1 /*
2  * copyright (c) 2001 Fabrice Bellard
3  *
4  * This file is part of Libav.
5  *
6  * Libav 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  * Libav 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 Libav; 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  * external API header
27  */
28 
29 #include <errno.h>
30 #include "libavutil/samplefmt.h"
31 #include "libavutil/avutil.h"
32 #include "libavutil/cpu.h"
33 #include "libavutil/dict.h"
34 #include "libavutil/log.h"
35 #include "libavutil/pixfmt.h"
36 #include "libavutil/rational.h"
37 
38 #include "libavcodec/version.h"
39 /**
40  * @defgroup libavc Encoding/Decoding Library
41  * @{
42  *
43  * @defgroup lavc_decoding Decoding
44  * @{
45  * @}
46  *
47  * @defgroup lavc_encoding Encoding
48  * @{
49  * @}
50  *
51  * @defgroup lavc_codec Codecs
52  * @{
53  * @defgroup lavc_codec_native Native Codecs
54  * @{
55  * @}
56  * @defgroup lavc_codec_wrappers External library wrappers
57  * @{
58  * @}
59  * @defgroup lavc_codec_hwaccel Hardware Accelerators bridge
60  * @{
61  * @}
62  * @}
63  * @defgroup lavc_internal Internal
64  * @{
65  * @}
66  * @}
67  *
68  */
69 
70 
71 /**
72  * Identify the syntax and semantics of the bitstream.
73  * The principle is roughly:
74  * Two decoders with the same ID can decode the same streams.
75  * Two encoders with the same ID can encode compatible streams.
76  * There may be slight deviations from the principle due to implementation
77  * details.
78  *
79  * If you add a codec ID to this list, add it so that
80  * 1. no value of a existing codec ID changes (that would break ABI),
81  * 2. it is as close as possible to similar codecs.
