frames per AVPacket
834  * Normally demuxers return one frame at a time, demuxers which do not do
835  * are connected to a parser to split what they return into proper frames.
836  * This flag is reserved to the very rare category of codecs which have a
837  * bitstream that cannot be split into frames without timeconsuming
838  * operations like full decoding. Demuxers carring such bitstreams thus
839  * may return multiple frames in a packet. This has many disadvantages like
840  * prohibiting stream copy in many cases thus it should only be considered
841  * as a last resort.
842  */
843 #define CODEC_CAP_SUBFRAMES        0x0100
844 /**
845  * Codec is experimental and is thus avoided in favor of non experimental
846  * encoders
847  */
848 #define CODEC_CAP_EXPERIMENTAL     0x0200
849 /**
850  * Codec should fill in channel configuration and samplerate instead of container
851  */
852 #define CODEC_CAP_CHANNEL_CONF     0x0400
853 #if FF_API_NEG_LINESIZES
854 /**
855  * @deprecated no codecs use this capability
856  */
857 #define CODEC_CAP_NEG_LINESIZES    0x0800
858 #endif
859 /**
860  * Codec supports frame-level multithreading.
861  */
862 #define CODEC_CAP_FRAME_THREADS    0x1000
863 /**
864  * Codec supports slice-based (or partition-based) multithreading.
865  */
866 #define CODEC_CAP_SLICE_THREADS    0x2000
867 /**
868  * Codec supports changed parameters at any point.
869  */
870 #define CODEC_CAP_PARAM_CHANGE     0x4000
871 /**
872  * Codec supports avctx->thread_count == 0 (auto).
873  */
874 #define CODEC_CAP_AUTO_THREADS     0x8000
875 /**
876  * Audio encoder supports receiving a different number of samples in each call.
877  */
878 #define CODEC_CAP_VARIABLE_FRAME_SIZE 0x10000
879 /**
880  * Codec is intra only.
881  */
882 #define CODEC_CAP_INTRA_ONLY       0x40000000
883 /**
884  * Codec is lossless.
885  */
886 #define CODEC_CAP_LOSSLESS         0x80000000
887 
888 #if FF_API_MB_TYPE
889 //The following defines may change, don't expect compatibility if you use them.
890 #define MB_TYPE_INTRA4x4   0x0001
891 #define MB_TYPE_INTRA16x16 0x0002 //FIXME H.264-specific
892 #define MB_TYPE_INTRA_PCM  0x0004 //FIXME H.264-specific
893 #define MB_TYPE_16x16      0x0008
894 #define MB_TYPE_16x8       0x0010
895 #define MB_TYPE_8x16       0x0020
896 #define MB_TYPE_8x8        0x0040
897 #define MB_TYPE_INTERLACED 0x0080
898 #define MB_TYPE_DIRECT2    0x0100 //FIXME
899 #define MB_TYPE_ACPRED     0x0200
900 #define MB_TYPE_GMC        0x0400
901 #define MB_TYPE_SKIP       0x0800
902 #define MB_TYPE_P0L0       0x1000
903 #define MB_TYPE_P1L0       0x2000
904 #define MB_TYPE_P0L1       0x4000
905 #define MB_TYPE_P1L1       0x8000
906 #define MB_TYPE_L0         (MB_TYPE_P0L0 | MB_TYPE_P1L0)
907 #define MB_TYPE_L1         (MB_TYPE_P0L1 | MB_TYPE_P1L1)
908 #define MB_TYPE_L0L1       (MB_TYPE_L0   | MB_TYPE_L1)
909 #define MB_TYPE_QUANT      0x00010000
910 #define MB_TYPE_CBP        0x00020000
911 //Note bits 24-31 are reserved for codec specific use (h264 ref0, mpeg1 0mv, ...)
912 #endif
913 
914 /**
915  * Pan Scan area.
916  * This specifies the area which should be displayed.
917  * Note there may be multiple such areas for one frame.
918  */
919 typedef struct AVPanScan{
920     /**
921      * id
922      * - encoding: Set by user.
923      * - decoding: Set by libavcodec.
924      */
925     int id;
926 
927     /**
928      * width and height in 1/16 pel
929      * - encoding: Set by user.
930      * - decoding: Set by libavcodec.
931      */
932     int width;
933     int height;
934 
935     /**
936      * position of the top left corner in 1/16 pel for up to 3 fields/frames
937      * - encoding: Set by user.
938      * - decoding: Set by libavcodec.
939      */
940     int16_t position[3][2];
941 }AVPanScan;
942 
943 #if FF_API_QSCALE_TYPE
944 #define FF_QSCALE_TYPE_MPEG1 0
945 #define FF_QSCALE_TYPE_MPEG2 1
946 #define FF_QSCALE_TYPE_H264  2
947 #define FF_QSCALE_TYPE_VP56  3
948 #endif
949 
950 #if FF_API_GET_BUFFER
951 #define FF_BUFFER_TYPE_INTERNAL 1
952 #define FF_BUFFER_TYPE_USER     2 ///< direct rendering buffers (image is (de)allocated by user)
953 #define FF_BUFFER_TYPE_SHARED   4 ///< Buffer from somewhere else; don't deallocate image (data/base), all other tables are not shared.
954 #define FF_BUFFER_TYPE_COPY     8 ///< Just a (modified) copy of some other buffer, don't deallocate anything.
955 
956 #define FF_BUFFER_HINTS_VALID    0x01 // Buffer hints value is meaningful (if 0 ignore).
957 #define FF_BUFFER_HINTS_READABLE 0x02 // Codec will read from buffer.
958 #define FF_BUFFER_HINTS_PRESERVE 0x04 // User must not alter buffer content.
959 #define FF_BUFFER_HINTS_REUSABLE 0x08 // Codec will reuse the buffer (update).
960 #endif
961 
962 /**
963  * The decoder will keep a reference to the frame and may reuse it later.
964  */
965 #define AV_GET_BUFFER_FLAG_REF (1 << 0)
966 
967 /**
968  * @defgroup lavc_packet AVPacket
969  *
970  * Types and functions for working with AVPacket.
971  * @{
972  */
973 enum AVPacketSideDataType {
974     AV_PKT_DATA_PALETTE,
975     AV_PKT_DATA_NEW_EXTRADATA,
976 
977     /**
978      * An AV_PKT_DATA_PARAM_CHANGE side data packet is laid out as follows:
979      * @code
980      * u32le param_flags
981      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT)
982      *     s32le channel_count
983      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT)
984      *     u64le channel_layout
985      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE)
986      *     s32le sample_rate
987      * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS)
988      *     s32le width
989      *     s32le height
990      * @endcode
991      */
992     AV_PKT_DATA_PARAM_CHANGE,
993 
994     /**
995      * An AV_PKT_DATA_H263_MB_INFO side data packet contains a number of
996      * structures with info about macroblocks relevant to splitting the
997      * packet into smaller packets on macroblock edges (e.g. as for RFC 2190).
998      * That is, it does not necessarily contain info about all macroblocks,
999      * as long as the distance between macroblocks in the info is smaller
1000      * than the target payload size.
1001      * Each MB info structure is 12 bytes, and is laid out as follows:
1002      * @code
1003      * u32le bit offset from the start of the packet
1004      * u8    current quantizer at the start of the macroblock
1005      * u8    GOB number
1006      * u16le macroblock address within the GOB
1007      * u8    horizontal MV predictor
1008      * u8    vertical MV predictor
1009      * u8    horizontal MV predictor for block number 3
1010      * u8    vertical MV predictor for block number 3
1011      * @endcode
1012      */
1013     AV_PKT_DATA_H263_MB_INFO,
1014 
1015     /**
1016      * This side data should be associated with an audio stream and contains
1017      * ReplayGain information in form of the AVReplayGain struct.
1018      */
1019     AV_PKT_DATA_REPLAYGAIN,
1020 
1021     /**
1022      * This side data contains a 3x3 transformation matrix describing an affine
1023      * transformation that needs to be applied to the decoded video frames for
1024      * correct presentation.
1025      *
1026      * See libavutil/display.h for a detailed description of the data.
1027      */
1028     AV_PKT_DATA_DISPLAYMATRIX,
1029 
1030     /**
1031      * This side data should be associated with a video stream and contains
1032      * Stereoscopic 3D information in form of the AVStereo3D struct.
1033      */
1034     AV_PKT_DATA_STEREO3D,
1035 
1036     /**
1037      * Recommmends skipping the specified number of samples
1038      * @code
1039      * u32le number of samples to skip from start of this packet
1040      * u32le number of samples to skip from end of this packet
1041      * u8    reason for start skip
1042      * u8    reason for end   skip (0=padding silence, 1=convergence)
1043      * @endcode
1044      */
1045     AV_PKT_DATA_SKIP_SAMPLES=70,
1046 
1047     /**
1048      * An AV_PKT_DATA_JP_DUALMONO side data packet indicates that
1049      * the packet may contain "dual mono" audio specific to Japanese DTV
1050      * and if it is true, recommends only the selected channel to be used.
1051      * @code
1052      * u8    selected channels (0=mail/left, 1=sub/right, 2=both)
1053      * @endcode
1054      */
1055     AV_PKT_DATA_JP_DUALMONO,
1056 
1057     /**
1058      * A list of zero terminated key/value strings. There is no end marker for
1059      * the list, so it is required to rely on the side data size to stop.
1060      */
1061     AV_PKT_DATA_STRINGS_METADATA,
1062 
1063     /**
1064      * Subtitle event position
1065      * @code
1066      * u32le x1
1067      * u32le y1
1068      * u32le x2
1069      * u32le y2
1070      * @endcode
1071      */
1072     AV_PKT_DATA_SUBTITLE_POSITION,
1073 
1074     /**
1075      * Data found in BlockAdditional element of matroska container. There is
1076      * no end marker for the data, so it is required to rely on the side data
1077      * size to recognize the end. 8 byte id (as found in BlockAddId) followed
1078      * by data.
1079      */
1080     AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
1081 
1082     /**
1083      * The optional first identifier line of a WebVTT cue.
1084      */
1085     AV_PKT_DATA_WEBVTT_IDENTIFIER,
1086 
1087     /**
1088      * The optional settings (rendering instructions) that immediately
1089      * follow the timestamp specifier of a WebVTT cue.
1090      */
1091     AV_PKT_DATA_WEBVTT_SETTINGS,
1092 
1093     /**
1094      * A list of zero terminated key/value strings. There is no end marker for
1095      * the list, so it is required to rely on the side data size to stop. This
1096      * side data includes updated metadata which appeared in the stream.
1097      */
1098     AV_PKT_DATA_METADATA_UPDATE,
1099 };
1100 
1101 typedef struct AVPacketSideData {
1102     uint8_t *data;
1103     int      size;
1104     enum AVPacketSideDataType type;
1105 } AVPacketSideData;
1106 
1107 /**
1108  * This structure stores compressed data. It is typically exported by demuxers
1109  * and then passed as input to decoders, or received as output from encoders and
1110  * then passed to muxers.
1111  *
1112  * For video, it should typically contain one compressed frame. For audio it may
1113  * contain several compressed frames.
1114  *
1115  * AVPacket is one of the few structs in FFmpeg, whose size is a part of public
1116  * ABI. Thus it may be allocated on stack and no new fields can be added to it
1117  * without libavcodec and libavformat major bump.
1118  *
1119  * The semantics of data ownership depends on the buf or destruct (deprecated)
1120  * fields. If either is set, the packet data is dynamically allocated and is
1121  * valid indefinitely until av_free_packet() is called (which in turn calls
1122  * av_buffer_unref()/the destruct callback to free the data). If neither is set,
1123  * the packet data is typically backed by some static buffer somewhere and is
1124  * only valid for a limited time (e.g. until the next read call when demuxing).
1125  *
1126  * The side data is always allocated with av_malloc() and is freed in
1127  * av_free_packet().
1128  */
1129 typedef struct AVPacket {
1130     /**
1131      * A reference to the reference-counted buffer where the packet data is
1132      * stored.
1133      * May be NULL, then the packet data is not reference-counted.
1134      */
1135     AVBufferRef *buf;
1136     /**
1137      * Presentation timestamp in AVStream->time_base units; the time at which
1138      * the decompressed packet will be presented to the user.
1139      * Can be AV_NOPTS_VALUE if it is not stored in the file.
1140      * pts MUST be larger or equal to dts as presentation cannot happen before
1141      * decompression, unless one wants to view hex dumps. Some formats misuse
1142      * the terms dts and pts/cts to mean something different. Such timestamps
1143      * must be converted to true pts/dts before they are stored in AVPacket.
1144      */
1145     int64_t pts;
1146     /**
1147      * Decompression timestamp in AVStream->time_base units; the time at which
1148      * the packet is decompressed.
1149      * Can be AV_NOPTS_VALUE if it is not stored in the file.
1150      */
1151     int64_t dts;
1152     uint8_t *data;
1153     int   size;
1154     int   stream_index;
1155     /**
1156      * A combination of AV_PKT_FLAG values
1157      */
1158     int   flags;
1159     /**
1160      * Additional packet data that can be provided by the container.
1161      * Packet can contain several types of side information.
1162      */
1163     AVPacketSideData *side_data;
1164     int side_data_elems;
1165 
1166     /**
1167      * Duration of this packet in AVStream->time_base units, 0 if unknown.
1168      * Equals next_pts - this_pts in presentation order.
1169      */
1170     int   duration;
1171 #if FF_API_DESTRUCT_PACKET
1172     attribute_deprecated
1173     void  (*destruct)(struct AVPacket *);
1174     attribute_deprecated
1175     void  *priv;
1176 #endif
1177     int64_t pos;                            ///< byte position in stream, -1 if unknown
1178 
1179     /**
1180      * Time difference in AVStream->time_base units from the pts of this
1181      * packet to the point at which the output from the decoder has converged
1182      * independent from the availability of previous frames. That is, the
1183      * frames are virtually identical no matter if decoding started from
1184      * the very first frame or from this keyframe.
1185      * Is AV_NOPTS_VALUE if unknown.
1186      * This field is not the display duration of the current packet.
1187      * This field has no meaning if the packet does not have AV_PKT_FLAG_KEY
1188      * set.
1189      *
1190      * The purpose of this field is to allow seeking in streams that have no
1191      * keyframes in the conventional sense. It corresponds to the
1192      * recovery point SEI in H.264 and match_time_delta in NUT. It is also
1193      * essential for some types of subtitle streams to ensure that all
1194      * subtitles are correctly displayed after seeking.
1195      */
1196     int64_t convergence_duration;
1197 } AVPacket;
1198 #define AV_PKT_FLAG_KEY     0x0001 ///< The packet contains a keyframe
1199 #define AV_PKT_FLAG_CORRUPT 0x0002 ///< The packet content is corrupted
1200 
1201 enum AVSideDataParamChangeFlags {
1202     AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT  = 0x0001,
1203     AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT = 0x0002,
1204     AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE    = 0x0004,
1205     AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS     = 0x0008,
1206 };
1207 /**
1208  * @}
1209  */
1210 
1211 struct AVCodecInternal;
1212 
1213 enum AVFieldOrder {
1214     AV_FIELD_UNKNOWN,
1215     AV_FIELD_PROGRESSIVE,
1216     AV_FIELD_TT,          //< Top coded_first, top displayed first
1217     AV_FIELD_BB,          //< Bottom coded first, bottom displayed first
1218     AV_FIELD_TB,          //< Top coded first, bottom displayed first
1219     AV_FIELD_BT,          //< Bottom coded first, top displayed first
1220 };
1221 
1222 /**
1223  * main external API structure.
1224  * New fields can be added to the end with minor version bumps.
1225  * Removal, reordering and changes to existing fields require a major
1226  * version bump.
1227  * Please use AVOptions (av_opt* / av_set/get*()) to access these fields from user
1228  * applications.
1229  * sizeof(AVCodecContext) must not be used outside libav*.
1230  */
1231 typedef struct AVCodecContext {
1232     /**
1233      * information on struct for av_log
1234      * - set by avcodec_alloc_context3
1235      */
1236     const AVClass *av_class;
1237     int log_level_offset;
1238 
1239     enum AVMediaType codec_type; /* see AVMEDIA_TYPE_xxx */
1240     const struct AVCodec  *codec;
1241 #if FF_API_CODEC_NAME
1242     /**
1243      * @deprecated this field is not used for anything in libavcodec
1244      */
1245     attribute_deprecated
1246     char             codec_name[32];
1247 #endif
1248     enum AVCodecID     codec_id; /* see AV_CODEC_ID_xxx */
1249 
1250     /**
1251      * fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
1252      * This is used to work around some encoder bugs.
1253      * A demuxer should set this to what is stored in the field used to identify the codec.
1254      * If there are multiple such fields in a container then the demuxer should choose the one
1255      * which maximizes the information about the used codec.
1256      * If the codec tag field in a container is larger than 32 bits then the demuxer should
1257      * remap the longer ID to 32 bits with a table or other structure. Alternatively a new
1258      * extra_codec_tag + size could be added but for this a clear advantage must be demonstrated
1259      * first.
1260      * - encoding: Set by user, if not then the default based on codec_id will be used.
1261      * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
1262      */
1263     unsigned int codec_tag;
1264 
1265     /**
1266      * fourcc from the AVI stream header (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
1267      * This is used to work around some encoder bugs.
1268      * - encoding: unused
1269      * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
1270      */
1271     unsigned int stream_codec_tag;
1272 
1273     void *priv_data;
1274 
1275     /**
1276      * Private context used for internal data.
1277      *
1278      * Unlike priv_data, this is not codec-specific. It is used in general
1279      * libavcodec functions.
1280      */
1281     struct AVCodecInternal *internal;
1282 
1283     /**
1284      * Private data of the user, can be used to carry app specific stuff.
1285      * - encoding: Set by user.
1286      * - decoding: Set by user.
1287      */
1288     void *opaque;
1289 
1290     /**
1291      * the average bitrate
1292      * - encoding: Set by user; unused for constant quantizer encoding.
1293      * - decoding: Set by libavcodec. 0 or some bitrate if this info is available in the stream.
1294      */
1295     int bit_rate;
1296 
1297     /**
1298      * number of bits the bitstream is allowed to diverge from the reference.
1299      *           the reference can be CBR (for CBR pass1) or VBR (for pass2)
1300      * - encoding: Set by user; unused for constant quantizer encoding.
1301      * - decoding: unused
1302      */
1303     int bit_rate_tolerance;
1304 
1305     /**
1306      * Global quality for codecs which cannot change it per frame.
1307      * This should be proportional to MPEG-1/2/4 qscale.
1308      * - encoding: Set by user.
1309      * - decoding: unused
1310      */
1311     int global_quality;
1312 
1313     /**
1314      * - encoding: Set by user.
1315      * - decoding: unused
1316      */
1317     int compression_level;
1318 #define FF_COMPRESSION_DEFAULT -1
1319 
1320     /**
1321      * CODEC_FLAG_*.
1322      * - encoding: Set by user.
1323      * - decoding: Set by user.
1324      */
1325     int flags;
1326 
1327     /**
1328      * CODEC_FLAG2_*
1329      * - encoding: Set by user.
1330      * - decoding: Set by user.
1331      */
1332     int flags2;
1333 
1334     /**
1335      * some codecs need / can use extradata like Huffman tables.
1336      * mjpeg: Huffman tables
1337      * rv10: additional flags
1338      * mpeg4: global headers (they can be in the bitstream or here)
1339      * The allocated memory should be FF_INPUT_BUFFER_PADDING_SIZE bytes larger
1340      * than extradata_size to avoid problems if it is read with the bitstream reader.
1341      * The bytewise contents of extradata must not depend on the architecture or CPU endianness.
1342      * - encoding: Set/allocated/freed by libavcodec.
1343      * - decoding: Set/allocated/freed by user.
1344      */
1345     uint8_t *extradata;
1346     int extradata_size;
1347 
1348     /**
1349      * This is the fundamental unit of time (in seconds) in terms
1350      * of which frame timestamps are represented. For fixed-fps content,
1351      * timebase should be 1/framerate and timestamp increments should be
1352      * identically 1.
1353      * - encoding: MUST be set by user.
1354      * - decoding: Set by libavcodec.
1355      */
1356     AVRational time_base;
1357 
1358     /**
1359      * For some codecs, the time base is closer to the field rate than the frame rate.
1360      * Most notably, H.264 and MPEG-2 specify time_base as half of frame duration
1361      * if no telecine is used ...
1362      *
1363      * Set to time_base ticks per frame. Default 1, e.g., H.264/MPEG-2 set it to 2.
1364      */
1365     int ticks_per_frame;
1366 
1367     /**
1368      * Codec delay.
1369      *
1370      * Encoding: Number of frames delay there will be from the encoder input to
1371      *           the decoder output. (we assume the decoder matches the spec)
1372      * Decoding: Number of frames delay in addition to what a standard decoder
1373      *           as specified in the spec would produce.