82  */
83 enum CodecID {
84     CODEC_ID_NONE,
85 
86     /* video codecs */
87     CODEC_ID_MPEG1VIDEO,
88     CODEC_ID_MPEG2VIDEO, ///< preferred ID for MPEG-1/2 video decoding
89     CODEC_ID_MPEG2VIDEO_XVMC,
90     CODEC_ID_H261,
91     CODEC_ID_H263,
92     CODEC_ID_RV10,
93     CODEC_ID_RV20,
94     CODEC_ID_MJPEG,
95     CODEC_ID_MJPEGB,
96     CODEC_ID_LJPEG,
97     CODEC_ID_SP5X,
98     CODEC_ID_JPEGLS,
99     CODEC_ID_MPEG4,
100     CODEC_ID_RAWVIDEO,
101     CODEC_ID_MSMPEG4V1,
102     CODEC_ID_MSMPEG4V2,
103     CODEC_ID_MSMPEG4V3,
104     CODEC_ID_WMV1,
105     CODEC_ID_WMV2,
106     CODEC_ID_H263P,
107     CODEC_ID_H263I,
108     CODEC_ID_FLV1,
109     CODEC_ID_SVQ1,
110     CODEC_ID_SVQ3,
111     CODEC_ID_DVVIDEO,
112     CODEC_ID_HUFFYUV,
113     CODEC_ID_CYUV,
114     CODEC_ID_H264,
115     CODEC_ID_INDEO3,
116     CODEC_ID_VP3,
117     CODEC_ID_THEORA,
118     CODEC_ID_ASV1,
119     CODEC_ID_ASV2,
120     CODEC_ID_FFV1,
121     CODEC_ID_4XM,
122     CODEC_ID_VCR1,
123     CODEC_ID_CLJR,
124     CODEC_ID_MDEC,
125     CODEC_ID_ROQ,
126     CODEC_ID_INTERPLAY_VIDEO,
127     CODEC_ID_XAN_WC3,
128     CODEC_ID_XAN_WC4,
129     CODEC_ID_RPZA,
130     CODEC_ID_CINEPAK,
131     CODEC_ID_WS_VQA,
132     CODEC_ID_MSRLE,
133     CODEC_ID_MSVIDEO1,
134     CODEC_ID_IDCIN,
135     CODEC_ID_8BPS,
136     CODEC_ID_SMC,
137     CODEC_ID_FLIC,
138     CODEC_ID_TRUEMOTION1,
139     CODEC_ID_VMDVIDEO,
140     CODEC_ID_MSZH,
141     CODEC_ID_ZLIB,
142     CODEC_ID_QTRLE,
143     CODEC_ID_SNOW,
144     CODEC_ID_TSCC,
145     CODEC_ID_ULTI,
146     CODEC_ID_QDRAW,
147     CODEC_ID_VIXL,
148     CODEC_ID_QPEG,
149     CODEC_ID_PNG,
150     CODEC_ID_PPM,
151     CODEC_ID_PBM,
152     CODEC_ID_PGM,
153     CODEC_ID_PGMYUV,
154     CODEC_ID_PAM,
155     CODEC_ID_FFVHUFF,
156     CODEC_ID_RV30,
157     CODEC_ID_RV40,
158     CODEC_ID_VC1,
159     CODEC_ID_WMV3,
160     CODEC_ID_LOCO,
161     CODEC_ID_WNV1,
162     CODEC_ID_AASC,
163     CODEC_ID_INDEO2,
164     CODEC_ID_FRAPS,
165     CODEC_ID_TRUEMOTION2,
166     CODEC_ID_BMP,
167     CODEC_ID_CSCD,
168     CODEC_ID_MMVIDEO,
169     CODEC_ID_ZMBV,
170     CODEC_ID_AVS,
171     CODEC_ID_SMACKVIDEO,
172     CODEC_ID_NUV,
173     CODEC_ID_KMVC,
174     CODEC_ID_FLASHSV,
175     CODEC_ID_CAVS,
176     CODEC_ID_JPEG2000,
177     CODEC_ID_VMNC,
178     CODEC_ID_VP5,
179     CODEC_ID_VP6,
180     CODEC_ID_VP6F,
181     CODEC_ID_TARGA,
182     CODEC_ID_DSICINVIDEO,
183     CODEC_ID_TIERTEXSEQVIDEO,
184     CODEC_ID_TIFF,
185     CODEC_ID_GIF,
186 #if LIBAVCODEC_VERSION_MAJOR == 53
187     CODEC_ID_FFH264,
188 #endif
189     CODEC_ID_DXA,