1374      *
1375      * Video:
1376      *   Number of frames the decoded output will be delayed relative to the
1377      *   encoded input.
1378      *
1379      * Audio:
1380      *   For encoding, this is the number of "priming" samples added by the
1381      *   encoder to the beginning of the stream. The decoded output will be
1382      *   delayed by this many samples relative to the input to the encoder (or
1383      *   more, if the decoder adds its own padding).
1384      *   The timestamps on the output packets are adjusted by the encoder so
1385      *   that they always refer to the first sample of the data actually
1386      *   contained in the packet, including any added padding.
1387      *   E.g. if the timebase is 1/samplerate and the timestamp of the first
1388      *   input sample is 0, the timestamp of the first output packet will be
1389      *   -delay.
1390      *
1391      *   For decoding, this is the number of samples the decoder needs to
1392      *   output before the decoder's output is valid. When seeking, you should
1393      *   start decoding this many samples prior to your desired seek point.
1394      *
1395      * - encoding: Set by libavcodec.
1396      * - decoding: Set by libavcodec.
1397      */
1398     int delay;
1399 
1400 
1401     /* video only */
1402     /**
1403      * picture width / height.
1404      * - encoding: MUST be set by user.
1405      * - decoding: May be set by the user before opening the decoder if known e.g.
1406      *             from the container. Some decoders will require the dimensions
1407      *             to be set by the caller. During decoding, the decoder may
1408      *             overwrite those values as required.
1409      */
1410     int width, height;
1411 
1412     /**
1413      * Bitstream width / height, may be different from width/height e.g. when
1414      * the decoded frame is cropped before being output or lowres is enabled.
1415      * - encoding: unused
1416      * - decoding: May be set by the user before opening the decoder if known
1417      *             e.g. from the container. During decoding, the decoder may
1418      *             overwrite those values as required.
1419      */
1420     int coded_width, coded_height;
1421 
1422 #if FF_API_ASPECT_EXTENDED
1423 #define FF_ASPECT_EXTENDED 15
1424 #endif
1425 
1426     /**
1427      * the number of pictures in a group of pictures, or 0 for intra_only
1428      * - encoding: Set by user.
1429      * - decoding: unused
1430      */
1431     int gop_size;
1432 
1433     /**
1434      * Pixel format, see AV_PIX_FMT_xxx.
1435      * May be set by the demuxer if known from headers.
1436      * May be overridden by the decoder if it knows better.
1437      * - encoding: Set by user.
1438      * - decoding: Set by user if known, overridden by libavcodec if known
1439      */
1440     enum AVPixelFormat pix_fmt;
1441 
1442     /**
1443      * Motion estimation algorithm used for video coding.
1444      * 1 (zero), 2 (full), 3 (log), 4 (phods), 5 (epzs), 6 (x1), 7 (hex),
1445      * 8 (umh), 9 (iter), 10 (tesa) [7, 8, 10 are x264 specific, 9 is snow specific]
1446      * - encoding: MUST be set by user.
1447      * - decoding: unused
1448      */
1449     int me_method;
1450 
1451     /**
1452      * If non NULL, 'draw_horiz_band' is called by the libavcodec
1453      * decoder to draw a horizontal band. It improves cache usage. Not
1454      * all codecs can do that. You must check the codec capabilities
1455      * beforehand.
1456      * When multithreading is used, it may be called from multiple threads
1457      * at the same time; threads might draw different parts of the same AVFrame,
1458      * or multiple AVFrames, and there is no guarantee that slices will be drawn
1459      * in order.
1460      * The function is also used by hardware acceleration APIs.
1461      * It is called at least once during frame decoding to pass
1462      * the data needed for hardware render.
1463      * In that mode instead of pixel data, AVFrame points to
1464      * a structure specific to the acceleration API. The application
1465      * reads the structure and can change some fields to indicate progress
1466      * or mark state.
1467      * - encoding: unused
1468      * - decoding: Set by user.
1469      * @param height the height of the slice
1470      * @param y the y position of the slice
1471      * @param type 1->top field, 2->bottom field, 3->frame
1472      * @param offset offset into the AVFrame.data from which the slice should be read
1473      */
1474     void (*draw_horiz_band)(struct AVCodecContext *s,
1475                             const AVFrame *src, int offset[AV_NUM_DATA_POINTERS],
1476                             int y, int type, int height);
1477 
1478     /**
1479      * callback to negotiate the pixelFormat
1480      * @param fmt is the list of formats which are supported by the codec,
1481      * it is terminated by -1 as 0 is a valid format, the formats are ordered by quality.
1482      * The first is always the native one.
1483      * @return the chosen format
1484      * - encoding: unused
1485      * - decoding: Set by user, if not set the native format will be chosen.
1486      */
1487     enum AVPixelFormat (*get_format)(struct AVCodecContext *s, const enum AVPixelFormat * fmt);
1488 
1489     /**
1490      * maximum number of B-frames between non-B-frames
1491      * Note: The output will be delayed by max_b_frames+1 relative to the input.
1492      * - encoding: Set by user.
1493      * - decoding: unused
1494      */
1495     int max_b_frames;
1496 
1497     /**
1498      * qscale factor between IP and B-frames
1499      * If > 0 then the last P-frame quantizer will be used (q= lastp_q*factor+offset).
1500      * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1501      * - encoding: Set by user.
1502      * - decoding: unused
1503      */
1504     float b_quant_factor;
1505 
1506     /** obsolete FIXME remove */
1507     int rc_strategy;
1508 #define FF_RC_STRATEGY_XVID 1
1509 
1510     int b_frame_strategy;
1511 
1512     /**
1513      * qscale offset between IP and B-frames
1514      * - encoding: Set by user.
1515      * - decoding: unused
1516      */
1517     float b_quant_offset;
1518 
1519     /**
1520      * Size of the frame reordering buffer in the decoder.
1521      * For MPEG-2 it is 1 IPB or 0 low delay IP.
1522      * - encoding: Set by libavcodec.
1523      * - decoding: Set by libavcodec.
1524      */
1525     int has_b_frames;
1526 
1527     /**
1528      * 0-> h263 quant 1-> mpeg quant
1529      * - encoding: Set by user.
1530      * - decoding: unused
1531      */
1532     int mpeg_quant;
1533 
1534     /**
1535      * qscale factor between P and I-frames
1536      * If > 0 then the last p frame quantizer will be used (q= lastp_q*factor+offset).
1537      * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1538      * - encoding: Set by user.
1539      * - decoding: unused
1540      */
1541     float i_quant_factor;
1542 
1543     /**
1544      * qscale offset between P and I-frames
1545      * - encoding: Set by user.
1546      * - decoding: unused
1547      */
1548     float i_quant_offset;
1549 
1550     /**
1551      * luminance masking (0-> disabled)
1552      * - encoding: Set by user.
1553      * - decoding: unused
1554      */
1555     float lumi_masking;
1556 
1557     /**
1558      * temporary complexity masking (0-> disabled)
1559      * - encoding: Set by user.
1560      * - decoding: unused
1561      */
1562     float temporal_cplx_masking;
1563 
1564     /**
1565      * spatial complexity masking (0-> disabled)
1566      * - encoding: Set by user.
1567      * - decoding: unused
1568      */
1569     float spatial_cplx_masking;
1570 
1571     /**
1572      * p block masking (0-> disabled)
1573      * - encoding: Set by user.
1574      * - decoding: unused
1575      */
1576     float p_masking;
1577 
1578     /**
1579      * darkness masking (0-> disabled)
1580      * - encoding: Set by user.
1581      * - decoding: unused
1582      */
1583     float dark_masking;
1584 
1585     /**
1586      * slice count
1587      * - encoding: Set by libavcodec.
1588      * - decoding: Set by user (or 0).
1589      */
1590     int slice_count;
1591     /**
1592      * prediction method (needed for huffyuv)
1593      * - encoding: Set by user.
1594      * - decoding: unused
1595      */
1596      int prediction_method;
1597 #define FF_PRED_LEFT   0
1598 #define FF_PRED_PLANE  1
1599 #define FF_PRED_MEDIAN 2
1600 
1601     /**
1602      * slice offsets in the frame in bytes
1603      * - encoding: Set/allocated by libavcodec.
1604      * - decoding: Set/allocated by user (or NULL).
1605      */
1606     int *slice_offset;
1607 
1608     /**
1609      * sample aspect ratio (0 if unknown)
1610      * That is the width of a pixel divided by the height of the pixel.
1611      * Numerator and denominator must be relatively prime and smaller than 256 for some video standards.
1612      * - encoding: Set by user.
1613      * - decoding: Set by libavcodec.
1614      */
1615     AVRational sample_aspect_ratio;
1616 
1617     /**
1618      * motion estimation comparison function
1619      * - encoding: Set by user.
1620      * - decoding: unused
1621      */
1622     int me_cmp;
1623     /**
1624      * subpixel motion estimation comparison function
1625      * - encoding: Set by user.
1626      * - decoding: unused
1627      */
1628     int me_sub_cmp;
1629     /**
1630      * macroblock comparison function (not supported yet)
1631      * - encoding: Set by user.
1632      * - decoding: unused
1633      */
1634     int mb_cmp;
1635     /**
1636      * interlaced DCT comparison function
1637      * - encoding: Set by user.
1638      * - decoding: unused
1639      */
1640     int ildct_cmp;
1641 #define FF_CMP_SAD    0
1642 #define FF_CMP_SSE    1
1643 #define FF_CMP_SATD   2
1644 #define FF_CMP_DCT    3
1645 #define FF_CMP_PSNR   4
1646 #define FF_CMP_BIT    5
1647 #define FF_CMP_RD     6
1648 #define FF_CMP_ZERO   7
1649 #define FF_CMP_VSAD   8
1650 #define FF_CMP_VSSE   9
1651 #define FF_CMP_NSSE   10
1652 #define FF_CMP_W53    11
1653 #define FF_CMP_W97    12
1654 #define FF_CMP_DCTMAX 13
1655 #define FF_CMP_DCT264 14
1656 #define FF_CMP_CHROMA 256
1657 
1658     /**
1659      * ME diamond size & shape
1660      * - encoding: Set by user.
1661      * - decoding: unused
1662      */
1663     int dia_size;
1664 
1665     /**
1666      * amount of previous MV predictors (2a+1 x 2a+1 square)
1667      * - encoding: Set by user.
1668      * - decoding: unused
1669      */
1670     int last_predictor_count;
1671 
1672     /**
1673      * prepass for motion estimation
1674      * - encoding: Set by user.
1675      * - decoding: unused
1676      */
1677     int pre_me;
1678 
1679     /**
1680      * motion estimation prepass comparison function
1681      * - encoding: Set by user.
1682      * - decoding: unused
1683      */
1684     int me_pre_cmp;
1685 
1686     /**
1687      * ME prepass diamond size & shape
1688      * - encoding: Set by user.
1689      * - decoding: unused
1690      */
1691     int pre_dia_size;
1692 
1693     /**
1694      * subpel ME quality
1695      * - encoding: Set by user.
1696      * - decoding: unused
1697      */
1698     int me_subpel_quality;
1699 
1700 #if FF_API_AFD
1701     /**
1702      * DTG active format information (additional aspect ratio
1703      * information only used in DVB MPEG-2 transport streams)
1704      * 0 if not set.
1705      *
1706      * - encoding: unused
1707      * - decoding: Set by decoder.
1708      * @deprecated Deprecated in favor of AVSideData
1709      */
1710     attribute_deprecated int dtg_active_format;
1711 #define FF_DTG_AFD_SAME         8
1712 #define FF_DTG_AFD_4_3          9
1713 #define FF_DTG_AFD_16_9         10
1714 #define FF_DTG_AFD_14_9         11
1715 #define FF_DTG_AFD_4_3_SP_14_9  13
1716 #define FF_DTG_AFD_16_9_SP_14_9 14
1717 #define FF_DTG_AFD_SP_4_3       15
1718 #endif /* FF_API_AFD */
1719 
1720     /**
1721      * maximum motion estimation search range in subpel units
1722      * If 0 then no limit.
1723      *
1724      * - encoding: Set by user.
1725      * - decoding: unused
1726      */
1727     int me_range;
1728 
1729     /**
1730      * intra quantizer bias
1731      * - encoding: Set by user.
1732      * - decoding: unused
1733      */
1734     int intra_quant_bias;
1735 #define FF_DEFAULT_QUANT_BIAS 999999
1736 
1737     /**
1738      * inter quantizer bias
1739      * - encoding: Set by user.
1740      * - decoding: unused
1741      */
1742     int inter_quant_bias;
1743 
1744     /**
1745      * slice flags
1746      * - encoding: unused
1747      * - decoding: Set by user.
1748      */
1749     int slice_flags;
1750 #define SLICE_FLAG_CODED_ORDER    0x0001 ///< draw_horiz_band() is called in coded order instead of display
1751 #define SLICE_FLAG_ALLOW_FIELD    0x0002 ///< allow draw_horiz_band() with field slices (MPEG2 field pics)
1752 #define SLICE_FLAG_ALLOW_PLANE    0x0004 ///< allow draw_horiz_band() with 1 component at a time (SVQ1)
1753 
1754 #if FF_API_XVMC
1755     /**
1756      * XVideo Motion Acceleration
1757      * - encoding: forbidden
1758      * - decoding: set by decoder
1759      * @deprecated XvMC doesn't need it anymore.
1760      */
1761     attribute_deprecated int xvmc_acceleration;
1762 #endif /* FF_API_XVMC */
1763 
1764     /**
1765      * macroblock decision mode
1766      * - encoding: Set by user.
1767      * - decoding: unused
1768      */
1769     int mb_decision;
1770 #define FF_MB_DECISION_SIMPLE 0        ///< uses mb_cmp
1771 #define FF_MB_DECISION_BITS   1        ///< chooses the one which needs the fewest bits
1772 #define FF_MB_DECISION_RD     2        ///< rate distortion
1773 
1774     /**
1775      * custom intra quantization matrix
1776      * - encoding: Set by user, can be NULL.
1777      * - decoding: Set by libavcodec.
1778      */
1779     uint16_t *intra_matrix;
1780 
1781     /**
1782      * custom inter quantization matrix
1783      * - encoding: Set by user, can be NULL.
1784      * - decoding: Set by libavcodec.
1785      */
1786     uint16_t *inter_matrix;
1787 
1788     /**
1789      * scene change detection threshold
1790      * 0 is default, larger means fewer detected scene changes.
1791      * - encoding: Set by user.
1792      * - decoding: unused
1793      */
1794     int scenechange_threshold;
1795 
1796     /**
1797      * noise reduction strength
1798      * - encoding: Set by user.
1799      * - decoding: unused
1800      */
1801     int noise_reduction;
1802 
1803     /**
1804      * Motion estimation threshold below which no motion estimation is
1805      * performed, but instead the user specified motion vectors are used.
1806      *
1807      * - encoding: Set by user.
1808      * - decoding: unused
1809      */
1810     int me_threshold;
1811 
1812     /**
1813      * Macroblock threshold below which the user specified macroblock types will be used.
1814      * - encoding: Set by user.
1815      * - decoding: unused
1816      */
1817     int mb_threshold;
1818 
1819     /**
1820      * precision of the intra DC coefficient - 8
1821      * - encoding: Set by user.
1822      * - decoding: unused
1823      */
1824     int intra_dc_precision;
1825 
1826     /**
1827      * Number of macroblock rows at the top which are skipped.
1828      * - encoding: unused
1829      * - decoding: Set by user.
1830      */
1831     int skip_top;
1832 
1833     /**
1834      * Number of macroblock rows at the bottom which are skipped.
1835      * - encoding: unused
1836      * - decoding: Set by user.
1837      */
1838     int skip_bottom;
1839 
1840     /**
1841      * Border processing masking, raises the quantizer for mbs on the borders
1842      * of the picture.
1843      * - encoding: Set by user.
1844      * - decoding: unused
1845      */
1846     float border_masking;
1847 
1848     /**
1849      * minimum MB lagrange multipler
1850      * - encoding: Set by user.
1851      * - decoding: unused
1852      */
1853     int mb_lmin;
1854 
1855     /**
1856      * maximum MB lagrange multipler
1857      * - encoding: Set by user.
1858      * - decoding: unused
1859      */
1860     int mb_lmax;
1861 
1862     /**
1863      *
1864      * - encoding: Set by user.
1865      * - decoding: unused
1866      */
1867     int me_penalty_compensation;
1868 
1869     /**
1870      *
1871      * - encoding: Set by user.
1872      * - decoding: unused
1873      */
1874     int bidir_refine;
1875 
1876     /**
1877      *
1878      * - encoding: Set by user.
1879      * - decoding: unused
1880      */
1881     int brd_scale;
1882 
1883     /**
1884      * minimum GOP size
1885      * - encoding: Set by user.
1886      * - decoding: unused
1887      */
1888     int keyint_min;
1889 
1890     /**
1891      * number of reference frames
1892      * - encoding: Set by user.
1893      * - decoding: Set by lavc.
1894      */
1895     int refs;
1896 
1897     /**
1898      * chroma qp offset from luma
1899      * - encoding: Set by user.
1900      * - decoding: unused
1901      */
1902     int chromaoffset;
1903 
1904 #if FF_API_UNUSED_MEMBERS
1905     /**
1906      * Multiplied by qscale for each frame and added to scene_change_score.
1907      * - encoding: Set by user.
1908      * - decoding: unused
1909      */
1910     attribute_deprecated int scenechange_factor;
1911 #endif
1912 
1913     /**
1914      *
1915      * Note: Value depends upon the compare function used for fullpel ME.
1916      * - encoding: Set by user.
1917      * - decoding: unused
1918      */
1919     int mv0_threshold;
1920 
1921     /**
1922      * Adjust sensitivity of b_frame_strategy 1.
1923      * - encoding: Set by user.
1924      * - decoding: unused
1925      */
1926     int b_sensitivity;
1927 
1928     /**
1929      * Chromaticity coordinates of the source primaries.
1930      * - encoding: Set by user
1931      * - decoding: Set by libavcodec
1932      */
1933     enum AVColorPrimaries color_primaries;
1934 
1935     /**
1936      * Color Transfer Characteristic.
1937      * - encoding: Set by user
1938      * - decoding: Set by libavcodec
1939      */
1940     enum AVColorTransferCharacteristic color_trc;
1941 
1942     /**
1943      * YUV colorspace type.
1944      * - encoding: Set by user
1945      * - decoding: Set by libavcodec
1946      */
1947     enum AVColorSpace colorspace;
1948 
1949     /**
1950      * MPEG vs JPEG YUV range.
1951      * - encoding: Set by user
1952      * - decoding: Set by libavcodec
1953      */
1954     enum AVColorRange color_range;
1955 
1956     /**
1957      * This defines the location of chroma samples.
1958      * - encoding: Set by user
1959      * - decoding: Set by libavcodec
1960      */
1961     enum AVChromaLocation chroma_sample_location;
1962 
1963     /**
1964      * Number of slices.
1965      * Indicates number of picture subdivisions. Used for parallelized
1966      * decoding.
1967      * - encoding: Set by user
1968      * - decoding: unused
1969      */
1970     int slices;
1971 
1972     /** Field order
1973      * - encoding: set by libavcodec
1974      * - decoding: Set by user.
1975      */
1976     enum AVFieldOrder field_order;
1977 
1978     /* audio only */
1979     int sample_rate; ///< samples per second
1980     int channels;    ///< number of audio channels
1981 
1982     /**
1983      * audio sample format
1984      * - encoding: Set by user.
1985      * - decoding: Set by libavcodec.
1986      */
1987     enum AVSampleFormat sample_fmt;  ///< sample format
1988 
1989     /* The following data should not be initialized. */
1990     /**
1991      * Number of samples per channel in an audio frame.
1992      *
1993      * - encoding: set by libavcodec in avcodec_open2(). Each submitted frame
1994      *   except the last must contain exactly frame_size samples per channel.
1995      *   May be 0 when the codec has CODEC_CAP_VARIABLE_FRAME_SIZE set, then the
1996      *   frame size is not restricted.
1997      * - decoding: may be set by some decoders to indicate constant frame size
1998      */
1999     int frame_size;
2000 
2001     /**
2002      * Frame counter, set by libavcodec.
2003      *
2004      * - decoding: total number of frames returned from the decoder so far.
2005      * - encoding: total number of frames passed to the encoder so far.
2006      *
2007      *   @note the counter is not incremented if encoding/decoding resulted in
2008      *   an error.
2009      */
2010     int frame_number;
2011 
2012     /**
2013      * number of bytes per packet if constant and known or 0
2014      * Used by some WAV based audio codecs.
2015      */
2016     int block_align;
2017 
2018     /**
2019      * Audio cutoff bandwidth (0 means "automatic")
2020      * - encoding: Set by user.