190     CODEC_ID_DNXHD,
191     CODEC_ID_THP,
192     CODEC_ID_SGI,
193     CODEC_ID_C93,
194     CODEC_ID_BETHSOFTVID,
195     CODEC_ID_PTX,
196     CODEC_ID_TXD,
197     CODEC_ID_VP6A,
198     CODEC_ID_AMV,
199     CODEC_ID_VB,
200     CODEC_ID_PCX,
201     CODEC_ID_SUNRAST,
202     CODEC_ID_INDEO4,
203     CODEC_ID_INDEO5,
204     CODEC_ID_MIMIC,
205     CODEC_ID_RL2,
206 #if LIBAVCODEC_VERSION_MAJOR == 53
207     CODEC_ID_8SVX_EXP,
208     CODEC_ID_8SVX_FIB,
209 #endif
210     CODEC_ID_ESCAPE124,
211     CODEC_ID_DIRAC,
212     CODEC_ID_BFI,
213     CODEC_ID_CMV,
214     CODEC_ID_MOTIONPIXELS,
215     CODEC_ID_TGV,
216     CODEC_ID_TGQ,
217     CODEC_ID_TQI,
218     CODEC_ID_AURA,
219     CODEC_ID_AURA2,
220     CODEC_ID_V210X,
221     CODEC_ID_TMV,
222     CODEC_ID_V210,
223     CODEC_ID_DPX,
224     CODEC_ID_MAD,
225     CODEC_ID_FRWU,
226     CODEC_ID_FLASHSV2,
227     CODEC_ID_CDGRAPHICS,
228     CODEC_ID_R210,
229     CODEC_ID_ANM,
230     CODEC_ID_BINKVIDEO,
231     CODEC_ID_IFF_ILBM,
232     CODEC_ID_IFF_BYTERUN1,
233     CODEC_ID_KGV1,
234     CODEC_ID_YOP,
235     CODEC_ID_VP8,
236     CODEC_ID_PICTOR,
237     CODEC_ID_ANSI,
238     CODEC_ID_A64_MULTI,
239     CODEC_ID_A64_MULTI5,
240     CODEC_ID_R10K,
241     CODEC_ID_MXPEG,
242     CODEC_ID_LAGARITH,
243     CODEC_ID_PRORES,
244     CODEC_ID_JV,
245     CODEC_ID_DFA,
246     CODEC_ID_WMV3IMAGE,
247     CODEC_ID_VC1IMAGE,
248 #if LIBAVCODEC_VERSION_MAJOR == 53
249     CODEC_ID_G723_1,
250     CODEC_ID_G729,
251 #endif
252     CODEC_ID_UTVIDEO,
253     CODEC_ID_BMV_VIDEO,
254     CODEC_ID_VBLE,
255     CODEC_ID_DXTORY,
256     CODEC_ID_V410,
257 
258     /* various PCM "codecs" */
259     CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
260     CODEC_ID_PCM_S16LE = 0x10000,
261     CODEC_ID_PCM_S16BE,
262     CODEC_ID_PCM_U16LE,
263     CODEC_ID_PCM_U16BE,
264     CODEC_ID_PCM_S8,
265     CODEC_ID_PCM_U8,
266     CODEC_ID_PCM_MULAW,
267     CODEC_ID_PCM_ALAW,
268     CODEC_ID_PCM_S32LE,
269     CODEC_ID_PCM_S32BE,
270     CODEC_ID_PCM_U32LE,
271     CODEC_ID_PCM_U32BE,
272     CODEC_ID_PCM_S24LE,
273     CODEC_ID_PCM_S24BE,
274     CODEC_ID_PCM_U24LE,
275     CODEC_ID_PCM_U24BE,
276     CODEC_ID_PCM_S24DAUD,
277     CODEC_ID_PCM_ZORK,
278     CODEC_ID_PCM_S16LE_PLANAR,
279     CODEC_ID_PCM_DVD,
280     CODEC_ID_PCM_F32BE,
281     CODEC_ID_PCM_F32LE,
282     CODEC_ID_PCM_F64BE,
283     CODEC_ID_PCM_F64LE,
284     CODEC_ID_PCM_BLURAY,
285     CODEC_ID_PCM_LXF,
286     CODEC_ID_S302M,
287     CODEC_ID_PCM_S8_PLANAR,
288 
289     /* various ADPCM codecs */
290     CODEC_ID_ADPCM_IMA_QT = 0x11000,