2021      * - decoding: unused
2022      */
2023     int cutoff;
2024 
2025 #if FF_API_REQUEST_CHANNELS
2026     /**
2027      * Decoder should decode to this many channels if it can (0 for default)
2028      * - encoding: unused
2029      * - decoding: Set by user.
2030      * @deprecated Deprecated in favor of request_channel_layout.
2031      */
2032     attribute_deprecated int request_channels;
2033 #endif
2034 
2035     /**
2036      * Audio channel layout.
2037      * - encoding: set by user.
2038      * - decoding: set by user, may be overwritten by libavcodec.
2039      */
2040     uint64_t channel_layout;
2041 
2042     /**
2043      * Request decoder to use this channel layout if it can (0 for default)
2044      * - encoding: unused
2045      * - decoding: Set by user.
2046      */
2047     uint64_t request_channel_layout;
2048 
2049     /**
2050      * Type of service that the audio stream conveys.
2051      * - encoding: Set by user.
2052      * - decoding: Set by libavcodec.
2053      */
2054     enum AVAudioServiceType audio_service_type;
2055 
2056     /**
2057      * desired sample format
2058      * - encoding: Not used.
2059      * - decoding: Set by user.
2060      * Decoder will decode to this format if it can.
2061      */
2062     enum AVSampleFormat request_sample_fmt;
2063 
2064 #if FF_API_GET_BUFFER
2065     /**
2066      * Called at the beginning of each frame to get a buffer for it.
2067      *
2068      * The function will set AVFrame.data[], AVFrame.linesize[].
2069      * AVFrame.extended_data[] must also be set, but it should be the same as
2070      * AVFrame.data[] except for planar audio with more channels than can fit
2071      * in AVFrame.data[]. In that case, AVFrame.data[] shall still contain as
2072      * many data pointers as it can hold.
2073      *
2074      * if CODEC_CAP_DR1 is not set then get_buffer() must call
2075      * avcodec_default_get_buffer() instead of providing buffers allocated by
2076      * some other means.
2077      *
2078      * AVFrame.data[] should be 32- or 16-byte-aligned unless the CPU doesn't
2079      * need it. avcodec_default_get_buffer() aligns the output buffer properly,
2080      * but if get_buffer() is overridden then alignment considerations should
2081      * be taken into account.
2082      *
2083      * @see avcodec_default_get_buffer()
2084      *
2085      * Video:
2086      *
2087      * If pic.reference is set then the frame will be read later by libavcodec.
2088      * avcodec_align_dimensions2() should be used to find the required width and
2089      * height, as they normally need to be rounded up to the next multiple of 16.
2090      *
2091      * If frame multithreading is used and thread_safe_callbacks is set,
2092      * it may be called from a different thread, but not from more than one at
2093      * once. Does not need to be reentrant.
2094      *
2095      * @see release_buffer(), reget_buffer()
2096      * @see avcodec_align_dimensions2()
2097      *
2098      * Audio:
2099      *
2100      * Decoders request a buffer of a particular size by setting
2101      * AVFrame.nb_samples prior to calling get_buffer(). The decoder may,
2102      * however, utilize only part of the buffer by setting AVFrame.nb_samples
2103      * to a smaller value in the output frame.
2104      *
2105      * Decoders cannot use the buffer after returning from
2106      * avcodec_decode_audio4(), so they will not call release_buffer(), as it
2107      * is assumed to be released immediately upon return. In some rare cases,
2108      * a decoder may need to call get_buffer() more than once in a single
2109      * call to avcodec_decode_audio4(). In that case, when get_buffer() is
2110      * called again after it has already been called once, the previously
2111      * acquired buffer is assumed to be released at that time and may not be
2112      * reused by the decoder.
2113      *
2114      * As a convenience, av_samples_get_buffer_size() and
2115      * av_samples_fill_arrays() in libavutil may be used by custom get_buffer()
2116      * functions to find the required data size and to fill data pointers and
2117      * linesize. In AVFrame.linesize, only linesize[0] may be set for audio
2118      * since all planes must be the same size.
2119      *
2120      * @see av_samples_get_buffer_size(), av_samples_fill_arrays()
2121      *
2122      * - encoding: unused
2123      * - decoding: Set by libavcodec, user can override.
2124      *
2125      * @deprecated use get_buffer2()
2126      */
2127     attribute_deprecated
2128     int (*get_buffer)(struct AVCodecContext *c, AVFrame *pic);
2129 
2130     /**
2131      * Called to release buffers which were allocated with get_buffer.
2132      * A released buffer can be reused in get_buffer().
2133      * pic.data[*] must be set to NULL.
2134      * May be called from a different thread if frame multithreading is used,
2135      * but not by more than one thread at once, so does not need to be reentrant.
2136      * - encoding: unused
2137      * - decoding: Set by libavcodec, user can override.
2138      *
2139      * @deprecated custom freeing callbacks should be set from get_buffer2()
2140      */
2141     attribute_deprecated
2142     void (*release_buffer)(struct AVCodecContext *c, AVFrame *pic);
2143 
2144     /**
2145      * Called at the beginning of a frame to get cr buffer for it.
2146      * Buffer type (size, hints) must be the same. libavcodec won't check it.
2147      * libavcodec will pass previous buffer in pic, function should return
2148      * same buffer or new buffer with old frame "painted" into it.
2149      * If pic.data[0] == NULL must behave like get_buffer().
2150      * if CODEC_CAP_DR1 is not set then reget_buffer() must call
2151      * avcodec_default_reget_buffer() instead of providing buffers allocated by
2152      * some other means.
2153      * - encoding: unused
2154      * - decoding: Set by libavcodec, user can override.
2155      */
2156     attribute_deprecated
2157     int (*reget_buffer)(struct AVCodecContext *c, AVFrame *pic);
2158 #endif
2159 
2160     /**
2161      * This callback is called at the beginning of each frame to get data
2162      * buffer(s) for it. There may be one contiguous buffer for all the data or
2163      * there may be a buffer per each data plane or anything in between. What
2164      * this means is, you may set however many entries in buf[] you feel necessary.
2165      * Each buffer must be reference-counted using the AVBuffer API (see description
2166      * of buf[] below).
2167      *
2168      * The following fields will be set in the frame before this callback is
2169      * called:
2170      * - format
2171      * - width, height (video only)
2172      * - sample_rate, channel_layout, nb_samples (audio only)
2173      * Their values may differ from the corresponding values in
2174      * AVCodecContext. This callback must use the frame values, not the codec
2175      * context values, to calculate the required buffer size.
2176      *
2177      * This callback must fill the following fields in the frame:
2178      * - data[]
2179      * - linesize[]
2180      * - extended_data:
2181      *   * if the data is planar audio with more than 8 channels, then this
2182      *     callback must allocate and fill extended_data to contain all pointers
2183      *     to all data planes. data[] must hold as many pointers as it can.
2184      *     extended_data must be allocated with av_malloc() and will be freed in
2185      *     av_frame_unref().
2186      *   * otherwise exended_data must point to data
2187      * - buf[] must contain one or more pointers to AVBufferRef structures. Each of
2188      *   the frame's data and extended_data pointers must be contained in these. That
2189      *   is, one AVBufferRef for each allocated chunk of memory, not necessarily one
2190      *   AVBufferRef per data[] entry. See: av_buffer_create(), av_buffer_alloc(),
2191      *   and av_buffer_ref().
2192      * - extended_buf and nb_extended_buf must be allocated with av_malloc() by
2193      *   this callback and filled with the extra buffers if there are more
2194      *   buffers than buf[] can hold. extended_buf will be freed in
2195      *   av_frame_unref().
2196      *
2197      * If CODEC_CAP_DR1 is not set then get_buffer2() must call
2198      * avcodec_default_get_buffer2() instead of providing buffers allocated by
2199      * some other means.
2200      *
2201      * Each data plane must be aligned to the maximum required by the target
2202      * CPU.
2203      *
2204      * @see avcodec_default_get_buffer2()
2205      *
2206      * Video:
2207      *
2208      * If AV_GET_BUFFER_FLAG_REF is set in flags then the frame may be reused
2209      * (read and/or written to if it is writable) later by libavcodec.
2210      *
2211      * avcodec_align_dimensions2() should be used to find the required width and
2212      * height, as they normally need to be rounded up to the next multiple of 16.
2213      *
2214      * Some decoders do not support linesizes changing between frames.
2215      *
2216      * If frame multithreading is used and thread_safe_callbacks is set,
2217      * this callback may be called from a different thread, but not from more
2218      * than one at once. Does not need to be reentrant.
2219      *
2220      * @see avcodec_align_dimensions2()
2221      *
2222      * Audio:
2223      *
2224      * Decoders request a buffer of a particular size by setting
2225      * AVFrame.nb_samples prior to calling get_buffer2(). The decoder may,
2226      * however, utilize only part of the buffer by setting AVFrame.nb_samples
2227      * to a smaller value in the output frame.
2228      *
2229      * As a convenience, av_samples_get_buffer_size() and
2230      * av_samples_fill_arrays() in libavutil may be used by custom get_buffer2()
2231      * functions to find the required data size and to fill data pointers and
2232      * linesize. In AVFrame.linesize, only linesize[0] may be set for audio
2233      * since all planes must be the same size.
2234      *
2235      * @see av_samples_get_buffer_size(), av_samples_fill_arrays()
2236      *
2237      * - encoding: unused
2238      * - decoding: Set by libavcodec, user can override.
2239      */
2240     int (*get_buffer2)(struct AVCodecContext *s, AVFrame *frame, int flags);
2241 
2242     /**
2243      * If non-zero, the decoded audio and video frames returned from
2244      * avcodec_decode_video2() and avcodec_decode_audio4() are reference-counted
2245      * and are valid indefinitely. The caller must free them with
2246      * av_frame_unref() when they are not needed anymore.
2247      * Otherwise, the decoded frames must not be freed by the caller and are
2248      * only valid until the next decode call.
2249      *
2250      * - encoding: unused
2251      * - decoding: set by the caller before avcodec_open2().
2252      */
2253     int refcounted_frames;
2254 
2255     /* - encoding parameters */
2256     float qcompress;  ///< amount of qscale change between easy & hard scenes (0.0-1.0)
2257     float qblur;      ///< amount of qscale smoothing over time (0.0-1.0)
2258 
2259     /**
2260      * minimum quantizer
2261      * - encoding: Set by user.
2262      * - decoding: unused
2263      */
2264     int qmin;
2265 
2266     /**
2267      * maximum quantizer
2268      * - encoding: Set by user.
2269      * - decoding: unused
2270      */
2271     int qmax;
2272 
2273     /**
2274      * maximum quantizer difference between frames
2275      * - encoding: Set by user.
2276      * - decoding: unused
2277      */
2278     int max_qdiff;
2279 
2280     /**
2281      * ratecontrol qmin qmax limiting method
2282      * 0-> clipping, 1-> use a nice continuous function to limit qscale within qmin/qmax.
2283      * - encoding: Set by user.
2284      * - decoding: unused
2285      */
2286     float rc_qsquish;
2287 
2288     float rc_qmod_amp;
2289     int rc_qmod_freq;
2290 
2291     /**
2292      * decoder bitstream buffer size
2293      * - encoding: Set by user.
2294      * - decoding: unused
2295      */
2296     int rc_buffer_size;
2297 
2298     /**
2299      * ratecontrol override, see RcOverride
2300      * - encoding: Allocated/set/freed by user.
2301      * - decoding: unused
2302      */
2303     int rc_override_count;
2304     RcOverride *rc_override;
2305 
2306     /**
2307      * rate control equation
2308      * - encoding: Set by user
2309      * - decoding: unused
2310      */
2311     const char *rc_eq;
2312 
2313     /**
2314      * maximum bitrate
2315      * - encoding: Set by user.
2316      * - decoding: Set by libavcodec.
2317      */
2318     int rc_max_rate;
2319 
2320     /**
2321      * minimum bitrate
2322      * - encoding: Set by user.
2323      * - decoding: unused
2324      */
2325     int rc_min_rate;
2326 
2327     float rc_buffer_aggressivity;
2328 
2329     /**
2330      * initial complexity for pass1 ratecontrol
2331      * - encoding: Set by user.
2332      * - decoding: unused
2333      */
2334     float rc_initial_cplx;
2335 
2336     /**
2337      * Ratecontrol attempt to use, at maximum, <value> of what can be used without an underflow.
2338      * - encoding: Set by user.
2339      * - decoding: unused.
2340      */
2341     float rc_max_available_vbv_use;
2342 
2343     /**
2344      * Ratecontrol attempt to use, at least, <value> times the amount needed to prevent a vbv overflow.
2345      * - encoding: Set by user.
2346      * - decoding: unused.
2347      */
2348     float rc_min_vbv_overflow_use;
2349 
2350     /**
2351      * Number of bits which should be loaded into the rc buffer before decoding starts.
2352      * - encoding: Set by user.
2353      * - decoding: unused
2354      */
2355     int rc_initial_buffer_occupancy;
2356 
2357 #define FF_CODER_TYPE_VLC       0
2358 #define FF_CODER_TYPE_AC        1
2359 #define FF_CODER_TYPE_RAW       2
2360 #define FF_CODER_TYPE_RLE       3
2361 #if FF_API_UNUSED_MEMBERS
2362 #define FF_CODER_TYPE_DEFLATE   4
2363 #endif /* FF_API_UNUSED_MEMBERS */
2364     /**
2365      * coder type
2366      * - encoding: Set by user.
2367      * - decoding: unused
2368      */
2369     int coder_type;
2370 
2371     /**
2372      * context model
2373      * - encoding: Set by user.
2374      * - decoding: unused
2375      */
2376     int context_model;
2377 
2378     /**
2379      * minimum Lagrange multiplier
2380      * - encoding: Set by user.
2381      * - decoding: unused
2382      */
2383     int lmin;
2384 
2385     /**
2386      * maximum Lagrange multiplier
2387      * - encoding: Set by user.
2388      * - decoding: unused
2389      */
2390     int lmax;
2391 
2392     /**
2393      * frame skip threshold
2394      * - encoding: Set by user.
2395      * - decoding: unused
2396      */
2397     int frame_skip_threshold;
2398 
2399     /**
2400      * frame skip factor
2401      * - encoding: Set by user.
2402      * - decoding: unused
2403      */
2404     int frame_skip_factor;
2405 
2406     /**
2407      * frame skip exponent
2408      * - encoding: Set by user.
2409      * - decoding: unused
2410      */
2411     int frame_skip_exp;
2412 
2413     /**
2414      * frame skip comparison function
2415      * - encoding: Set by user.
2416      * - decoding: unused
2417      */
2418     int frame_skip_cmp;
2419 
2420     /**
2421      * trellis RD quantization
2422      * - encoding: Set by user.
2423      * - decoding: unused
2424      */
2425     int trellis;
2426 
2427     /**
2428      * - encoding: Set by user.
2429      * - decoding: unused
2430      */
2431     int min_prediction_order;
2432 
2433     /**
2434      * - encoding: Set by user.
2435      * - decoding: unused
2436      */
2437     int max_prediction_order;
2438 
2439     /**
2440      * GOP timecode frame start number
2441      * - encoding: Set by user, in non drop frame format
2442      * - decoding: Set by libavcodec (timecode in the 25 bits format, -1 if unset)
2443      */
2444     int64_t timecode_frame_start;
2445 
2446     /* The RTP callback: This function is called    */
2447     /* every time the encoder has a packet to send. */
2448     /* It depends on the encoder if the data starts */
2449     /* with a Start Code (it should). H.263 does.   */
2450     /* mb_nb contains the number of macroblocks     */
2451     /* encoded in the RTP payload.                  */
2452     void (*rtp_callback)(struct AVCodecContext *avctx, void *data, int size, int mb_nb);
2453 
2454     int rtp_payload_size;   /* The size of the RTP payload: the coder will  */
2455                             /* do its best to deliver a chunk with size     */
2456                             /* below rtp_payload_size, the chunk will start */
2457                             /* with a start code on some codecs like H.263. */
2458                             /* This doesn't take account of any particular  */
2459                             /* headers inside the transmitted RTP payload.  */
2460 
2461     /* statistics, used for 2-pass encoding */
2462     int mv_bits;
2463     int header_bits;
2464     int i_tex_bits;
2465     int p_tex_bits;
2466     int i_count;
2467     int p_count;
2468     int skip_count;
2469     int misc_bits;
2470 
2471     /**
2472      * number of bits used for the previously encoded frame
2473      * - encoding: Set by libavcodec.
2474      * - decoding: unused
2475      */
2476     int frame_bits;
2477 
2478     /**
2479      * pass1 encoding statistics output buffer
2480      * - encoding: Set by libavcodec.
2481      * - decoding: unused
2482      */
2483     char *stats_out;
2484 
2485     /**
2486      * pass2 encoding statistics input buffer
2487      * Concatenated stuff from stats_out of pass1 should be placed here.
2488      * - encoding: Allocated/set/freed by user.
2489      * - decoding: unused
2490      */
2491     char *stats_in;
2492 
2493     /**
2494      * Work around bugs in encoders which sometimes cannot be detected automatically.
2495      * - encoding: Set by user
2496      * - decoding: Set by user
2497      */
2498     int workaround_bugs;
2499 #define FF_BUG_AUTODETECT       1  ///< autodetection
2500 #if FF_API_OLD_MSMPEG4
2501 #define FF_BUG_OLD_MSMPEG4      2
2502 #endif
2503 #define FF_BUG_XVID_ILACE       4
2504 #define FF_BUG_UMP4             8
2505 #define FF_BUG_NO_PADDING       16
2506 #define FF_BUG_AMV              32
2507 #if FF_API_AC_VLC
2508 #define FF_BUG_AC_VLC           0  ///< Will be removed, libavcodec can now handle these non-compliant files by default.
2509 #endif
2510 #define FF_BUG_QPEL_CHROMA      64
2511 #define FF_BUG_STD_QPEL         128
2512 #define FF_BUG_QPEL_CHROMA2     256
2513 #define FF_BUG_DIRECT_BLOCKSIZE 512
2514 #define FF_BUG_EDGE             1024
2515 #define FF_BUG_HPEL_CHROMA      2048
2516 #define FF_BUG_DC_CLIP          4096
2517 #define FF_BUG_MS               8192 ///< Work around various bugs in Microsoft's broken decoders.
2518 #define FF_BUG_TRUNCATED       16384
2519 
2520     /**
2521      * strictly follow the standard (MPEG4, ...).
2522      * - encoding: Set by user.
2523      * - decoding: Set by user.
2524      * Setting this to STRICT or higher means the encoder and decoder will
2525      * generally do stupid things, whereas setting it to unofficial or lower
2526      * will mean the encoder might produce output that is not supported by all
2527      * spec-compliant decoders. Decoders don't differentiate between normal,
2528      * unofficial and experimental (that is, they always try to decode things
2529      * when they can) unless they are explicitly asked to behave stupidly
2530      * (=strictly conform to the specs)
2531      */
2532     int strict_std_compliance;
2533 #define FF_COMPLIANCE_VERY_STRICT   2 ///< Strictly conform to an older more strict version of the spec or reference software.
2534 #define FF_COMPLIANCE_STRICT        1 ///< Strictly conform to all the things in the spec no matter what consequences.
2535 #define FF_COMPLIANCE_NORMAL        0
2536 #define FF_COMPLIANCE_UNOFFICIAL   -1 ///< Allow unofficial extensions
2537 #define FF_COMPLIANCE_EXPERIMENTAL -2 ///< Allow nonstandardized experimental things.
2538 
2539     /**
2540      * error concealment flags
2541      * - encoding: unused
2542      * - decoding: Set by user.
2543      */
2544     int error_concealment;
2545 #define FF_EC_GUESS_MVS   1
2546 #define FF_EC_DEBLOCK     2
2547 #define FF_EC_FAVOR_INTER 256
2548 
2549     /**
2550      * debug
2551      * - encoding: Set by user.
2552      * - decoding: Set by user.
2553      */
2554     int debug;
2555 #define FF_DEBUG_PICT_INFO   1
2556 #define FF_DEBUG_RC          2
2557 #define FF_DEBUG_BITSTREAM   4
2558 #define FF_DEBUG_MB_TYPE     8
2559 #define FF_DEBUG_QP          16
2560 #if FF_API_DEBUG_MV
2561 /**
2562  * @deprecated this option does nothing
2563  */
2564 #define FF_DEBUG_MV          32
2565 #endif
2566 #define FF_DEBUG_DCT_COEFF   0x00000040
2567 #define FF_DEBUG_SKIP        0x00000080
2568 #define FF_DEBUG_STARTCODE   0x00000100
2569 #if FF_API_UNUSED_MEMBERS
2570 #define FF_DEBUG_PTS         0x00000200
2571 #endif /* FF_API_UNUSED_MEMBERS */
2572 #define FF_DEBUG_ER          0x00000400
2573 #define FF_DEBUG_MMCO        0x00000800
2574 #define FF_DEBUG_BUGS        0x00001000
2575 #if FF_API_DEBUG_MV
2576 #define FF_DEBUG_VIS_QP      0x00002000 ///< only access through AVOptions from outside libavcodec
2577 #define FF_DEBUG_VIS_MB_TYPE 0x00004000 ///< only access through AVOptions from outside libavcodec
2578 #endif
2579 #define FF_DEBUG_BUFFERS     0x00008000
2580 #define FF_DEBUG_THREADS     0x00010000
2581 #define FF_DEBUG_NOMC        0x01000000
2582 
2583 #if FF_API_DEBUG_MV
2584     /**
2585      * debug
2586      * Code outside libavcodec should access this field using AVOptions
2587      * - encoding: Set by user.
2588      * - decoding: Set by user.
2589      */
2590     int debug_mv;
2591 #define FF_DEBUG_VIS_MV_P_FOR  0x00000001 //visualize forward predicted MVs of P frames
2592 #define FF_DEBUG_VIS_MV_B_FOR  0x00000002 //visualize forward predicted MVs of B frames
2593 #define FF_DEBUG_VIS_MV_B_BACK 0x00000004 //visualize backward predicted MVs of B frames
2594 #endif
2595 
2596     /**
2597      * Error recognition; may misdetect some more or less valid parts as errors.
2598      * - encoding: unused
2599      * - decoding: Set by user.
2600      */
2601     int err_recognition;
2602 
2603 /**
2604  * Verify checksums embedded in the bitstream (could be of either encoded or
2605  * decoded data, depending on the codec) and print an error message on mismatch.
2606  * If AV_EF_EXPLODE is also set, a mismatching checksum will result in the
2607  * decoder returning an error.
2608  */
2609 #define AV_EF_CRCCHECK  (1<<0)
2610 #define AV_EF_BITSTREAM (1<<1)          ///< detect bitstream specification deviations
2611 #define AV_EF_BUFFER    (1<<2)          ///< detect improper bitstream length
2612 #define AV_EF_EXPLODE   (1<<3)          ///< abort decoding on minor error detection
2613 
2614 #define AV_EF_IGNORE_ERR (1<<15)        ///< ignore errors and continue
2615 #define AV_EF_CAREFUL    (1<<16)        ///< consider things that violate the spec, are fast to calculate and have not been seen in the wild as errors
2616 #define AV_EF_COMPLIANT  (1<<17)        ///< consider all spec non compliances as errors
2617 #define AV_EF_AGGRESSIVE (1<<18)        ///< consider things that a sane encoder should not do as an error
2618 
2619 
2620     /**
2621      * opaque 64bit number (generally a PTS) that will be reordered and
2622      * output in AVFrame.reordered_opaque
2623      * - encoding: unused
2624      * - decoding: Set by user.
2625      */
2626     int64_t reordered_opaque;
2627 
2628     /**
2629      * Hardware accelerator in use
2630      * - encoding: unused.
2631      * - decoding: Set by libavcodec
2632      */
2633     struct AVHWAccel *hwaccel;
2634 
2635     /**
2636      * Hardware accelerator context.
2637      * For some hardware accelerators, a global context needs to be
2638      * provided by the user. In that case, this holds display-dependent
2639      * data FFmpeg cannot instantiate itself. Please refer to the
2640      * FFmpeg HW accelerator documentation to know how to fill this
2641      * is. e.g. for VA API, this is a struct vaapi_context.
2642      * - encoding: unused
2643      * - decoding: Set by user
2644      */
2645     void *hwaccel_context;
2646 
2647     /**
2648      * error
2649      * - encoding: Set by libavcodec if flags&CODEC_FLAG_PSNR.
2650      * - decoding: unused
2651      */
2652     uint64_t error[AV_NUM_DATA_POINTERS];
2653 
2654     /**
2655      * DCT algorithm, see FF_DCT_* below
2656      * - encoding: Set by user.
2657      * - decoding: unused
2658      */
2659     int dct_algo;
2660 #define FF_DCT_AUTO    0
2661 #define FF_DCT_FASTINT 1
2662 #if FF_API_UNUSED_MEMBERS
2663 #define FF_DCT_INT     2
2664 #endif /* FF_API_UNUSED_MEMBERS */
2665 #define FF_DCT_MMX     3
2666 #define FF_DCT_ALTIVEC 5
2667 #define FF_DCT_FAAN    6
2668 
2669     /**
2670      * IDCT algorithm, see FF_IDCT_* below.
2671      * - encoding: Set by user.
2672      * - decoding: Set by user.
2673      */
2674     int idct_algo;
2675 #define FF_IDCT_AUTO          0
2676 #define FF_IDCT_INT           1
2677 #define FF_IDCT_SIMPLE        2
2678 #define FF_IDCT_SIMPLEMMX     3
2679 #define FF_IDCT_ARM           7
2680 #define FF_IDCT_ALTIVEC       8
2681 #if FF_API_ARCH_SH4
2682 #define FF_IDCT_SH4           9
2683 #endif
2684 #define FF_IDCT_SIMPLEARM     10
2685 #if FF_API_UNUSED_MEMBERS
2686 #define FF_IDCT_IPP           13
2687 #endif /* FF_API_UNUSED_MEMBERS */
2688 #define FF_IDCT_XVID          14
2689 #if FF_API_IDCT_XVIDMMX
2690 #define FF_IDCT_XVIDMMX       14
2691 #endif /* FF_API_IDCT_XVIDMMX */
2692 #define FF_IDCT_SIMPLEARMV5TE 16
2693 #define FF_IDCT_SIMPLEARMV6   17
2694 #if FF_API_ARCH_SPARC
2695 #define FF_IDCT_SIMPLEVIS     18
2696 #endif
2697 #define FF_IDCT_FAAN          20
2698 #define FF_IDCT_SIMPLENEON    22
2699 #if FF_API_ARCH_ALPHA
2700 #define FF_IDCT_SIMPLEALPHA   23
2701 #endif
2702 #define FF_IDCT_SIMPLEAUTO    128
2703 
2704     /**
2705      * bits per sample/pixel from the demuxer (needed for huffyuv).
2706      * - encoding: Set by libavcodec.
2707      * - decoding: Set by user.
2708      */
2709      int bits_per_coded_sample;
2710 
2711     /**
2712      * Bits per sample/pixel of internal libavcodec pixel/sample format.
2713      * - encoding: set by user.
2714      * - decoding: set by libavcodec.
2715      */
2716     int bits_per_raw_sample;
2717 
2718 #if FF_API_LOWRES
2719     /**
2720      * low resolution decoding, 1-> 1/2 size, 2->1/4 size
2721      * - encoding: unused
2722      * - decoding: Set by user.
2723      * Code outside libavcodec should access this field using:
2724      * av_codec_{get,set}_lowres(avctx)
2725      */
2726      int lowres;
2727 #endif
2728 
2729     /**
2730      * the picture in the bitstream
2731      * - encoding: Set by libavcodec.
2732      * - decoding: unused
2733      */
2734     AVFrame *coded_frame;
2735 
2736     /**
2737      * thread count
2738      * is used to decide how many independent tasks should be passed to execute()
2739      * - encoding: Set by user.
2740      * - decoding: Set by user.
2741      */
2742     int thread_count;
2743 
2744     /**
2745      * Which multithreading methods to use.
2746      * Use of FF_THREAD_FRAME will increase decoding delay by one frame per thread,
2747      * so clients which cannot provide future frames should not use it.
2748      *
2749      * - encoding: Set by user, otherwise the default is used.
2750      * - decoding: Set by user, otherwise the default is used.
2751      */
2752     int thread_type;
2753 #define FF_THREAD_FRAME   1 ///< Decode more than one frame at once
2754 #define FF_THREAD_SLICE   2 ///< Decode more than one part of a single frame at once
2755 
2756     /**
2757      * Which multithreading methods are in use by the codec.
2758      * - encoding: Set by libavcodec.
2759      * - decoding: Set by libavcodec.
2760      */
2761     int active_thread_type;
2762 
2763     /**
2764      * Set by the client if its custom get_buffer() callback can be called
2765      * synchronously from another thread, which allows faster multithreaded decoding.
2766      * draw_horiz_band() will be called from other threads regardless of this setting.
2767      * Ignored if the default get_buffer() is used.
2768      * - encoding: Set by user.
2769      * - decoding: Set by user.
2770      */
2771     int thread_safe_callbacks;
2772 
2773     /**
2774      * The codec may call this to execute several independent things.
2775      * It will return only after finishing all tasks.
2776      * The user may replace this with some multithreaded implementation,
2777      * the default implementation will execute the parts serially.
2778      * @param count the number of things to execute
2779      * - encoding: Set by libavcodec, user can override.
2780      * - decoding: Set by libavcodec, user can override.
2781      */
2782     int (*execute)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size);
2783 
2784     /**
2785      * The codec may call this to execute several independent things.
2786      * It will return only after finishing all tasks.
2787      * The user may replace this with some multithreaded implementation,
2788      * the default implementation will execute the parts serially.
2789      * Also see avcodec_thread_init and e.g. the --enable-pthread configure option.
2790      * @param c context passed also to func
2791      * @param count the number of things to execute
2792      * @param arg2 argument passed unchanged to func
2793      * @param ret return values of executed functions, must have space for "count" values. May be NULL.
2794      * @param func function that will be called count times, with jobnr from 0 to count-1.
2795      *             threadnr will be in the range 0 to c->thread_count-1 < MAX_THREADS and so that no
2796      *             two instances of func executing at the same time will have the same threadnr.
2797      * @return always 0 currently, but code should handle a future improvement where when any call to func
2798      *         returns < 0 no further calls to func may be done and < 0 is returned.
2799      * - encoding: Set by libavcodec, user can override.
2800      * - decoding: Set by libavcodec, user can override.
2801      */
2802     int (*execute2)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count);
2803 
2804 #if FF_API_THREAD_OPAQUE
2805     /**
2806      * @deprecated this field should not be used from outside of lavc
2807      */
2808     attribute_deprecated
2809     void *thread_opaque;
2810 #endif
2811 
2812     /**
2813      * noise vs. sse weight for the nsse comparison function
2814      * - encoding: Set by user.
2815      * - decoding: unused
2816      */
2817      int nsse_weight;
2818 
2819     /**
2820      * profile
2821      * - encoding: Set by user.
2822      * - decoding: Set by libavcodec.
2823      */
2824      int profile;
2825 #define FF_PROFILE_UNKNOWN -99
2826 #define FF_PROFILE_RESERVED -100
2827 
2828 #define FF_PROFILE_AAC_MAIN 0
2829 #define FF_PROFILE_AAC_LOW  1
2830 #define FF_PROFILE_AAC_SSR  2
2831 #define FF_PROFILE_AAC_LTP  3
2832 #define FF_PROFILE_AAC_HE   4
2833 #define FF_PROFILE_AAC_HE_V2 28
2834 #define FF_PROFILE_AAC_LD   22
2835 #define FF_PROFILE_AAC_ELD  38
2836 #define FF_PROFILE_MPEG2_AAC_LOW 128
2837 #define FF_PROFILE_MPEG2_AAC_HE  131
2838 
2839 #define FF_PROFILE_DTS         20
2840 #define FF_PROFILE_DTS_ES      30
2841 #define FF_PROFILE_DTS_96_24   40
2842 #define FF_PROFILE_DTS_HD_HRA  50
2843 #define FF_PROFILE_DTS_HD_MA   60
2844 
2845 #define FF_PROFILE_MPEG2_422    0
2846 #define FF_PROFILE_MPEG2_HIGH   1
2847 #define FF_PROFILE_MPEG2_SS     2
2848 #define FF_PROFILE_MPEG2_SNR_SCALABLE  3
2849 #define FF_PROFILE_MPEG2_MAIN   4
2850 #define FF_PROFILE_MPEG2_SIMPLE 5
2851 
2852 #define FF_PROFILE_H264_CONSTRAINED  (1<<9)  // 8+1; constraint_set1_flag
2853 #define FF_PROFILE_H264_INTRA        (1<<11) // 8+3; constraint_set3_flag
2854 
2855 #define FF_PROFILE_H264_BASELINE             66
2856 #define FF_PROFILE_H264_CONSTRAINED_BASELINE (66|FF_PROFILE_H264_CONSTRAINED)
2857 #define FF_PROFILE_H264_MAIN                 77
2858 #define FF_PROFILE_H264_EXTENDED             88
2859 #define FF_PROFILE_H264_HIGH                 100
2860 #define FF_PROFILE_H264_HIGH_10              110
2861 #define FF_PROFILE_H264_HIGH_10_INTRA        (110|FF_PROFILE_H264_INTRA)
2862 #define FF_PROFILE_H264_HIGH_422             122
2863 #define FF_PROFILE_H264_HIGH_422_INTRA       (122|FF_PROFILE_H264_INTRA)
2864 #define FF_PROFILE_H264_HIGH_444             144
2865 #define FF_PROFILE_H264_HIGH_444_PREDICTIVE  244
2866 #define FF_PROFILE_H264_HIGH_444_INTRA       (244|FF_PROFILE_H264_INTRA)
2867 #define FF_PROFILE_H264_CAVLC_444            44
2868 
2869 #define FF_PROFILE_VC1_SIMPLE   0
2870 #define FF_PROFILE_VC1_MAIN     1
2871 #define FF_PROFILE_VC1_COMPLEX  2
2872 #define FF_PROFILE_VC1_ADVANCED 3
2873 
2874 #define FF_PROFILE_MPEG4_SIMPLE                     0
2875 #define FF_PROFILE_MPEG4_SIMPLE_SCALABLE            1
2876 #define FF_PROFILE_MPEG4_CORE                       2
2877 #define FF_PROFILE_MPEG4_MAIN                       3
2878 #define FF_PROFILE_MPEG4_N_BIT                      4
2879 #define FF_PROFILE_MPEG4_SCALABLE_TEXTURE           5
2880 #define FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION      6
2881 #define FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE     7
2882 #define FF_PROFILE_MPEG4_HYBRID                     8
2883 #define FF_PROFILE_MPEG4_ADVANCED_REAL_TIME         9
2884 #define FF_PROFILE_MPEG4_CORE_SCALABLE             10
2885 #define FF_PROFILE_MPEG4_ADVANCED_CODING           11
2886 #define FF_PROFILE_MPEG4_ADVANCED_CORE             12
2887 #define FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE 13
2888 #define FF_PROFILE_MPEG4_SIMPLE_STUDIO             14
2889 #define FF_PROFILE_MPEG4_ADVANCED_SIMPLE           15
2890 
2891 #define FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_0   0
2892 #define FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_1   1
2893 #define FF_PROFILE_JPEG2000_CSTREAM_NO_RESTRICTION  2
2894 #define FF_PROFILE_JPEG2000_DCINEMA_2K              3
2895 #define FF_PROFILE_JPEG2000_DCINEMA_4K              4
2896 
2897 
2898 #define FF_PROFILE_HEVC_MAIN                        1
2899 #define FF_PROFILE_HEVC_MAIN_10                     2
2900 #define FF_PROFILE_HEVC_MAIN_STILL_PICTURE          3
2901 #define FF_PROFILE_HEVC_REXT                        4
2902 
2903     /**
2904      * level
2905      * - encoding: Set by user.
2906      * - decoding: Set by libavcodec.
2907      */
2908      int level;
2909 #define FF_LEVEL_UNKNOWN -99
2910 
2911     /**
2912      * Skip loop filtering for selected frames.
2913      * - encoding: unused
2914      * - decoding: Set by user.
2915      */
2916     enum AVDiscard skip_loop_filter;
2917 
2918     /**
2919      * Skip IDCT/dequantization for selected frames.
2920      * - encoding: unused
2921      * - decoding: Set by user.
2922      */
2923     enum AVDiscard skip_idct;
2924 
2925     /**
2926      * Skip decoding for selected frames.
2927      * - encoding: unused
2928      * - decoding: Set by user.
2929      */
2930     enum AVDiscard skip_frame;
2931 
2932     /**
2933      * Header containing style information for text subtitles.
2934      * For SUBTITLE_ASS subtitle type, it should contain the whole ASS
2935      * [Script Info] and [V4+ Styles] section, plus the [Events] line and
2936      * the Format line following. It shouldn't include any Dialogue line.
2937      * - encoding: Set/allocated/freed by user (before avcodec_open2())
2938      * - decoding: Set/allocated/freed by libavcodec (by avcodec_open2())
2939      */
2940     uint8_t *subtitle_header;
2941     int subtitle_header_size;
2942 
2943 #if FF_API_ERROR_RATE
2944     /**
2945      * @deprecated use the 'error_rate' private AVOption of the mpegvideo
2946      * encoders
2947      */
2948     attribute_deprecated
2949     int error_rate;
2950 #endif
2951 
2952 #if FF_API_CODEC_PKT
2953     /**
2954      * @deprecated this field is not supposed to be accessed from outside lavc
2955      */
2956     attribute_deprecated
2957     AVPacket *pkt;
2958 #endif
2959 
2960     /**
2961      * VBV delay coded in the last frame (in periods of a 27 MHz clock).
2962      * Used for compliant TS muxing.
2963      * - encoding: Set by libavcodec.
2964      * - decoding: unused.
2965      */
2966     uint64_t vbv_delay;
2967 
2968     /**
2969      * Encoding only. Allow encoders to output packets that do not contain any
2970      * encoded data, only side data.
2971      *
2972      * Some encoders need to output such packets, e.g. to update some stream
2973      * parameters at the end of encoding.
2974      *
2975      * All callers are strongly recommended to set this option to 1 and update
2976      * their code to deal with such packets, since this behaviour may become
2977      * always enabled in the future (then this option will be deprecated and
2978      * later removed). To avoid ABI issues when this happens, the callers should
2979      * use AVOptions to set this field.
2980      */
2981     int side_data_only_packets;
2982 
2983     /**
2984      * Timebase in which pkt_dts/pts and AVPacket.dts/pts are.
2985      * Code outside libavcodec should access this field using:
2986      * av_codec_{get,set}_pkt_timebase(avctx)
2987      * - encoding unused.
2988      * - decoding set by user.
2989      */
2990     AVRational pkt_timebase;
2991 
2992     /**
2993      * AVCodecDescriptor
2994      * Code outside libavcodec should access this field using:
2995      * av_codec_{get,set}_codec_descriptor(avctx)
2996      * - encoding: unused.
2997      * - decoding: set by libavcodec.
2998      */
2999     const AVCodecDescriptor *codec_descriptor;
3000 
3001 #if !FF_API_LOWRES
3002     /**
3003      * low resolution decoding, 1-> 1/2 size, 2->1/4 size
3004      * - encoding: unused
3005      * - decoding: Set by user.
3006      * Code outside libavcodec should access this field using:
3007      * av_codec_{get,set}_lowres(avctx)
3008      */
3009      int lowres;
3010 #endif
3011 
3012     /**
3013      * Current statistics for PTS correction.
3014      * - decoding: maintained and used by libavcodec, not intended to be used by user apps
3015      * - encoding: unused
3016      */
3017     int64_t pts_correction_num_faulty_pts; /// Number of incorrect PTS values so far
3018     int64_t pts_correction_num_faulty_dts; /// Number of incorrect DTS values so far
3019     int64_t pts_correction_last_pts;       /// PTS of the last frame
3020     int64_t pts_correction_last_dts;       /// DTS of the last frame
3021 
3022     /**
3023      * Character encoding of the input subtitles file.
3024      * - decoding: set by user
3025      * - encoding: unused
3026      */
3027     char *sub_charenc;
3028 
3029     /**
3030      * Subtitles character encoding mode. Formats or codecs might be adjusting
3031      * this setting (if they are doing the conversion themselves for instance).
3032      * - decoding: set by libavcodec
3033      * - encoding: unused
3034      */
3035     int sub_charenc_mode;
3036 #define FF_SUB_CHARENC_MODE_DO_NOTHING  -1  ///< do nothing (demuxer outputs a stream supposed to be already in UTF-8, or the codec is bitmap for instance)
3037 #define FF_SUB_CHARENC_MODE_AUTOMATIC    0  ///< libavcodec will select the mode itself
3038 #define FF_SUB_CHARENC_MODE_PRE_DECODER  1  ///< the AVPacket data needs to be recoded to UTF-8 before being fed to the decoder, requires iconv
3039 
3040     /**
3041      * Skip processing alpha if supported by codec.
3042      * Note that if the format uses pre-multiplied alpha (common with VP6,
3043      * and recommended due to better video quality/compression)
3044      * the image will look as if alpha-blended onto a black background.
3045      * However for formats that do not use pre-multiplied alpha
3046      * there might be serious artefacts (though e.g. libswscale currently
3047      * assumes pre-multiplied alpha anyway).