291     CODEC_ID_ADPCM_IMA_WAV,
292     CODEC_ID_ADPCM_IMA_DK3,
293     CODEC_ID_ADPCM_IMA_DK4,
294     CODEC_ID_ADPCM_IMA_WS,
295     CODEC_ID_ADPCM_IMA_SMJPEG,
296     CODEC_ID_ADPCM_MS,
297     CODEC_ID_ADPCM_4XM,
298     CODEC_ID_ADPCM_XA,
299     CODEC_ID_ADPCM_ADX,
300     CODEC_ID_ADPCM_EA,
301     CODEC_ID_ADPCM_G726,
302     CODEC_ID_ADPCM_CT,
303     CODEC_ID_ADPCM_SWF,
304     CODEC_ID_ADPCM_YAMAHA,
305     CODEC_ID_ADPCM_SBPRO_4,
306     CODEC_ID_ADPCM_SBPRO_3,
307     CODEC_ID_ADPCM_SBPRO_2,
308     CODEC_ID_ADPCM_THP,
309     CODEC_ID_ADPCM_IMA_AMV,
310     CODEC_ID_ADPCM_EA_R1,
311     CODEC_ID_ADPCM_EA_R3,
312     CODEC_ID_ADPCM_EA_R2,
313     CODEC_ID_ADPCM_IMA_EA_SEAD,
314     CODEC_ID_ADPCM_IMA_EA_EACS,
315     CODEC_ID_ADPCM_EA_XAS,
316     CODEC_ID_ADPCM_EA_MAXIS_XA,
317     CODEC_ID_ADPCM_IMA_ISS,
318     CODEC_ID_ADPCM_G722,
319 
320     /* AMR */
321     CODEC_ID_AMR_NB = 0x12000,
322     CODEC_ID_AMR_WB,
323 
324     /* RealAudio codecs*/
325     CODEC_ID_RA_144 = 0x13000,
326     CODEC_ID_RA_288,
327 
328     /* various DPCM codecs */
329     CODEC_ID_ROQ_DPCM = 0x14000,
330     CODEC_ID_INTERPLAY_DPCM,
331     CODEC_ID_XAN_DPCM,
332     CODEC_ID_SOL_DPCM,
333 
334     /* audio codecs */
335     CODEC_ID_MP2 = 0x15000,
336     CODEC_ID_MP3, ///< preferred ID for decoding MPEG audio layer 1, 2 or 3
337     CODEC_ID_AAC,
338     CODEC_ID_AC3,
339     CODEC_ID_DTS,
340     CODEC_ID_VORBIS,
341     CODEC_ID_DVAUDIO,
342     CODEC_ID_WMAV1,
343     CODEC_ID_WMAV2,
344     CODEC_ID_MACE3,
345     CODEC_ID_MACE6,
346     CODEC_ID_VMDAUDIO,
347 #if LIBAVCODEC_VERSION_MAJOR == 53
348     CODEC_ID_SONIC,
349     CODEC_ID_SONIC_LS,
350 #endif
351     CODEC_ID_FLAC,
352     CODEC_ID_MP3ADU,
353     CODEC_ID_MP3ON4,
354     CODEC_ID_SHORTEN,
355     CODEC_ID_ALAC,
356     CODEC_ID_WESTWOOD_SND1,
357     CODEC_ID_GSM, ///< as in Berlin toast format
358     CODEC_ID_QDM2,
359     CODEC_ID_COOK,
360     CODEC_ID_TRUESPEECH,
361     CODEC_ID_TTA,
362     CODEC_ID_SMACKAUDIO,
363     CODEC_ID_QCELP,
364     CODEC_ID_WAVPACK,
365     CODEC_ID_DSICINAUDIO,
366     CODEC_ID_IMC,
367     CODEC_ID_MUSEPACK7,
368     CODEC_ID_MLP,
369     CODEC_ID_GSM_MS, /* as found in WAV */
370     CODEC_ID_ATRAC3,
371     CODEC_ID_VOXWARE,
372     CODEC_ID_APE,
373     CODEC_ID_NELLYMOSER,
374     CODEC_ID_MUSEPACK8,
375     CODEC_ID_SPEEX,
376     CODEC_ID_WMAVOICE,
377     CODEC_ID_WMAPRO,
378     CODEC_ID_WMALOSSLESS,
379     CODEC_ID_ATRAC3P,
380     CODEC_ID_EAC3,
381     CODEC_ID_SIPR,
382     CODEC_ID_MP1,
383     CODEC_ID_TWINVQ,
384     CODEC_ID_TRUEHD,
385     CODEC_ID_MP4ALS,
386     CODEC_ID_ATRAC1,
387     CODEC_ID_BINKAUDIO_RDFT,
388     CODEC_ID_BINKAUDIO_DCT,
389     CODEC_ID_AAC_LATM,
390     CODEC_ID_QDMC,
391     CODEC_ID_CELT,
392 #if LIBAVCODEC_VERSION_MAJOR > 53
393     CODEC_ID_G723_1,
394     CODEC_ID_G729,
395     CODEC_ID_8SVX_EXP,
396     CODEC_ID_8SVX_FIB,
397 #endif
398     CODEC_ID_BMV_AUDIO,
399 
400     /* subtitle codecs */
401     CODEC_ID_FIRST_SUBTITLE = 0x17000,          ///< A dummy ID pointing at the start of subtitle codecs.
402     CODEC_ID_DVD_SUBTITLE = 0x17000,
403     CODEC_ID_DVB_SUBTITLE,
404     CODEC_ID_TEXT,  ///< raw UTF-8 text
405     CODEC_ID_XSUB,
406     CODEC_ID_SSA,
407     CODEC_ID_MOV_TEXT,
408     CODEC_ID_HDMV_PGS_SUBTITLE,
409     CODEC_ID_DVB_TELETEXT,
410     CODEC_ID_SRT,
411 
412     /* other specific kind of codecs (generally used for attachments) */
413     CODEC_ID_FIRST_UNKNOWN = 0x18000,           ///< A dummy ID pointing at the start of various fake codecs.
414     CODEC_ID_TTF = 0x18000,
415 
416     CODEC_ID_PROBE = 0x19000, ///< codec_id is not known (like CODEC_ID_NONE) but lavf should attempt to identify it
417 
418     CODEC_ID_MPEG2TS = 0x20000, /**< _FAKE_ codec to indicate a raw MPEG-2 TS
419                                 * stream (only used by libavformat) */
420     CODEC_ID_MPEG4SYSTEMS = 0x20001, /**< _FAKE_ codec to indicate a MPEG-4 Systems
421                                 * stream (only used by libavformat) */
422     CODEC_ID_FFMETADATA = 0x21000,   ///< Dummy codec for streams containing only metadata information.
423 };
424 
425 #if FF_API_OLD_SAMPLE_FMT
426 #define SampleFormat AVSampleFormat
427 
428 #define SAMPLE_FMT_NONE AV_SAMPLE_FMT_NONE
429 #define SAMPLE_FMT_U8   AV_SAMPLE_FMT_U8
430 #define SAMPLE_FMT_S16  AV_SAMPLE_FMT_S16
431 #define SAMPLE_FMT_S32  AV_SAMPLE_FMT_S32
432 #define SAMPLE_FMT_FLT  AV_SAMPLE_FMT_FLT
433 #define SAMPLE_FMT_DBL  AV_SAMPLE_FMT_DBL
434 #define SAMPLE_FMT_NB   AV_SAMPLE_FMT_NB
435 #endif
436 
437 #if FF_API_OLD_AUDIOCONVERT
438 #include "libavutil/audioconvert.h"
439 
440 /* Audio channel masks */
441 #define CH_FRONT_LEFT            AV_CH_FRONT_LEFT
442 #define CH_FRONT_RIGHT           AV_CH_FRONT_RIGHT
443 #define CH_FRONT_CENTER          AV_CH_FRONT_CENTER
444 #define CH_LOW_FREQUENCY         AV_CH_LOW_FREQUENCY
445 #define CH_BACK_LEFT             AV_CH_BACK_LEFT
446 #define CH_BACK_RIGHT            AV_CH_BACK_RIGHT
447 #define CH_FRONT_LEFT_OF_CENTER  AV_CH_FRONT_LEFT_OF_CENTER
448 #define CH_FRONT_RIGHT_OF_CENTER AV_CH_FRONT_RIGHT_OF_CENTER
449 #define CH_BACK_CENTER           AV_CH_BACK_CENTER