3048      * Code outside libavcodec should access this field using AVOptions
3049      *
3050      * - decoding: set by user
3051      * - encoding: unused
3052      */
3053     int skip_alpha;
3054 
3055     /**
3056      * Number of samples to skip after a discontinuity
3057      * - decoding: unused
3058      * - encoding: set by libavcodec
3059      */
3060     int seek_preroll;
3061 
3062 #if !FF_API_DEBUG_MV
3063     /**
3064      * debug motion vectors
3065      * Code outside libavcodec should access this field using AVOptions
3066      * - encoding: Set by user.
3067      * - decoding: Set by user.
3068      */
3069     int debug_mv;
3070 #define FF_DEBUG_VIS_MV_P_FOR  0x00000001 //visualize forward predicted MVs of P frames
3071 #define FF_DEBUG_VIS_MV_B_FOR  0x00000002 //visualize forward predicted MVs of B frames
3072 #define FF_DEBUG_VIS_MV_B_BACK 0x00000004 //visualize backward predicted MVs of B frames
3073 #endif
3074 
3075     /**
3076      * custom intra quantization matrix
3077      * Code outside libavcodec should access this field using av_codec_g/set_chroma_intra_matrix()
3078      * - encoding: Set by user, can be NULL.
3079      * - decoding: unused.
3080      */
3081     uint16_t *chroma_intra_matrix;
3082 } AVCodecContext;
3083 
3084 AVRational av_codec_get_pkt_timebase         (const AVCodecContext *avctx);
3085 void       av_codec_set_pkt_timebase         (AVCodecContext *avctx, AVRational val);
3086 
3087 const AVCodecDescriptor *av_codec_get_codec_descriptor(const AVCodecContext *avctx);
3088 void                     av_codec_set_codec_descriptor(AVCodecContext *avctx, const AVCodecDescriptor *desc);
3089 
3090 int  av_codec_get_lowres(const AVCodecContext *avctx);
3091 void av_codec_set_lowres(AVCodecContext *avctx, int val);
3092 
3093 int  av_codec_get_seek_preroll(const AVCodecContext *avctx);
3094 void av_codec_set_seek_preroll(AVCodecContext *avctx, int val);
3095 
3096 uint16_t *av_codec_get_chroma_intra_matrix(const AVCodecContext *avctx);
3097 void av_codec_set_chroma_intra_matrix(AVCodecContext *avctx, uint16_t *val);
3098 
3099 /**
3100  * AVProfile.
3101  */
3102 typedef struct AVProfile {
3103     int profile;
3104     const char *name; ///< short name for the profile
3105 } AVProfile;
3106 
3107 typedef struct AVCodecDefault AVCodecDefault;
3108 
3109 struct AVSubtitle;
3110 
3111 /**
3112  * AVCodec.
3113  */
3114 typedef struct AVCodec {
3115     /**
3116      * Name of the codec implementation.
3117      * The name is globally unique among encoders and among decoders (but an
3118      * encoder and a decoder can share the same name).
3119      * This is the primary way to find a codec from the user perspective.
3120      */
3121     const char *name;
3122     /**
3123      * Descriptive name for the codec, meant to be more human readable than name.
3124      * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
3125      */
3126     const char *long_name;
3127     enum AVMediaType type;
3128     enum AVCodecID id;
3129     /**
3130      * Codec capabilities.
3131      * see CODEC_CAP_*
3132      */
3133     int capabilities;
3134     const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0}
3135     const enum AVPixelFormat *pix_fmts;     ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1
3136     const int *supported_samplerates;       ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0
3137     const enum AVSampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1
3138     const uint64_t *channel_layouts;         ///< array of support channel layouts, or NULL if unknown. array is terminated by 0
3139 #if FF_API_LOWRES
3140     uint8_t max_lowres;                     ///< maximum value for lowres supported by the decoder, no direct access, use av_codec_get_max_lowres()
3141 #endif
3142     const AVClass *priv_class;              ///< AVClass for the private context
3143     const AVProfile *profiles;              ///< array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}
3144 
3145     /*****************************************************************
3146      * No fields below this line are part of the public API. They
3147      * may not be used outside of libavcodec and can be changed and
3148      * removed at will.
3149      * New public fields should be added right above.
3150      *****************************************************************
3151      */
3152     int priv_data_size;
3153     struct AVCodec *next;
3154     /**
3155      * @name Frame-level threading support functions
3156      * @{
3157      */
3158     /**
3159      * If defined, called on thread contexts when they are created.
3160      * If the codec allocates writable tables in init(), re-allocate them here.
3161      * priv_data will be set to a copy of the original.
3162      */
3163     int (*init_thread_copy)(AVCodecContext *);
3164     /**
3165      * Copy necessary context variables from a previous thread context to the current one.
3166      * If not defined, the next thread will start automatically; otherwise, the codec
3167      * must call ff_thread_finish_setup().
3168      *
3169      * dst and src will (rarely) point to the same context, in which case memcpy should be skipped.
3170      */
3171     int (*update_thread_context)(AVCodecContext *dst, const AVCodecContext *src);
3172     /** @} */
3173 
3174     /**
3175      * Private codec-specific defaults.
3176      */
3177     const AVCodecDefault *defaults;
3178 
3179     /**
3180      * Initialize codec static data, called from avcodec_register().
3181      */
3182     void (*init_static_data)(struct AVCodec *codec);
3183 
3184     int (*init)(AVCodecContext *);
3185     int (*encode_sub)(AVCodecContext *, uint8_t *buf, int buf_size,
3186                       const struct AVSubtitle *sub);
3187     /**
3188      * Encode data to an AVPacket.
3189      *
3190      * @param      avctx          codec context
3191      * @param      avpkt          output AVPacket (may contain a user-provided buffer)
3192      * @param[in]  frame          AVFrame containing the raw data to be encoded
3193      * @param[out] got_packet_ptr encoder sets to 0 or 1 to indicate that a
3194      *                            non-empty packet was returned in avpkt.
3195      * @return 0 on success, negative error code on failure
3196      */
3197     int (*encode2)(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame,
3198                    int *got_packet_ptr);
3199     int (*decode)(AVCodecContext *, void *outdata, int *outdata_size, AVPacket *avpkt);
3200     int (*close)(AVCodecContext *);
3201     /**
3202      * Flush buffers.
3203      * Will be called when seeking
3204      */
3205     void (*flush)(AVCodecContext *);
3206 } AVCodec;
3207 
3208 int av_codec_get_max_lowres(const AVCodec *codec);
3209 
3210 struct MpegEncContext;
3211 
3212 /**
3213  * AVHWAccel.
3214  */
3215 typedef struct AVHWAccel {
3216     /**
3217      * Name of the hardware accelerated codec.
3218      * The name is globally unique among encoders and among decoders (but an
3219      * encoder and a decoder can share the same name).
3220      */
3221     const char *name;
3222 
3223     /**
3224      * Type of codec implemented by the hardware accelerator.
3225      *
3226      * See AVMEDIA_TYPE_xxx
3227      */
3228     enum AVMediaType type;
3229 
3230     /**
3231      * Codec implemented by the hardware accelerator.
3232      *
3233      * See AV_CODEC_ID_xxx
3234      */
3235     enum AVCodecID id;
3236 
3237     /**
3238      * Supported pixel format.
3239      *
3240      * Only hardware accelerated formats are supported here.
3241      */
3242     enum AVPixelFormat pix_fmt;
3243 
3244     /**
3245      * Hardware accelerated codec capabilities.
3246      * see FF_HWACCEL_CODEC_CAP_*
3247      */
3248     int capabilities;
3249 
3250     /*****************************************************************
3251      * No fields below this line are part of the public API. They
3252      * may not be used outside of libavcodec and can be changed and
3253      * removed at will.
3254      * New public fields should be added right above.
3255      *****************************************************************
3256      */
3257     struct AVHWAccel *next;
3258 
3259     /**
3260      * Allocate a custom buffer
3261      */
3262     int (*alloc_frame)(AVCodecContext *avctx, AVFrame *frame);
3263 
3264     /**
3265      * Called at the beginning of each frame or field picture.
3266      *
3267      * Meaningful frame information (codec specific) is guaranteed to
3268      * be parsed at this point. This function is mandatory.
3269      *
3270      * Note that buf can be NULL along with buf_size set to 0.
3271      * Otherwise, this means the whole frame is available at this point.
3272      *
3273      * @param avctx the codec context
3274      * @param buf the frame data buffer base
3275      * @param buf_size the size of the frame in bytes
3276      * @return zero if successful, a negative value otherwise
3277      */
3278     int (*start_frame)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
3279 
3280     /**
3281      * Callback for each slice.
3282      *
3283      * Meaningful slice information (codec specific) is guaranteed to
3284      * be parsed at this point. This function is mandatory.
3285      * The only exception is XvMC, that works on MB level.
3286      *
3287      * @param avctx the codec context
3288      * @param buf the slice data buffer base
3289      * @param buf_size the size of the slice in bytes
3290      * @return zero if successful, a negative value otherwise
3291      */
3292     int (*decode_slice)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
3293 
3294     /**
3295      * Called at the end of each frame or field picture.
3296      *
3297      * The whole picture is parsed at this point and can now be sent
3298      * to the hardware accelerator. This function is mandatory.
3299      *
3300      * @param avctx the codec context
3301      * @return zero if successful, a negative value otherwise
3302      */
3303     int (*end_frame)(AVCodecContext *avctx);
3304 
3305     /**
3306      * Size of per-frame hardware accelerator private data.
3307      *
3308      * Private data is allocated with av_mallocz() before
3309      * AVCodecContext.get_buffer() and deallocated after
3310      * AVCodecContext.release_buffer().
3311      */
3312     int frame_priv_data_size;
3313 
3314     /**
3315      * Called for every Macroblock in a slice.
3316      *
3317      * XvMC uses it to replace the ff_mpv_decode_mb().
3318      * Instead of decoding to raw picture, MB parameters are
3319      * stored in an array provided by the video driver.
3320      *
3321      * @param s the mpeg context
3322      */
3323     void (*decode_mb)(struct MpegEncContext *s);
3324 
3325     /**
3326      * Initialize the hwaccel private data.
3327      *
3328      * This will be called from ff_get_format(), after hwaccel and
3329      * hwaccel_context are set and the hwaccel private data in AVCodecInternal
3330      * is allocated.
3331      */
3332     int (*init)(AVCodecContext *avctx);
3333 
3334     /**
3335      * Uninitialize the hwaccel private data.
3336      *
3337      * This will be called from get_format() or avcodec_close(), after hwaccel
3338      * and hwaccel_context are already uninitialized.
3339      */
3340     int (*uninit)(AVCodecContext *avctx);
3341 
3342     /**
3343      * Size of the private data to allocate in
3344      * AVCodecInternal.hwaccel_priv_data.
3345      */
3346     int priv_data_size;
3347 } AVHWAccel;
3348 
3349 /**
3350  * @defgroup lavc_picture AVPicture
3351  *
3352  * Functions for working with AVPicture
3353  * @{
3354  */
3355 
3356 /**
3357  * Picture data structure.
3358  *
3359  * Up to four components can be stored into it, the last component is
3360  * alpha.
3361  */
3362 typedef struct AVPicture {
3363     uint8_t *data[AV_NUM_DATA_POINTERS];    ///< pointers to the image data planes
3364     int linesize[AV_NUM_DATA_POINTERS];     ///< number of bytes per line
3365 } AVPicture;
3366 
3367 /**
3368  * @}
3369  */
3370 
3371 enum AVSubtitleType {
3372     SUBTITLE_NONE,
3373 
3374     SUBTITLE_BITMAP,                ///< A bitmap, pict will be set
3375 
3376     /**
3377      * Plain text, the text field must be set by the decoder and is
3378      * authoritative. ass and pict fields may contain approximations.
3379      */
3380     SUBTITLE_TEXT,
3381 
3382     /**
3383      * Formatted text, the ass field must be set by the decoder and is
3384      * authoritative. pict and text fields may contain approximations.
3385      */
3386     SUBTITLE_ASS,
3387 };
3388 
3389 #define AV_SUBTITLE_FLAG_FORCED 0x00000001
3390 
3391 typedef struct AVSubtitleRect {
3392     int x;         ///< top left corner  of pict, undefined when pict is not set
3393     int y;         ///< top left corner  of pict, undefined when pict is not set
3394     int w;         ///< width            of pict, undefined when pict is not set
3395     int h;         ///< height           of pict, undefined when pict is not set
3396     int nb_colors; ///< number of colors in pict, undefined when pict is not set
3397 
3398     /**
3399      * data+linesize for the bitmap of this subtitle.
3400      * can be set for text/ass as well once they where rendered
3401      */
3402     AVPicture pict;
3403     enum AVSubtitleType type;
3404 
3405     char *text;                     ///< 0 terminated plain UTF-8 text
3406 
3407     /**
3408      * 0 terminated ASS/SSA compatible event line.
3409      * The presentation of this is unaffected by the other values in this
3410      * struct.
3411      */
3412     char *ass;
3413 
3414     int flags;
3415 } AVSubtitleRect;
3416 
3417 typedef struct AVSubtitle {
3418     uint16_t format; /* 0 = graphics */
3419     uint32_t start_display_time; /* relative to packet pts, in ms */
3420     uint32_t end_display_time; /* relative to packet pts, in ms */
3421     unsigned num_rects;
3422     AVSubtitleRect **rects;
3423     int64_t pts;    ///< Same as packet pts, in AV_TIME_BASE
3424 } AVSubtitle;
3425 
3426 /**
3427  * If c is NULL, returns the first registered codec,
3428  * if c is non-NULL, returns the next registered codec after c,
3429  * or NULL if c is the last one.
3430  */
3431 AVCodec *av_codec_next(const AVCodec *c);
3432 
3433 /**
3434  * Return the LIBAVCODEC_VERSION_INT constant.
3435  */
3436 unsigned avcodec_version(void);
3437 
3438 /**
3439  * Return the libavcodec build-time configuration.
3440  */
3441 const char *avcodec_configuration(void);
3442 
3443 /**
3444  * Return the libavcodec license.
3445  */
3446 const char *avcodec_license(void);
3447 
3448 /**
3449  * Register the codec codec and initialize libavcodec.
3450  *
3451  * @warning either this function or avcodec_register_all() must be called
3452  * before any other libavcodec functions.
3453  *
3454  * @see avcodec_register_all()
3455  */
3456 void avcodec_register(AVCodec *codec);
3457 
3458 /**
3459  * Register all the codecs, parsers and bitstream filters which were enabled at
3460  * configuration time. If you do not call this function you can select exactly
3461  * which formats you want to support, by using the individual registration
3462  * functions.
3463  *
3464  * @see avcodec_register
3465  * @see av_register_codec_parser
3466  * @see av_register_bitstream_filter
3467  */
3468 void avcodec_register_all(void);
3469 
3470 /**
3471  * Allocate an AVCodecContext and set its fields to default values. The
3472  * resulting struct should be freed with avcodec_free_context().
3473  *
3474  * @param codec if non-NULL, allocate private data and initialize defaults
3475  *              for the given codec. It is illegal to then call avcodec_open2()
3476  *              with a different codec.
3477  *              If NULL, then the codec-specific defaults won't be initialized,
3478  *              which may result in suboptimal default settings (this is
3479  *              important mainly for encoders, e.g. libx264).
3480  *
3481  * @return An AVCodecContext filled with default values or NULL on failure.
3482  * @see avcodec_get_context_defaults
3483  */
3484 AVCodecContext *avcodec_alloc_context3(const AVCodec *codec);
3485 
3486 /**
3487  * Free the codec context and everything associated with it and write NULL to
3488  * the provided pointer.
3489  */
3490 void avcodec_free_context(AVCodecContext **avctx);
3491 
3492 /**
3493  * Set the fields of the given AVCodecContext to default values corresponding
3494  * to the given codec (defaults may be codec-dependent).
3495  *
3496  * Do not call this function if a non-NULL codec has been passed
3497  * to avcodec_alloc_context3() that allocated this AVCodecContext.
3498  * If codec is non-NULL, it is illegal to call avcodec_open2() with a
3499  * different codec on this AVCodecContext.
3500  */
3501 int avcodec_get_context_defaults3(AVCodecContext *s, const AVCodec *codec);
3502 
3503 /**
3504  * Get the AVClass for AVCodecContext. It can be used in combination with
3505  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
3506  *
3507  * @see av_opt_find().
3508  */
3509 const AVClass *avcodec_get_class(void);
3510 
3511 /**
3512  * Get the AVClass for AVFrame. It can be used in combination with
3513  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
3514  *
3515  * @see av_opt_find().
3516  */
3517 const AVClass *avcodec_get_frame_class(void);
3518 
3519 /**
3520  * Get the AVClass for AVSubtitleRect. It can be used in combination with
3521  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
3522  *
3523  * @see av_opt_find().
3524  */
3525 const AVClass *avcodec_get_subtitle_rect_class(void);
3526 
3527 /**
3528  * Copy the settings of the source AVCodecContext into the destination
3529  * AVCodecContext. The resulting destination codec context will be
3530  * unopened, i.e. you are required to call avcodec_open2() before you
3531  * can use this AVCodecContext to decode/encode video/audio data.
3532  *
3533  * @param dest target codec context, should be initialized with
3534  *             avcodec_alloc_context3(NULL), but otherwise uninitialized
3535  * @param src source codec context
3536  * @return AVERROR() on error (e.g. memory allocation error), 0 on success
3537  */
3538 int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src);
3539 
3540 #if FF_API_AVFRAME_LAVC
3541 /**
3542  * @deprecated use av_frame_alloc()
3543  */
3544 attribute_deprecated
3545 AVFrame *avcodec_alloc_frame(void);
3546 
3547 /**
3548  * Set the fields of the given AVFrame to default values.
3549  *
3550  * @param frame The AVFrame of which the fields should be set to default values.
3551  *
3552  * @deprecated use av_frame_unref()
3553  */
3554 attribute_deprecated
3555 void avcodec_get_frame_defaults(AVFrame *frame);
3556 
3557 /**
3558  * Free the frame and any dynamically allocated objects in it,
3559  * e.g. extended_data.
3560  *
3561  * @param frame frame to be freed. The pointer will be set to NULL.
3562  *
3563  * @warning this function does NOT free the data buffers themselves
3564  * (it does not know how, since they might have been allocated with
3565  *  a custom get_buffer()).
3566  *
3567  * @deprecated use av_frame_free()
3568  */
3569 attribute_deprecated
3570 void avcodec_free_frame(AVFrame **frame);
3571 #endif
3572 
3573 /**
3574  * Initialize the AVCodecContext to use the given AVCodec. Prior to using this
3575  * function the context has to be allocated with avcodec_alloc_context3().
3576  *
3577  * The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
3578  * avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
3579  * retrieving a codec.
3580  *
3581  * @warning This function is not thread safe!
3582  *
3583  * @code
3584  * avcodec_register_all();
3585  * av_dict_set(&opts, "b", "2.5M", 0);
3586  * codec = avcodec_find_decoder(AV_CODEC_ID_H264);
3587  * if (!codec)
3588  *     exit(1);
3589  *
3590  * context = avcodec_alloc_context3(codec);
3591  *
3592  * if (avcodec_open2(context, codec, opts) < 0)
3593  *     exit(1);
3594  * @endcode
3595  *
3596  * @param avctx The context to initialize.
3597  * @param codec The codec to open this context for. If a non-NULL codec has been
3598  *              previously passed to avcodec_alloc_context3() or
3599  *              avcodec_get_context_defaults3() for this context, then this
3600  *              parameter MUST be either NULL or equal to the previously passed
3601  *              codec.
3602  * @param options A dictionary filled with AVCodecContext and codec-private options.
3603  *                On return this object will be filled with options that were not found.
3604  *
3605  * @return zero on success, a negative value on error
3606  * @see avcodec_alloc_context3(), avcodec_find_decoder(), avcodec_find_encoder(),
3607  *      av_dict_set(), av_opt_find().
3608  */
3609 int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);
3610 
3611 /**
3612  * Close a given AVCodecContext and free all the data associated with it
3613  * (but not the AVCodecContext itself).
3614  *
3615  * Calling this function on an AVCodecContext that hasn't been opened will free
3616  * the codec-specific data allocated in avcodec_alloc_context3() /
3617  * avcodec_get_context_defaults3() with a non-NULL codec. Subsequent calls will
3618  * do nothing.
3619  */
3620 int avcodec_close(AVCodecContext *avctx);
3621 
3622 /**
3623  * Free all allocated data in the given subtitle struct.
3624  *
3625  * @param sub AVSubtitle to free.
3626  */
3627 void avsubtitle_free(AVSubtitle *sub);
3628 
3629 /**
3630  * @}
3631  */
3632 
3633 /**
3634  * @addtogroup lavc_packet
3635  * @{
3636  */
3637 
3638 #if FF_API_DESTRUCT_PACKET
3639 /**
3640  * Default packet destructor.
3641  * @deprecated use the AVBuffer API instead
3642  */
3643 attribute_deprecated
3644 void av_destruct_packet(AVPacket *pkt);
3645 #endif
3646 
3647 /**
3648  * Initialize optional fields of a packet with default values.
3649  *
3650  * Note, this does not touch the data and size members, which have to be
3651  * initialized separately.
3652  *
3653  * @param pkt packet
3654  */
3655 void av_init_packet(AVPacket *pkt);
3656 
3657 /**
3658  * Allocate the payload of a packet and initialize its fields with
3659  * default values.
3660  *
3661  * @param pkt packet
3662  * @param size wanted payload size
3663  * @return 0 if OK, AVERROR_xxx otherwise
3664  */
3665 int av_new_packet(AVPacket *pkt, int size);
3666 
3667 /**
3668  * Reduce packet size, correctly zeroing padding
3669  *
3670  * @param pkt packet
3671  * @param size new size
3672  */
3673 void av_shrink_packet(AVPacket *pkt, int size);
3674 
3675 /**
3676  * Increase packet size, correctly zeroing padding
3677  *
3678  * @param pkt packet
3679  * @param grow_by number of bytes by which to increase the size of the packet
3680  */
3681 int av_grow_packet(AVPacket *pkt, int grow_by);
3682 
3683 /**
3684  * Initialize a reference-counted packet from av_malloc()ed data.
3685  *
3686  * @param pkt packet to be initialized. This function will set the data, size,
3687  *        buf and destruct fields, all others are left untouched.
3688  * @param data Data allocated by av_malloc() to be used as packet data. If this
3689  *        function returns successfully, the data is owned by the underlying AVBuffer.
3690  *        The caller may not access the data through other means.
3691  * @param size size of data in bytes, without the padding. I.e. the full buffer
3692  *        size is assumed to be size + FF_INPUT_BUFFER_PADDING_SIZE.
3693  *
3694  * @return 0 on success, a negative AVERROR on error
3695  */
3696 int av_packet_from_data(AVPacket *pkt, uint8_t *data, int size);
3697 
3698 /**
3699  * @warning This is a hack - the packet memory allocation stuff is broken. The
3700  * packet is allocated if it was not really allocated.
3701  */
3702 int av_dup_packet(AVPacket *pkt);
3703 
3704 /**
3705  * Copy packet, including contents
3706  *
3707  * @return 0 on success, negative AVERROR on fail
3708  */
3709 int av_copy_packet(AVPacket *dst, const AVPacket *src);
3710 
3711 /**
3712  * Copy packet side data
3713  *
3714  * @return 0 on success, negative AVERROR on fail
3715  */
3716 int av_copy_packet_side_data(AVPacket *dst, const AVPacket *src);
3717 
3718 /**
3719  * Free a packet.
3720  *
3721  * @param pkt packet to free
3722  */
3723 void av_free_packet(AVPacket *pkt);
3724 
3725 /**
3726  * Allocate new information of a packet.
3727  *
3728  * @param pkt packet
3729  * @param type side information type
3730  * @param size side information size
3731  * @return pointer to fresh allocated data or NULL otherwise
3732  */
3733 uint8_t* av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
3734                                  int size);
3735 
3736 /**
3737  * Shrink the already allocated side data buffer
3738  *
3739  * @param pkt packet
3740  * @param type side information type
3741  * @param size new side information size
3742  * @return 0 on success, < 0 on failure
3743  */
3744 int av_packet_shrink_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
3745                                int size);
3746 
3747 /**
3748  * Get side information from packet.
3749  *
3750  * @param pkt packet
3751  * @param type desired side information type
3752  * @param size pointer for side information size to store (optional)
3753  * @return pointer to data if present or NULL otherwise
3754  */
3755 uint8_t* av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
3756                                  int *size);
3757 
3758 int av_packet_merge_side_data(AVPacket *pkt);
3759 
3760 int av_packet_split_side_data(AVPacket *pkt);
3761 
3762 /**
3763  * Pack a dictionary for use in side_data.
3764  *
3765  * @param dict The dictionary to pack.
3766  * @param size pointer to store the size of the returned data
3767  * @return pointer to data if successful, NULL otherwise
3768  */
3769 uint8_t *av_packet_pack_dictionary(AVDictionary *dict, int *size);
3770 /**
3771  * Unpack a dictionary from side_data.
3772  *
3773  * @param data data from side_data
3774  * @param size size of the data
3775  * @param dict the metadata storage dictionary
3776  * @return 0 on success, < 0 on failure
3777  */
3778 int av_packet_unpack_dictionary(const uint8_t *data, int size, AVDictionary **dict);
3779 
3780 
3781 /**
3782  * Convenience function to free all the side data stored.
3783  * All the other fields stay untouched.
3784  *
3785  * @param pkt packet
3786  */
3787 void av_packet_free_side_data(AVPacket *pkt);
3788 
3789 /**
3790  * Setup a new reference to the data described by a given packet
3791  *
3792  * If src is reference-counted, setup dst as a new reference to the
3793  * buffer in src. Otherwise allocate a new buffer in dst and copy the
3794  * data from src into it.
3795  *
3796  * All the other fields are copied from src.
3797  *
3798  * @see av_packet_unref
3799  *
3800  * @param dst Destination packet
3801  * @param src Source packet
3802  *
3803  * @return 0 on success, a negative AVERROR on error.
3804  */
3805 int av_packet_ref(AVPacket *dst, const AVPacket *src);
3806 
3807 /**
3808  * Wipe the packet.
3809  *
3810  * Unreference the buffer referenced by the packet and reset the
3811  * remaining packet fields to their default values.
3812  *
3813  * @param pkt The packet to be unreferenced.
3814  */
3815 void av_packet_unref(AVPacket *pkt);
3816 
3817 /**
3818  * Move every field in src to dst and reset src.
3819  *
3820  * @see av_packet_unref
3821  *
3822  * @param src Source packet, will be reset
3823  * @param dst Destination packet
3824  */
3825 void av_packet_move_ref(AVPacket *dst, AVPacket *src);
3826 
3827 /**
3828  * Copy only "properties" fields from src to dst.
3829  *
3830  * Properties for the purpose of this function are all the fields
3831  * beside those related to the packet data (buf, data, size)
3832  *
3833  * @param dst Destination packet
3834  * @param src Source packet
3835  *
3836  * @return 0 on success AVERROR on failure.
3837  *
3838  */
3839 int av_packet_copy_props(AVPacket *dst, const AVPacket *src);
3840 
3841 /**
3842  * Convert valid timing fields (timestamps / durations) in a packet from one
3843  * timebase to another. Timestamps with unknown values (AV_NOPTS_VALUE) will be
3844  * ignored.
3845  *
3846  * @param pkt packet on which the conversion will be performed
3847  * @param tb_src source timebase, in which the timing fields in pkt are
3848  *               expressed
3849  * @param tb_dst destination timebase, to which the timing fields will be
3850  *               converted
3851  */
3852 void av_packet_rescale_ts(AVPacket *pkt, AVRational tb_src, AVRational tb_dst);
3853 
3854 /**
3855  * @}
3856  */
3857 
3858 /**
3859  * @addtogroup lavc_decoding
3860  * @{
3861  */
3862 
3863 /**
3864  * Find a registered decoder with a matching codec ID.
3865  *
3866  * @param id AVCodecID of the requested decoder
3867  * @return A decoder if one was found, NULL otherwise.
3868  */
3869 AVCodec *avcodec_find_decoder(enum AVCodecID id);
3870 
3871 /**
3872  * Find a registered decoder with the specified name.
3873  *
3874  * @param name name of the requested decoder
3875  * @return A decoder if one was found, NULL otherwise.
3876  */
3877 AVCodec *avcodec_find_decoder_by_name(const char *name);
3878 
3879 #if FF_API_GET_BUFFER
3880 attribute_deprecated int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic);
3881 attribute_deprecated void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic);
3882 attribute_deprecated int avcodec_default_reget_buffer(AVCodecContext *s, AVFrame *pic);
3883 #endif
3884 
3885 /**
3886  * The default callback for AVCodecContext.get_buffer2(). It is made public so
3887  * it can be called by custom get_buffer2() implementations for decoders without
3888  * CODEC_CAP_DR1 set.
3889  */
3890 int avcodec_default_get_buffer2(AVCodecContext *s, AVFrame *frame, int flags);
3891 
3892 #if FF_API_EMU_EDGE
3893 /**
3894  * Return the amount of padding in pixels which the get_buffer callback must
3895  * provide around the edge of the image for codecs which do not have the
3896  * CODEC_FLAG_EMU_EDGE flag.
3897  *
3898  * @return Required padding in pixels.
3899  *
3900  * @deprecated CODEC_FLAG_EMU_EDGE is deprecated, so this function is no longer
3901  * needed
3902  */
3903 attribute_deprecated
3904 unsigned avcodec_get_edge_width(void);
3905 #endif
3906 
3907 /**
3908  * Modify width and height values so that they will result in a memory
3909  * buffer that is acceptable for the codec if you do not use any horizontal
3910  * padding.
3911  *
3912  * May only be used if a codec with CODEC_CAP_DR1 has been opened.
3913  */
3914 void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height);
3915 
3916 /**
3917  * Modify width and height values so that they will result in a memory
3918  * buffer that is acceptable for the codec if you also ensure that all
3919  * line sizes are a multiple of the respective linesize_align[i].
3920  *
3921  * May only be used if a codec with CODEC_CAP_DR1 has been opened.
3922  */
3923 void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
3924                                int linesize_align[AV_NUM_DATA_POINTERS]);
3925 
3926 /**
3927  * Converts AVChromaLocation to swscale x/y chroma position.
3928  *
3929  * The positions represent the chroma (0,0) position in a coordinates system
3930  * with luma (0,0) representing the origin and luma(1,1) representing 256,256
3931  *
3932  * @param xpos  horizontal chroma sample position
3933  * @param ypos  vertical   chroma sample position
3934  */
3935 int avcodec_enum_to_chroma_pos(int *xpos, int *ypos, enum AVChromaLocation pos);
3936 
3937 /**
3938  * Converts swscale x/y chroma position to AVChromaLocation.
3939  *
3940  * The positions represent the chroma (0,0) position in a coordinates system
3941  * with luma (0,0) representing the origin and luma(1,1) representing 256,256
3942  *
3943  * @param xpos  horizontal chroma sample position
3944  * @param ypos  vertical   chroma sample position
3945  */
3946 enum AVChromaLocation avcodec_chroma_pos_to_enum(int xpos, int ypos);
3947 
3948 #if FF_API_OLD_DECODE_AUDIO
3949 /**
3950  * Wrapper function which calls avcodec_decode_audio4.
3951  *
3952  * @deprecated Use avcodec_decode_audio4 instead.
3953  *
3954  * Decode the audio frame of size avpkt->size from avpkt->data into samples.
3955  * Some decoders may support multiple frames in a single AVPacket, such
3956  * decoders would then just decode the first frame. In this case,
3957  * avcodec_decode_audio3 has to be called again with an AVPacket that contains
3958  * the remaining data in order to decode the second frame etc.
3959  * If no frame
3960  * could be outputted, frame_size_ptr is zero. Otherwise, it is the
3961  * decompressed frame size in bytes.
3962  *
3963  * @warning You must set frame_size_ptr to the allocated size of the
3964  * output buffer before calling avcodec_decode_audio3().
3965  *
3966  * @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
3967  * the actual read bytes because some optimized bitstream readers read 32 or 64
3968  * bits at once and could read over the end.
3969  *
3970  * @warning The end of the input buffer avpkt->data should be set to 0 to ensure that
3971  * no overreading happens for damaged MPEG streams.
3972  *
3973  * @warning You must not provide a custom get_buffer() when using
3974  * avcodec_decode_audio3().  Doing so will override it with
3975  * avcodec_default_get_buffer.  Use avcodec_decode_audio4() instead,
3976  * which does allow the application to provide a custom get_buffer().
3977  *
3978  * @note You might have to align the input buffer avpkt->data and output buffer
3979  * samples. The alignment requirements depend on the CPU: On some CPUs it isn't
3980  * necessary at all, on others it won't work at all if not aligned and on others
3981  * it will work but it will have an impact on performance.
3982  *
3983  * In practice, avpkt->data should have 4 byte alignment at minimum and
3984  * samples should be 16 byte aligned unless the CPU doesn't need it
3985  * (AltiVec and SSE do).
3986  *
3987  * @note Codecs which have the CODEC_CAP_DELAY capability set have a delay
3988  * between input and output, these need to be fed with avpkt->data=NULL,
3989  * avpkt->size=0 at the end to return the remaining frames.
3990  *
3991  * @param avctx the codec context
3992  * @param[out] samples the output buffer, sample type in avctx->sample_fmt
3993  *                     If the sample format is planar, each channel plane will
3994  *                     be the same size, with no padding between channels.
3995  * @param[in,out] frame_size_ptr the output buffer size in bytes
3996  * @param[in] avpkt The input AVPacket containing the input buffer.
3997  *            You can create such packet with av_init_packet() and by then setting
3998  *            data and size, some decoders might in addition need other fields.
3999  *            All decoders are designed to use the least fields possible though.
4000  * @return On error a negative value is returned, otherwise the number of bytes
4001  * used or zero if no frame data was decompressed (used) from the input AVPacket.
4002  */
4003 attribute_deprecated int avcodec_decode_audio3(AVCodecContext *avctx, int16_t *samples,
4004                          int *frame_size_ptr,
4005                          AVPacket *avpkt);
4006 #endif
4007 
4008 /**
4009  * Decode the audio frame of size avpkt->size from avpkt->data into frame.
4010  *
4011  * Some decoders may support multiple frames in a single AVPacket. Such
4012  * decoders would then just decode the first frame and the return value would be
4013  * less than the packet size. In this case, avcodec_decode_audio4 has to be
4014  * called again with an AVPacket containing the remaining data in order to
4015  * decode the second frame, etc...  Even if no frames are returned, the packet
4016  * needs to be fed to the decoder with remaining data until it is completely
4017  * consumed or an error occurs.
4018  *
4019  * Some decoders (those marked with CODEC_CAP_DELAY) have a delay between input
4020  * and output. This means that for some packets they will not immediately
4021  * produce decoded output and need to be flushed at the end of decoding to get
4022  * all the decoded data. Flushing is done by calling this function with packets
4023  * with avpkt->data set to NULL and avpkt->size set to 0 until it stops
4024  * returning samples. It is safe to flush even those decoders that are not
4025  * marked with CODEC_CAP_DELAY, then no samples will be returned.
4026  *
4027  * @warning The input buffer, avpkt->data must be FF_INPUT_BUFFER_PADDING_SIZE
4028  *          larger than the actual read bytes because some optimized bitstream
4029  *          readers read 32 or 64 bits at once and could read over the end.
4030  *
4031  * @param      avctx the codec context
4032  * @param[out] frame The AVFrame in which to store decoded audio samples.
4033  *                   The decoder will allocate a buffer for the decoded frame by
4034  *                   calling the AVCodecContext.get_buffer2() callback.
4035  *                   When AVCodecContext.refcounted_frames is set to 1, the frame is
4036  *                   reference counted and the returned reference belongs to the
4037  *                   caller. The caller must release the frame using av_frame_unref()
4038  *                   when the frame is no longer needed. The caller may safely write
4039  *                   to the frame if av_frame_is_writable() returns 1.
4040  *                   When AVCodecContext.refcounted_frames is set to 0, the returned
4041  *                   reference belongs to the decoder and is valid only until the
4042  *                   next call to this function or until closing or flushing the
4043  *                   decoder. The caller may not write to it.
4044  * @param[out] got_frame_ptr Zero if no frame could be decoded, otherwise it is
4045  *                           non-zero. Note that this field being set to zero
4046  *                           does not mean that an error has occurred. For
4047  *                           decoders with CODEC_CAP_DELAY set, no given decode
4048  *                           call is guaranteed to produce a frame.
4049  * @param[in]  avpkt The input AVPacket containing the input buffer.
4050  *                   At least avpkt->data and avpkt->size should be set. Some
4051  *                   decoders might also require additional fields to be set.
4052  * @return A negative error code is returned if an error occurred during
4053  *         decoding, otherwise the number of bytes consumed from the input
4054  *         AVPacket is returned.
4055  */
4056 int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame *frame,
4057                           int *got_frame_ptr, const AVPacket *avpkt);
4058 
4059 /**
4060  * Decode the video frame of size avpkt->size from avpkt->data into picture.
4061  * Some decoders may support multiple frames in a single AVPacket, such
4062  * decoders would then just decode the first frame.
4063  *
4064  * @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
4065  * the actual read bytes because some optimized bitstream readers read 32 or 64
4066  * bits at once and could read over the end.
4067  *
4068  * @warning The end of the input buffer buf should be set to 0 to ensure that
4069  * no overreading happens for damaged MPEG streams.
4070  *
4071  * @note Codecs which have the CODEC_CAP_DELAY capability set have a delay
4072  * between input and output, these need to be fed with avpkt->data=NULL,
4073  * avpkt->size=0 at the end to return the remaining frames.
4074  *
4075  * @param avctx the codec context
4076  * @param[out] picture The AVFrame in which the decoded video frame will be stored.
4077  *             Use av_frame_alloc() to get an AVFrame. The codec will
4078  *             allocate memory for the actual bitmap by calling the
4079  *             AVCodecContext.get_buffer2() callback.
4080  *             When AVCodecContext.refcounted_frames is set to 1, the frame is
4081  *             reference counted and the returned reference belongs to the
4082  *             caller. The caller must release the frame using av_frame_unref()
4083  *             when the frame is no longer needed. The caller may safely write
4084  *             to the frame if av_frame_is_writable() returns 1.
4085  *             When AVCodecContext.refcounted_frames is set to 0, the returned
4086  *             reference belongs to the decoder and is valid only until the
4087  *             next call to this function or until closing or flushing the
4088  *             decoder. The caller may not write to it.
4089  *
4090  * @param[in] avpkt The input AVPacket containing the input buffer.
4091  *            You can create such packet with av_init_packet() and by then setting
4092  *            data and size, some decoders might in addition need other fields like
4093  *            flags&AV_PKT_FLAG_KEY. All decoders are designed to use the least
4094  *            fields possible.
4095  * @param[in,out] got_picture_ptr Zero if no frame could be decompressed, otherwise, it is nonzero.
4096  * @return On error a negative value is returned, otherwise the number of bytes
4097  * used or zero if no frame could be decompressed.
4098  */
4099 int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
4100                          int *got_picture_ptr,
4101                          const AVPacket *avpkt);
4102 
4103 /**
4104  * Decode a subtitle message.
4105  * Return a negative value on error, otherwise return the number of bytes used.
4106  * If no subtitle could be decompressed, got_sub_ptr is zero.
4107  * Otherwise, the subtitle is stored in *sub.
4108  * Note that CODEC_CAP_DR1 is not available for subtitle codecs. This is for
4109  * simplicity, because the performance difference is expect to be negligible
4110  * and reusing a get_buffer written for video codecs would probably perform badly
4111  * due to a potentially very different allocation pattern.
4112  *
4113  * Some decoders (those marked with CODEC_CAP_DELAY) have a delay between input
4114  * and output. This means that for some packets they will not immediately
4115  * produce decoded output and need to be flushed at the end of decoding to get
4116  * all the decoded data. Flushing is done by calling this function with packets
4117  * with avpkt->data set to NULL and avpkt->size set to 0 until it stops
4118  * returning subtitles. It is safe to flush even those decoders that are not
4119  * marked with CODEC_CAP_DELAY, then no subtitles will be returned.
4120  *
4121  * @param avctx the codec context
4122  * @param[out] sub The Preallocated AVSubtitle in which the decoded subtitle will be stored,
4123  *                 must be freed with avsubtitle_free if *got_sub_ptr is set.
4124  * @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
4125  * @param[in] avpkt The input AVPacket containing the input buffer.
4126  */
4127 int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
4128                             int *got_sub_ptr,
4129                             AVPacket *avpkt);
4130 
4131 /**
4132  * @defgroup lavc_parsing Frame parsing
4133  * @{
4134  */
4135 
4136 enum AVPictureStructure {
4137     AV_PICTURE_STRUCTURE_UNKNOWN,      //< unknown
4138     AV_PICTURE_STRUCTURE_TOP_FIELD,    //< coded as top field
4139     AV_PICTURE_STRUCTURE_BOTTOM_FIELD, //< coded as bottom field
4140     AV_PICTURE_STRUCTURE_FRAME,        //< coded as frame
4141 };
4142 
4143 typedef struct AVCodecParserContext {
4144     void *priv_data;
4145     struct AVCodecParser *parser;
4146     int64_t frame_offset; /* offset of the current frame */
4147     int64_t cur_offset; /* current offset
4148                            (incremented by each av_parser_parse()) */
4149     int64_t next_frame_offset; /* offset of the next frame */
4150     /* video info */
4151     int pict_type; /* XXX: Put it back in AVCodecContext. */
4152     /**
4153      * This field is used for proper frame duration computation in lavf.