450 #define CH_SIDE_LEFT             AV_CH_SIDE_LEFT
451 #define CH_SIDE_RIGHT            AV_CH_SIDE_RIGHT
452 #define CH_TOP_CENTER            AV_CH_TOP_CENTER
453 #define CH_TOP_FRONT_LEFT        AV_CH_TOP_FRONT_LEFT
454 #define CH_TOP_FRONT_CENTER      AV_CH_TOP_FRONT_CENTER
455 #define CH_TOP_FRONT_RIGHT       AV_CH_TOP_FRONT_RIGHT
456 #define CH_TOP_BACK_LEFT         AV_CH_TOP_BACK_LEFT
457 #define CH_TOP_BACK_CENTER       AV_CH_TOP_BACK_CENTER
458 #define CH_TOP_BACK_RIGHT        AV_CH_TOP_BACK_RIGHT
459 #define CH_STEREO_LEFT           AV_CH_STEREO_LEFT
460 #define CH_STEREO_RIGHT          AV_CH_STEREO_RIGHT
461 
462 /** Channel mask value used for AVCodecContext.request_channel_layout
463     to indicate that the user requests the channel order of the decoder output
464     to be the native codec channel order. */
465 #define CH_LAYOUT_NATIVE         AV_CH_LAYOUT_NATIVE
466 
467 /* Audio channel convenience macros */
468 #define CH_LAYOUT_MONO           AV_CH_LAYOUT_MONO
469 #define CH_LAYOUT_STEREO         AV_CH_LAYOUT_STEREO
470 #define CH_LAYOUT_2_1            AV_CH_LAYOUT_2_1
471 #define CH_LAYOUT_SURROUND       AV_CH_LAYOUT_SURROUND
472 #define CH_LAYOUT_4POINT0        AV_CH_LAYOUT_4POINT0
473 #define CH_LAYOUT_2_2            AV_CH_LAYOUT_2_2
474 #define CH_LAYOUT_QUAD           AV_CH_LAYOUT_QUAD
475 #define CH_LAYOUT_5POINT0        AV_CH_LAYOUT_5POINT0
476 #define CH_LAYOUT_5POINT1        AV_CH_LAYOUT_5POINT1
477 #define CH_LAYOUT_5POINT0_BACK   AV_CH_LAYOUT_5POINT0_BACK
478 #define CH_LAYOUT_5POINT1_BACK   AV_CH_LAYOUT_5POINT1_BACK
479 #define CH_LAYOUT_7POINT0        AV_CH_LAYOUT_7POINT0
480 #define CH_LAYOUT_7POINT1        AV_CH_LAYOUT_7POINT1
481 #define CH_LAYOUT_7POINT1_WIDE   AV_CH_LAYOUT_7POINT1_WIDE
482 #define CH_LAYOUT_STEREO_DOWNMIX AV_CH_LAYOUT_STEREO_DOWNMIX
483 #endif
484 
485 #if FF_API_OLD_DECODE_AUDIO
486 /* in bytes */
487 #define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio
488 #endif
489 
490 /**
491  * Required number of additionally allocated bytes at the end of the input bitstream for decoding.
492  * This is mainly needed because some optimized bitstream readers read
493  * 32 or 64 bit at once and could read over the end.<br>
494  * Note: If the first 23 bits of the additional bytes are not 0, then damaged
495  * MPEG bitstreams could cause overread and segfault.
496  */
497 #define FF_INPUT_BUFFER_PADDING_SIZE 8
498 
499 /**
500  * minimum encoding buffer size
501  * Used to avoid some checks during header writing.
502  */
503 #define FF_MIN_BUFFER_SIZE 16384
504 
505 
506 /**
507  * motion estimation type.