4154      * It signals, how much longer the frame duration of the current frame
4155      * is compared to normal frame duration.
4156      *
4157      * frame_duration = (1 + repeat_pict) * time_base
4158      *
4159      * It is used by codecs like H.264 to display telecined material.
4160      */
4161     int repeat_pict; /* XXX: Put it back in AVCodecContext. */
4162     int64_t pts;     /* pts of the current frame */
4163     int64_t dts;     /* dts of the current frame */
4164 
4165     /* private data */
4166     int64_t last_pts;
4167     int64_t last_dts;
4168     int fetch_timestamp;
4169 
4170 #define AV_PARSER_PTS_NB 4
4171     int cur_frame_start_index;
4172     int64_t cur_frame_offset[AV_PARSER_PTS_NB];
4173     int64_t cur_frame_pts[AV_PARSER_PTS_NB];
4174     int64_t cur_frame_dts[AV_PARSER_PTS_NB];
4175 
4176     int flags;
4177 #define PARSER_FLAG_COMPLETE_FRAMES           0x0001
4178 #define PARSER_FLAG_ONCE                      0x0002
4179 /// Set if the parser has a valid file offset
4180 #define PARSER_FLAG_FETCHED_OFFSET            0x0004
4181 #define PARSER_FLAG_USE_CODEC_TS              0x1000
4182 
4183     int64_t offset;      ///< byte offset from starting packet start
4184     int64_t cur_frame_end[AV_PARSER_PTS_NB];
4185 
4186     /**
4187      * Set by parser to 1 for key frames and 0 for non-key frames.
4188      * It is initialized to -1, so if the parser doesn't set this flag,
4189      * old-style fallback using AV_PICTURE_TYPE_I picture type as key frames
4190      * will be used.
4191      */
4192     int key_frame;
4193 
4194     /**
4195      * Time difference in stream time base units from the pts of this
4196      * packet to the point at which the output from the decoder has converged
4197      * independent from the availability of previous frames. That is, the
4198      * frames are virtually identical no matter if decoding started from
4199      * the very first frame or from this keyframe.
4200      * Is AV_NOPTS_VALUE if unknown.
4201      * This field is not the display duration of the current frame.
4202      * This field has no meaning if the packet does not have AV_PKT_FLAG_KEY
4203      * set.
4204      *
4205      * The purpose of this field is to allow seeking in streams that have no
4206      * keyframes in the conventional sense. It corresponds to the
4207      * recovery point SEI in H.264 and match_time_delta in NUT. It is also
4208      * essential for some types of subtitle streams to ensure that all
4209      * subtitles are correctly displayed after seeking.
4210      */
4211     int64_t convergence_duration;
4212 
4213     // Timestamp generation support:
4214     /**
4215      * Synchronization point for start of timestamp generation.
4216      *
4217      * Set to >0 for sync point, 0 for no sync point and <0 for undefined
4218      * (default).
4219      *
4220      * For example, this corresponds to presence of H.264 buffering period
4221      * SEI message.
4222      */
4223     int dts_sync_point;
4224 
4225     /**
4226      * Offset of the current timestamp against last timestamp sync point in
4227      * units of AVCodecContext.time_base.
4228      *
4229      * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
4230      * contain a valid timestamp offset.
4231      *
4232      * Note that the timestamp of sync point has usually a nonzero
4233      * dts_ref_dts_delta, which refers to the previous sync point. Offset of
4234      * the next frame after timestamp sync point will be usually 1.
4235      *
4236      * For example, this corresponds to H.264 cpb_removal_delay.
4237      */
4238     int dts_ref_dts_delta;
4239 
4240     /**
4241      * Presentation delay of current frame in units of AVCodecContext.time_base.
4242      *
4243      * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
4244      * contain valid non-negative timestamp delta (presentation time of a frame
4245      * must not lie in the past).
4246      *
4247      * This delay represents the difference between decoding and presentation
4248      * time of the frame.
4249      *
4250      * For example, this corresponds to H.264 dpb_output_delay.
4251      */
4252     int pts_dts_delta;
4253 
4254     /**
4255      * Position of the packet in file.
4256      *
4257      * Analogous to cur_frame_pts/dts
4258      */
4259     int64_t cur_frame_pos[AV_PARSER_PTS_NB];
4260 
4261     /**
4262      * Byte position of currently parsed frame in stream.
4263      */
4264     int64_t pos;
4265 
4266     /**
4267      * Previous frame byte position.
4268      */
4269     int64_t last_pos;
4270 
4271     /**
4272      * Duration of the current frame.
4273      * For audio, this is in units of 1 / AVCodecContext.sample_rate.
4274      * For all other types, this is in units of AVCodecContext.time_base.
4275      */
4276     int duration;
4277 
4278     enum AVFieldOrder field_order;
4279 
4280     /**
4281      * Indicate whether a picture is coded as a frame, top field or bottom field.
4282      *
4283      * For example, H.264 field_pic_flag equal to 0 corresponds to
4284      * AV_PICTURE_STRUCTURE_FRAME. An H.264 picture with field_pic_flag
4285      * equal to 1 and bottom_field_flag equal to 0 corresponds to
4286      * AV_PICTURE_STRUCTURE_TOP_FIELD.
4287      */
4288     enum AVPictureStructure picture_structure;
4289 
4290     /**
4291      * Picture number incremented in presentation or output order.
4292      * This field may be reinitialized at the first picture of a new sequence.
4293      *
4294      * For example, this corresponds to H.264 PicOrderCnt.
4295      */
4296     int output_picture_number;
4297 } AVCodecParserContext;
4298 
4299 typedef struct AVCodecParser {
4300     int codec_ids[5]; /* several codec IDs are permitted */
4301     int priv_data_size;
4302     int (*parser_init)(AVCodecParserContext *s);
4303     int (*parser_parse)(AVCodecParserContext *s,
4304                         AVCodecContext *avctx,
4305                         const uint8_t **poutbuf, int *poutbuf_size,
4306                         const uint8_t *buf, int buf_size);
4307     void (*parser_close)(AVCodecParserContext *s);
4308     int (*split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
4309     struct AVCodecParser *next;
4310 } AVCodecParser;
4311 
4312 AVCodecParser *av_parser_next(const AVCodecParser *c);
4313 
4314 void av_register_codec_parser(AVCodecParser *parser);
4315 AVCodecParserContext *av_parser_init(int codec_id);
4316 
4317 /**
4318  * Parse a packet.
4319  *
4320  * @param s             parser context.
4321  * @param avctx         codec context.
4322  * @param poutbuf       set to pointer to parsed buffer or NULL if not yet finished.
4323  * @param poutbuf_size  set to size of parsed buffer or zero if not yet finished.
4324  * @param buf           input buffer.
4325  * @param buf_size      input length, to signal EOF, this should be 0 (so that the last frame can be output).
4326  * @param pts           input presentation timestamp.
4327  * @param dts           input decoding timestamp.
4328  * @param pos           input byte position in stream.
4329  * @return the number of bytes of the input bitstream used.
4330  *
4331  * Example:
4332  * @code
4333  *   while(in_len){
4334  *       len = av_parser_parse2(myparser, AVCodecContext, &data, &size,
4335  *                                        in_data, in_len,
4336  *                                        pts, dts, pos);
4337  *       in_data += len;
4338  *       in_len  -= len;
4339  *
4340  *       if(size)
4341  *          decode_frame(data, size);
4342  *   }
4343  * @endcode
4344  */
4345 int av_parser_parse2(AVCodecParserContext *s,
4346                      AVCodecContext *avctx,
4347                      uint8_t **poutbuf, int *poutbuf_size,
4348                      const uint8_t *buf, int buf_size,
4349                      int64_t pts, int64_t dts,
4350                      int64_t pos);
4351 
4352 /**
4353  * @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
4354  * @deprecated use AVBitStreamFilter
4355  */
4356 int av_parser_change(AVCodecParserContext *s,
4357                      AVCodecContext *avctx,
4358                      uint8_t **poutbuf, int *poutbuf_size,
4359                      const uint8_t *buf, int buf_size, int keyframe);
4360 void av_parser_close(AVCodecParserContext *s);
4361 
4362 /**
4363  * @}
4364  * @}
4365  */
4366 
4367 /**
4368  * @addtogroup lavc_encoding
4369  * @{
4370  */
4371 
4372 /**
4373  * Find a registered encoder with a matching codec ID.
4374  *
4375  * @param id AVCodecID of the requested encoder
4376  * @return An encoder if one was found, NULL otherwise.
4377  */
4378 AVCodec *avcodec_find_encoder(enum AVCodecID id);
4379 
4380 /**
4381  * Find a registered encoder with the specified name.
4382  *
4383  * @param name name of the requested encoder
4384  * @return An encoder if one was found, NULL otherwise.
4385  */
4386 AVCodec *avcodec_find_encoder_by_name(const char *name);
4387 
4388 #if FF_API_OLD_ENCODE_AUDIO
4389 /**
4390  * Encode an audio frame from samples into buf.
4391  *
4392  * @deprecated Use avcodec_encode_audio2 instead.
4393  *
4394  * @note The output buffer should be at least FF_MIN_BUFFER_SIZE bytes large.
4395  * However, for codecs with avctx->frame_size equal to 0 (e.g. PCM) the user
4396  * will know how much space is needed because it depends on the value passed
4397  * in buf_size as described below. In that case a lower value can be used.
4398  *
4399  * @param avctx the codec context
4400  * @param[out] buf the output buffer
4401  * @param[in] buf_size the output buffer size
4402  * @param[in] samples the input buffer containing the samples
4403  * The number of samples read from this buffer is frame_size*channels,
4404  * both of which are defined in avctx.
4405  * For codecs which have avctx->frame_size equal to 0 (e.g. PCM) the number of
4406  * samples read from samples is equal to:
4407  * buf_size * 8 / (avctx->channels * av_get_bits_per_sample(avctx->codec_id))
4408  * This also implies that av_get_bits_per_sample() must not return 0 for these
4409  * codecs.
4410  * @return On error a negative value is returned, on success zero or the number
4411  * of bytes used to encode the data read from the input buffer.
4412  */
4413 int attribute_deprecated avcodec_encode_audio(AVCodecContext *avctx,
4414                                               uint8_t *buf, int buf_size,
4415                                               const short *samples);
4416 #endif
4417 
4418 /**
4419  * Encode a frame of audio.
4420  *
4421  * Takes input samples from frame and writes the next output packet, if
4422  * available, to avpkt. The output packet does not necessarily contain data for
4423  * the most recent frame, as encoders can delay, split, and combine input frames
4424  * internally as needed.
4425  *
4426  * @param avctx     codec context
4427  * @param avpkt     output AVPacket.
4428  *                  The user can supply an output buffer by setting
4429  *                  avpkt->data and avpkt->size prior to calling the
4430  *                  function, but if the size of the user-provided data is not
4431  *                  large enough, encoding will fail. If avpkt->data and
4432  *                  avpkt->size are set, avpkt->destruct must also be set. All
4433  *                  other AVPacket fields will be reset by the encoder using
4434  *                  av_init_packet(). If avpkt->data is NULL, the encoder will
4435  *                  allocate it. The encoder will set avpkt->size to the size
4436  *                  of the output packet.
4437  *
4438  *                  If this function fails or produces no output, avpkt will be
4439  *                  freed using av_free_packet() (i.e. avpkt->destruct will be
4440  *                  called to free the user supplied buffer).
4441  * @param[in] frame AVFrame containing the raw audio data to be encoded.
4442  *                  May be NULL when flushing an encoder that has the
4443  *                  CODEC_CAP_DELAY capability set.
4444  *                  If CODEC_CAP_VARIABLE_FRAME_SIZE is set, then each frame
4445  *                  can have any number of samples.
4446  *                  If it is not set, frame->nb_samples must be equal to
4447  *                  avctx->frame_size for all frames except the last.
4448  *                  The final frame may be smaller than avctx->frame_size.
4449  * @param[out] got_packet_ptr This field is set to 1 by libavcodec if the
4450  *                            output packet is non-empty, and to 0 if it is
4451  *                            empty. If the function returns an error, the
4452  *                            packet can be assumed to be invalid, and the
4453  *                            value of got_packet_ptr is undefined and should
4454  *                            not be used.
4455  * @return          0 on success, negative error code on failure
4456  */
4457 int avcodec_encode_audio2(AVCodecContext *avctx, AVPacket *avpkt,
4458                           const AVFrame *frame, int *got_packet_ptr);
4459 
4460 #if FF_API_OLD_ENCODE_VIDEO
4461 /**
4462  * @deprecated use avcodec_encode_video2() instead.
4463  *
4464  * Encode a video frame from pict into buf.
4465  * The input picture should be
4466  * stored using a specific format, namely avctx.pix_fmt.
4467  *
4468  * @param avctx the codec context
4469  * @param[out] buf the output buffer for the bitstream of encoded frame
4470  * @param[in] buf_size the size of the output buffer in bytes
4471  * @param[in] pict the input picture to encode
4472  * @return On error a negative value is returned, on success zero or the number
4473  * of bytes used from the output buffer.
4474  */
4475 attribute_deprecated
4476 int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size,
4477                          const AVFrame *pict);
4478 #endif
4479 
4480 /**
4481  * Encode a frame of video.
4482  *
4483  * Takes input raw video data from frame and writes the next output packet, if
4484  * available, to avpkt. The output packet does not necessarily contain data for
4485  * the most recent frame, as encoders can delay and reorder input frames
4486  * internally as needed.
4487  *
4488  * @param avctx     codec context
4489  * @param avpkt     output AVPacket.
4490  *                  The user can supply an output buffer by setting
4491  *                  avpkt->data and avpkt->size prior to calling the
4492  *                  function, but if the size of the user-provided data is not
4493  *                  large enough, encoding will fail. All other AVPacket fields
4494  *                  will be reset by the encoder using av_init_packet(). If
4495  *                  avpkt->data is NULL, the encoder will allocate it.
4496  *                  The encoder will set avpkt->size to the size of the
4497  *                  output packet. The returned data (if any) belongs to the
4498  *                  caller, he is responsible for freeing it.
4499  *
4500  *                  If this function fails or produces no output, avpkt will be
4501  *                  freed using av_free_packet() (i.e. avpkt->destruct will be
4502  *                  called to free the user supplied buffer).
4503  * @param[in] frame AVFrame containing the raw video data to be encoded.
4504  *                  May be NULL when flushing an encoder that has the
4505  *                  CODEC_CAP_DELAY capability set.
4506  * @param[out] got_packet_ptr This field is set to 1 by libavcodec if the
4507  *                            output packet is non-empty, and to 0 if it is
4508  *                            empty. If the function returns an error, the
4509  *                            packet can be assumed to be invalid, and the
4510  *                            value of got_packet_ptr is undefined and should
4511  *                            not be used.
4512  * @return          0 on success, negative error code on failure
4513  */
4514 int avcodec_encode_video2(AVCodecContext *avctx, AVPacket *avpkt,
4515                           const AVFrame *frame, int *got_packet_ptr);
4516 
4517 int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
4518                             const AVSubtitle *sub);
4519 
4520 
4521 /**
4522  * @}
4523  */
4524 
4525 #if FF_API_AVCODEC_RESAMPLE
4526 /**
4527  * @defgroup lavc_resample Audio resampling
4528  * @ingroup libavc
4529  * @deprecated use libswresample instead
4530  *
4531  * @{
4532  */
4533 struct ReSampleContext;
4534 struct AVResampleContext;
4535 
4536 typedef struct ReSampleContext ReSampleContext;
4537 
4538 /**
4539  *  Initialize audio resampling context.
4540  *
4541  * @param output_channels  number of output channels
4542  * @param input_channels   number of input channels
4543  * @param output_rate      output sample rate
4544  * @param input_rate       input sample rate
4545  * @param sample_fmt_out   requested output sample format
4546  * @param sample_fmt_in    input sample format
4547  * @param filter_length    length of each FIR filter in the filterbank relative to the cutoff frequency
4548  * @param log2_phase_count log2 of the number of entries in the polyphase filterbank
4549  * @param linear           if 1 then the used FIR filter will be linearly interpolated
4550                            between the 2 closest, if 0 the closest will be used
4551  * @param cutoff           cutoff frequency, 1.0 corresponds to half the output sampling rate
4552  * @return allocated ReSampleContext, NULL if error occurred
4553  */
4554 attribute_deprecated
4555 ReSampleContext *av_audio_resample_init(int output_channels, int input_channels,
4556                                         int output_rate, int input_rate,
4557                                         enum AVSampleFormat sample_fmt_out,
4558                                         enum AVSampleFormat sample_fmt_in,
4559                                         int filter_length, int log2_phase_count,
4560                                         int linear, double cutoff);
4561 
4562 attribute_deprecated
4563 int audio_resample(ReSampleContext *s, short *output, short *input, int nb_samples);
4564 
4565 /**
4566  * Free resample context.
4567  *
4568  * @param s a non-NULL pointer to a resample context previously
4569  *          created with av_audio_resample_init()
4570  */
4571 attribute_deprecated
4572 void audio_resample_close(ReSampleContext *s);
4573 
4574 
4575 /**
4576  * Initialize an audio resampler.
4577  * Note, if either rate is not an integer then simply scale both rates up so they are.
4578  * @param filter_length length of each FIR filter in the filterbank relative to the cutoff freq
4579  * @param log2_phase_count log2 of the number of entries in the polyphase filterbank
4580  * @param linear If 1 then the used FIR filter will be linearly interpolated
4581                  between the 2 closest, if 0 the closest will be used
4582  * @param cutoff cutoff frequency, 1.0 corresponds to half the output sampling rate
4583  */
4584 attribute_deprecated
4585 struct AVResampleContext *av_resample_init(int out_rate, int in_rate, int filter_length, int log2_phase_count, int linear, double cutoff);
4586 
4587 /**
4588  * Resample an array of samples using a previously configured context.
4589  * @param src an array of unconsumed samples
4590  * @param consumed the number of samples of src which have been consumed are returned here
4591  * @param src_size the number of unconsumed samples available
4592  * @param dst_size the amount of space in samples available in dst
4593  * @param update_ctx If this is 0 then the context will not be modified, that way several channels can be resampled with the same context.
4594  * @return the number of samples written in dst or -1 if an error occurred
4595  */
4596 attribute_deprecated
4597 int av_resample(struct AVResampleContext *c, short *dst, short *src, int *consumed, int src_size, int dst_size, int update_ctx);
4598 
4599 
4600 /**
4601  * Compensate samplerate/timestamp drift. The compensation is done by changing
4602  * the resampler parameters, so no audible clicks or similar distortions occur
4603  * @param compensation_distance distance in output samples over which the compensation should be performed
4604  * @param sample_delta number of output samples which should be output less
4605  *
4606  * example: av_resample_compensate(c, 10, 500)
4607  * here instead of 510 samples only 500 samples would be output
4608  *
4609  * note, due to rounding the actual compensation might be slightly different,
4610  * especially if the compensation_distance is large and the in_rate used during init is small
4611  */
4612 attribute_deprecated
4613 void av_resample_compensate(struct AVResampleContext *c, int sample_delta, int compensation_distance);
4614 attribute_deprecated
4615 void av_resample_close(struct AVResampleContext *c);
4616 
4617 /**
4618  * @}
4619  */
4620 #endif
4621 
4622 /**
4623  * @addtogroup lavc_picture
4624  * @{
4625  */
4626 
4627 /**
4628  * Allocate memory for the pixels of a picture and setup the AVPicture
4629  * fields for it.
4630  *
4631  * Call avpicture_free() to free it.
4632  *
4633  * @param picture            the picture structure to be filled in
4634  * @param pix_fmt            the pixel format of the picture
4635  * @param width              the width of the picture
4636  * @param height             the height of the picture
4637  * @return zero if successful, a negative error code otherwise
4638  *
4639  * @see av_image_alloc(), avpicture_fill()
4640  */
4641 int avpicture_alloc(AVPicture *picture, enum AVPixelFormat pix_fmt, int width, int height);
4642 
4643 /**
4644  * Free a picture previously allocated by avpicture_alloc().
4645  * The data buffer used by the AVPicture is freed, but the AVPicture structure
4646  * itself is not.
4647  *
4648  * @param picture the AVPicture to be freed
4649  */
4650 void avpicture_free(AVPicture *picture);
4651 
4652 /**
4653  * Setup the picture fields based on the specified image parameters
4654  * and the provided image data buffer.
4655  *
4656  * The picture fields are filled in by using the image data buffer
4657  * pointed to by ptr.
4658  *
4659  * If ptr is NULL, the function will fill only the picture linesize
4660  * array and return the required size for the image buffer.
4661  *
4662  * To allocate an image buffer and fill the picture data in one call,
4663  * use avpicture_alloc().
4664  *
4665  * @param picture       the picture to be filled in
4666  * @param ptr           buffer where the image data is stored, or NULL
4667  * @param pix_fmt       the pixel format of the image
4668  * @param width         the width of the image in pixels
4669  * @param height        the height of the image in pixels
4670  * @return the size in bytes required for src, a negative error code
4671  * in case of failure
4672  *
4673  * @see av_image_fill_arrays()
4674  */
4675 int avpicture_fill(AVPicture *picture, const uint8_t *ptr,
4676                    enum AVPixelFormat pix_fmt, int width, int height);
4677 
4678 /**
4679  * Copy pixel data from an AVPicture into a buffer.
4680  *
4681  * avpicture_get_size() can be used to compute the required size for
4682  * the buffer to fill.
4683  *
4684  * @param src        source picture with filled data
4685  * @param pix_fmt    picture pixel format
4686  * @param width      picture width
4687  * @param height     picture height
4688  * @param dest       destination buffer
4689  * @param dest_size  destination buffer size in bytes
4690  * @return the number of bytes written to dest, or a negative value
4691  * (error code) on error, for example if the destination buffer is not
4692  * big enough
4693  *
4694  * @see av_image_copy_to_buffer()
4695  */
4696 int avpicture_layout(const AVPicture *src, enum AVPixelFormat pix_fmt,
4697                      int width, int height,
4698                      unsigned char *dest, int dest_size);
4699 
4700 /**
4701  * Calculate the size in bytes that a picture of the given width and height
4702  * would occupy if stored in the given picture format.
4703  *
4704  * @param pix_fmt    picture pixel format
4705  * @param width      picture width
4706  * @param height     picture height
4707  * @return the computed picture buffer size or a negative error code
4708  * in case of error
4709  *
4710  * @see av_image_get_buffer_size().
4711  */
4712 int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height);
4713 
4714 #if FF_API_DEINTERLACE
4715 /**
4716  *  deinterlace - if not supported return -1
4717  *
4718  * @deprecated - use yadif (in libavfilter) instead
4719  */
4720 attribute_deprecated
4721 int avpicture_deinterlace(AVPicture *dst, const AVPicture *src,
4722                           enum AVPixelFormat pix_fmt, int width, int height);
4723 #endif
4724 /**
4725  * Copy image src to dst. Wraps av_image_copy().
4726  */
4727 void av_picture_copy(AVPicture *dst, const AVPicture *src,
4728                      enum AVPixelFormat pix_fmt, int width, int height);
4729 
4730 /**
4731  * Crop image top and left side.
4732  */
4733 int av_picture_crop(AVPicture *dst, const AVPicture *src,
4734                     enum AVPixelFormat pix_fmt, int top_band, int left_band);
4735 
4736 /**
4737  * Pad image.
4738  */
4739 int av_picture_pad(AVPicture *dst, const AVPicture *src, int height, int width, enum AVPixelFormat pix_fmt,
4740             int padtop, int padbottom, int padleft, int padright, int *color);
4741 
4742 /**
4743  * @}
4744  */
4745 
4746 /**
4747  * @defgroup lavc_misc Utility functions
4748  * @ingroup libavc
4749  *
4750  * Miscellaneous utility functions related to both encoding and decoding
4751  * (or neither).
4752  * @{
4753  */
4754 
4755 /**
4756  * @defgroup lavc_misc_pixfmt Pixel formats
4757  *
4758  * Functions for working with pixel formats.
4759  * @{
4760  */
4761 
4762 /**
4763  * Utility function to access log2_chroma_w log2_chroma_h from
4764  * the pixel format AVPixFmtDescriptor.
4765  *
4766  * This function asserts that pix_fmt is valid. See av_pix_fmt_get_chroma_sub_sample
4767  * for one that returns a failure code and continues in case of invalid
4768  * pix_fmts.
4769  *
4770  * @param[in]  pix_fmt the pixel format
4771  * @param[out] h_shift store log2_chroma_w
4772  * @param[out] v_shift store log2_chroma_h
4773  *
4774  * @see av_pix_fmt_get_chroma_sub_sample
4775  */
4776 
4777 void avcodec_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift);
4778 
4779 /**
4780  * Return a value representing the fourCC code associated to the
4781  * pixel format pix_fmt, or 0 if no associated fourCC code can be
4782  * found.
4783  */
4784 unsigned int avcodec_pix_fmt_to_codec_tag(enum AVPixelFormat pix_fmt);
4785 
4786 /**
4787  * @deprecated see av_get_pix_fmt_loss()
4788  */
4789 int avcodec_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt, enum AVPixelFormat src_pix_fmt,
4790                              int has_alpha);
4791 
4792 /**
4793  * Find the best pixel format to convert to given a certain source pixel
4794  * format.  When converting from one pixel format to another, information loss
4795  * may occur.  For example, when converting from RGB24 to GRAY, the color
4796  * information will be lost. Similarly, other losses occur when converting from
4797  * some formats to other formats. avcodec_find_best_pix_fmt_of_2() searches which of
4798  * the given pixel formats should be used to suffer the least amount of loss.
4799  * The pixel formats from which it chooses one, are determined by the
4800  * pix_fmt_list parameter.
4801  *
4802  *
4803  * @param[in] pix_fmt_list AV_PIX_FMT_NONE terminated array of pixel formats to choose from
4804  * @param[in] src_pix_fmt source pixel format
4805  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
4806  * @param[out] loss_ptr Combination of flags informing you what kind of losses will occur.
4807  * @return The best pixel format to convert to or -1 if none was found.
4808  */
4809 enum AVPixelFormat avcodec_find_best_pix_fmt_of_list(const enum AVPixelFormat *pix_fmt_list,
4810                                             enum AVPixelFormat src_pix_fmt,
4811                                             int has_alpha, int *loss_ptr);
4812 
4813 /**
4814  * @deprecated see av_find_best_pix_fmt_of_2()
4815  */
4816 enum AVPixelFormat avcodec_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
4817                                             enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
4818 
4819 attribute_deprecated
4820 #if AV_HAVE_INCOMPATIBLE_LIBAV_ABI
4821 enum AVPixelFormat avcodec_find_best_pix_fmt2(const enum AVPixelFormat *pix_fmt_list,
4822                                               enum AVPixelFormat src_pix_fmt,
4823                                               int has_alpha, int *loss_ptr);
4824 #else
4825 enum AVPixelFormat avcodec_find_best_pix_fmt2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
4826                                             enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
4827 #endif
4828 
4829 
4830 enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum AVPixelFormat * fmt);
4831 
4832 /**
4833  * @}
4834  */
4835 
4836 #if FF_API_SET_DIMENSIONS
4837 /**
4838  * @deprecated this function is not supposed to be used from outside of lavc
4839  */
4840 attribute_deprecated
4841 void avcodec_set_dimensions(AVCodecContext *s, int width, int height);
4842 #endif
4843 
4844 /**
4845  * Put a string representing the codec tag codec_tag in buf.
4846  *
4847  * @param buf       buffer to place codec tag in
4848  * @param buf_size size in bytes of buf
4849  * @param codec_tag codec tag to assign
4850  * @return the length of the string that would have been generated if
4851  * enough space had been available, excluding the trailing null
4852  */
4853 size_t av_get_codec_tag_string(char *buf, size_t buf_size, unsigned int codec_tag);
4854 
4855 void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode);
4856 
4857 /**
4858  * Return a name for the specified profile, if available.
4859  *
4860  * @param codec the codec that is searched for the given profile
4861  * @param profile the profile value for which a name is requested
4862  * @return A name for the profile if found, NULL otherwise.
4863  */
4864 const char *av_get_profile_name(const AVCodec *codec, int profile);
4865 
4866 int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size);
4867 int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2, int, int),void *arg, int *ret, int count);
4868 //FIXME func typedef
4869 
4870 /**
4871  * Fill AVFrame audio data and linesize pointers.
4872  *
4873  * The buffer buf must be a preallocated buffer with a size big enough
4874  * to contain the specified samples amount. The filled AVFrame data
4875  * pointers will point to this buffer.
4876  *
4877  * AVFrame extended_data channel pointers are allocated if necessary for
4878  * planar audio.
4879  *
4880  * @param frame       the AVFrame
4881  *                    frame->nb_samples must be set prior to calling the
4882  *                    function. This function fills in frame->data,
4883  *                    frame->extended_data, frame->linesize[0].
4884  * @param nb_channels channel count
4885  * @param sample_fmt  sample format
4886  * @param buf         buffer to use for frame data
4887  * @param buf_size    size of buffer
4888  * @param align       plane size sample alignment (0 = default)
4889  * @return            >=0 on success, negative error code on failure
4890  * @todo return the size in bytes required to store the samples in
4891  * case of success, at the next libavutil bump
4892  */
4893 int avcodec_fill_audio_frame(AVFrame *frame, int nb_channels,
4894                              enum AVSampleFormat sample_fmt, const uint8_t *buf,
4895                              int buf_size, int align);
4896 
4897 /**
4898  * Reset the internal decoder state / flush internal buffers. Should be called
4899  * e.g. when seeking or when switching to a different stream.
4900  *
4901  * @note when refcounted frames are not used (i.e. avctx->refcounted_frames is 0),
4902  * this invalidates the frames previously returned from the decoder. When
4903  * refcounted frames are used, the decoder just releases any references it might
4904  * keep internally, but the caller's reference remains valid.
4905  */
4906 void avcodec_flush_buffers(AVCodecContext *avctx);
4907 
4908 /**
4909  * Return codec bits per sample.
4910  *
4911  * @param[in] codec_id the codec
4912  * @return Number of bits per sample or zero if unknown for the given codec.
4913  */
4914 int av_get_bits_per_sample(enum AVCodecID codec_id);
4915 
4916 /**
4917  * Return the PCM codec associated with a sample format.
4918  * @param be  endianness, 0 for little, 1 for big,
4919  *            -1 (or anything else) for native
4920  * @return  AV_CODEC_ID_PCM_* or AV_CODEC_ID_NONE
4921  */
4922 enum AVCodecID av_get_pcm_codec(enum AVSampleFormat fmt, int be);
4923 
4924 /**
4925  * Return codec bits per sample.
4926  * Only return non-zero if the bits per sample is exactly correct, not an
4927  * approximation.
4928  *
4929  * @param[in] codec_id the codec
4930  * @return Number of bits per sample or zero if unknown for the given codec.
4931  */
4932 int av_get_exact_bits_per_sample(enum AVCodecID codec_id);
4933 
4934 /**
4935  * Return audio frame duration.
4936  *
4937  * @param avctx        codec context
4938  * @param frame_bytes  size of the frame, or 0 if unknown
4939  * @return             frame duration, in samples, if known. 0 if not able to
4940  *                     determine.
4941  */
4942 int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes);
4943 
4944 
4945 typedef struct AVBitStreamFilterContext {
4946     void *priv_data;
4947     struct AVBitStreamFilter *filter;
4948     AVCodecParserContext *parser;
4949     struct AVBitStreamFilterContext *next;
4950 } AVBitStreamFilterContext;
4951 
4952 
4953 typedef struct AVBitStreamFilter {
4954     const char *name;
4955     int priv_data_size;
4956     int (*filter)(AVBitStreamFilterContext *bsfc,
4957                   AVCodecContext *avctx, const char *args,
4958                   uint8_t **poutbuf, int *poutbuf_size,
4959                   const uint8_t *buf, int buf_size, int keyframe);
4960     void (*close)(AVBitStreamFilterContext *bsfc);
4961     struct AVBitStreamFilter *next;
4962 } AVBitStreamFilter;
4963 
4964 /**
4965  * Register a bitstream filter.
4966  *
4967  * The filter will be accessible to the application code through
4968  * av_bitstream_filter_next() or can be directly initialized with
4969  * av_bitstream_filter_init().
4970  *
4971  * @see avcodec_register_all()
4972  */
4973 void av_register_bitstream_filter(AVBitStreamFilter *bsf);
4974 
4975 /**
4976  * Create and initialize a bitstream filter context given a bitstream
4977  * filter name.
4978  *
4979  * The returned context must be freed with av_bitstream_filter_close().
4980  *
4981  * @param name    the name of the bitstream filter
4982  * @return a bitstream filter context if a matching filter was found
4983  * and successfully initialized, NULL otherwise
4984  */
4985 AVBitStreamFilterContext *av_bitstream_filter_init(const char *name);
4986 
4987 /**
4988  * Filter bitstream.
4989  *
4990  * This function filters the buffer buf with size buf_size, and places the
4991  * filtered buffer in the buffer pointed to by poutbuf.
4992  *
4993  * The output buffer must be freed by the caller.
4994  *
4995  * @param bsfc            bitstream filter context created by av_bitstream_filter_init()
4996  * @param avctx           AVCodecContext accessed by the filter, may be NULL.
4997  *                        If specified, this must point to the encoder context of the
4998  *                        output stream the packet is sent to.
4999  * @param args            arguments which specify the filter configuration, may be NULL
5000  * @param poutbuf         pointer which is updated to point to the filtered buffer
5001  * @param poutbuf_size    pointer which is updated to the filtered buffer size in bytes
5002  * @param buf             buffer containing the data to filter
5003  * @param buf_size        size in bytes of buf
5004  * @param keyframe        set to non-zero if the buffer to filter corresponds to a key-frame packet data
5005  * @return >= 0 in case of success, or a negative error code in case of failure
5006  *
5007  * If the return value is positive, an output buffer is allocated and
5008  * is available in *poutbuf, and is distinct from the input buffer.
5009  *
5010  * If the return value is 0, the output buffer is not allocated and
5011  * should be considered identical to the input buffer, or in case
5012  * *poutbuf was set it points to the input buffer (not necessarily to
5013  * its starting address).
5014  */
5015 int av_bitstream_filter_filter(AVBitStreamFilterContext *bsfc,
5016                                AVCodecContext *avctx, const char *args,
5017                                uint8_t **poutbuf, int *poutbuf_size,
5018                                const uint8_t *buf, int buf_size, int keyframe);
5019 
5020 /**
5021  * Release bitstream filter context.
5022  *
5023  * @param bsf the bitstream filter context created with
5024  * av_bitstream_filter_init(), can be NULL
5025  */
5026 void av_bitstream_filter_close(AVBitStreamFilterContext *bsf);
5027 
5028 /**
5029  * If f is NULL, return the first registered bitstream filter,
5030  * if f is non-NULL, return the next registered bitstream filter
5031  * after f, or NULL if f is the last one.
5032  *
5033  * This function can be used to iterate over all registered bitstream
5034  * filters.
5035  */
5036 AVBitStreamFilter *av_bitstream_filter_next(const AVBitStreamFilter *f);
5037 
5038 /* memory */
5039 
5040 /**
5041  * Same behaviour av_fast_malloc but the buffer has additional
5042  * FF_INPUT_BUFFER_PADDING_SIZE at the end which will always be 0.
5043  *
5044  * In addition the whole buffer will initially and after resizes
5045  * be 0-initialized so that no uninitialized data will ever appear.
5046  */
5047 void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size);
5048 
5049 /**
5050  * Same behaviour av_fast_padded_malloc except that buffer will always
5051  * be 0-initialized after call.
5052  */
5053 void av_fast_padded_mallocz(void *ptr, unsigned int *size, size_t min_size);
5054 
5055 /**
5056  * Encode extradata length to a buffer. Used by xiph codecs.
5057  *
5058  * @param s buffer to write to; must be at least (v/255+1) bytes long
5059  * @param v size of extradata in bytes
5060  * @return number of bytes written to the buffer.
5061  */
5062 unsigned int av_xiphlacing(unsigned char *s, unsigned int v);
5063 
5064 #if FF_API_MISSING_SAMPLE
5065 /**
5066  * Log a generic warning message about a missing feature. This function is
5067  * intended to be used internally by FFmpeg (libavcodec, libavformat, etc.)
5068  * only, and would normally not be used by applications.
5069  * @param[in] avc a pointer to an arbitrary struct of which the first field is
5070  * a pointer to an AVClass struct
5071  * @param[in] feature string containing the name of the missing feature
5072  * @param[in] want_sample indicates if samples are wanted which exhibit this feature.
5073  * If want_sample is non-zero, additional verbage will be added to the log
5074  * message which tells the user how to report samples to the development
5075  * mailing list.
5076  * @deprecated Use avpriv_report_missing_feature() instead.
5077  */
5078 attribute_deprecated
5079 void av_log_missing_feature(void *avc, const char *feature, int want_sample);
5080 
5081 /**
5082  * Log a generic warning message asking for a sample. This function is
5083  * intended to be used internally by FFmpeg (libavcodec, libavformat, etc.)
5084  * only, and would normally not be used by applications.
5085  * @param[in] avc a pointer to an arbitrary struct of which the first field is
5086  * a pointer to an AVClass struct
5087  * @param[in] msg string containing an optional message, or NULL if no message
5088  * @deprecated Use avpriv_request_sample() instead.
5089  */
5090 attribute_deprecated
5091 void av_log_ask_for_sample(void *avc, const char *msg, ...) av_printf_format(2, 3);
5092 #endif /* FF_API_MISSING_SAMPLE */
5093 
5094 /**
5095  * Register the hardware accelerator hwaccel.
5096  */
5097 void av_register_hwaccel(AVHWAccel *hwaccel);
5098 
5099 /**
5100  * If hwaccel is NULL, returns the first registered hardware accelerator,
5101  * if hwaccel is non-NULL, returns the next registered hardware accelerator
5102  * after hwaccel, or NULL if hwaccel is the last one.
5103  */
5104 AVHWAccel *av_hwaccel_next(const AVHWAccel *hwaccel);
5105 
5106 
5107 /**
5108  * Lock operation used by lockmgr
5109  */
5110 enum AVLockOp {
5111   AV_LOCK_CREATE,  ///< Create a mutex
5112   AV_LOCK_OBTAIN,  ///< Lock the mutex
5113   AV_LOCK_RELEASE, ///< Unlock the mutex
5114   AV_LOCK_DESTROY, ///< Free mutex resources
5115 };
5116 
5117 /**
5118  * Register a user provided lock manager supporting the operations
5119  * specified by AVLockOp. mutex points to a (void *) where the
5120  * lockmgr should store/get a pointer to a user allocated mutex. It's
5121  * NULL upon AV_LOCK_CREATE and != NULL for all other ops.
5122  *
5123  * @param cb User defined callback. Note: FFmpeg may invoke calls to this
5124  *           callback during the call to av_lockmgr_register().
5125  *           Thus, the application must be prepared to handle that.
5126  *           If cb is set to NULL the lockmgr will be unregistered.
5127  *           Also note that during unregistration the previously registered
5128  *           lockmgr callback may also be invoked.
5129  */
5130 int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op));
5131 
5132 /**
5133  * Get the type of the given codec.
5134  */
5135 enum AVMediaType avcodec_get_type(enum AVCodecID codec_id);
5136 
5137 /**
5138  * Get the name of a codec.
5139  * @return  a static string identifying the codec; never NULL
5140  */
5141 const char *avcodec_get_name(enum AVCodecID id);
5142 
5143 /**
5144  * @return a positive value if s is open (i.e. avcodec_open2() was called on it
5145  * with no corresponding avcodec_close()), 0 otherwise.
5146  */
5147 int avcodec_is_open(AVCodecContext *s);
5148 
5149 /**
5150  * @return a non-zero number if codec is an encoder, zero otherwise
5151  */
5152 int av_codec_is_encoder(const AVCodec *codec);
5153 
5154 /**
5155  * @return a non-zero number if codec is a decoder, zero otherwise
5156  */
5157 int av_codec_is_decoder(const AVCodec *codec);
5158 
5159 /**
5160  * @return descriptor for given codec ID or NULL if no descriptor exists.
5161  */
5162 const AVCodecDescriptor *avcodec_descriptor_get(enum AVCodecID id);
5163 
5164 /**
5165  * Iterate over all codec descriptors known to libavcodec.
5166  *
5167  * @param prev previous descriptor. NULL to get the first descriptor.
5168  *
5169  * @return next descriptor or NULL after the last descriptor
5170  */
5171 const AVCodecDescriptor *avcodec_descriptor_next(const AVCodecDescriptor *prev);
5172 
5173 /**
5174  * @return codec descriptor with the given name or NULL if no such descriptor
5175  *         exists.
5176  */
5177 const AVCodecDescriptor *avcodec_descriptor_get_by_name(const char *name);
5178 
5179 /**
5180  * @}
5181  */
5182 
5183 #endif /* AVCODEC_AVCODEC_H */
5184