508  */
509 enum Motion_Est_ID {
510     ME_ZERO = 1,    ///< no search, that is use 0,0 vector whenever one is needed
511     ME_FULL,
512     ME_LOG,
513     ME_PHODS,
514     ME_EPZS,        ///< enhanced predictive zonal search
515     ME_X1,          ///< reserved for experiments
516     ME_HEX,         ///< hexagon based search
517     ME_UMH,         ///< uneven multi-hexagon search
518     ME_ITER,        ///< iterative search
519     ME_TESA,        ///< transformed exhaustive search algorithm
520 };
521 
522 enum AVDiscard{
523     /* We leave some space between them for extensions (drop some
524      * keyframes for intra-only or drop just some bidir frames). */
525     AVDISCARD_NONE   =-16, ///< discard nothing
526     AVDISCARD_DEFAULT=  0, ///< discard useless packets like 0 size packets in avi
527     AVDISCARD_NONREF =  8, ///< discard all non reference
528     AVDISCARD_BIDIR  = 16, ///< discard all bidirectional frames
529     AVDISCARD_NONKEY = 32, ///< discard all frames except keyframes
530     AVDISCARD_ALL    = 48, ///< discard all
531 };
532 
533 enum AVColorPrimaries{
534     AVCOL_PRI_BT709      =1, ///< also ITU-R BT1361 / IEC 61966-2-4 / SMPTE RP177 Annex B
535     AVCOL_PRI_UNSPECIFIED=2,
536     AVCOL_PRI_BT470M     =4,
537     AVCOL_PRI_BT470BG    =5, ///< also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM
538     AVCOL_PRI_SMPTE170M  =6, ///< also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC
539     AVCOL_PRI_SMPTE240M  =7, ///< functionally identical to above
540     AVCOL_PRI_FILM       =8,
541     AVCOL_PRI_NB           , ///< Not part of ABI
542 };
543 
544 enum AVColorTransferCharacteristic{
545     AVCOL_TRC_BT709      =1, ///< also ITU-R BT1361
546     AVCOL_TRC_UNSPECIFIED=2,
547     AVCOL_TRC_GAMMA22    =4, ///< also ITU-R BT470M / ITU-R BT1700 625 PAL & SECAM
548     AVCOL_TRC_GAMMA28    =5, ///< also ITU-R BT470BG
549     AVCOL_TRC_NB           , ///< Not part of ABI
550 };
551 
552 enum AVColorSpace{
553     AVCOL_SPC_RGB        =0,
554     AVCOL_SPC_BT709      =1, ///< also ITU-R BT1361 / IEC 61966-2-4 xvYCC709 / SMPTE RP177 Annex B
555     AVCOL_SPC_UNSPECIFIED=2,
556     AVCOL_SPC_FCC        =4,
557     AVCOL_SPC_BT470BG    =5, ///< also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM / IEC 61966-2-4 xvYCC601
558     AVCOL_SPC_SMPTE170M  =6, ///< also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC / functionally identical to above
559     AVCOL_SPC_SMPTE240M  =7,
560     AVCOL_SPC_NB           , ///< Not part of ABI
561 };
562 
563 enum AVColorRange{
564     AVCOL_RANGE_UNSPECIFIED=0,
565     AVCOL_RANGE_MPEG       =1, ///< the normal 219*2^(n-8) "MPEG" YUV ranges
566     AVCOL_RANGE_JPEG       =2, ///< the normal     2^n-1   "JPEG" YUV ranges
567     AVCOL_RANGE_NB           , ///< Not part of ABI
568 };
569 
570 /**
571  *  X   X      3 4 X      X are luma samples,
572  *             1 2        1-6 are possible chroma positions
573  *  X   X      5 6 X      0 is undefined/unknown position
574  */
575 enum AVChromaLocation{
576     AVCHROMA_LOC_UNSPECIFIED=0,
577     AVCHROMA_LOC_LEFT       =1, ///< mpeg2/4, h264 default
578     AVCHROMA_LOC_CENTER     =2, ///< mpeg1, jpeg, h263
579     AVCHROMA_LOC_TOPLEFT    =3, ///< DV
580     AVCHROMA_LOC_TOP        =4,
581     AVCHROMA_LOC_BOTTOMLEFT =5,
582     AVCHROMA_LOC_BOTTOM     =6,
583     AVCHROMA_LOC_NB           , ///< Not part of ABI
584 };
585 
586 #if FF_API_FLAC_GLOBAL_OPTS
587 /**
588  * LPC analysis type
589  */
590 enum AVLPCType {
591     AV_LPC_TYPE_DEFAULT     = -1, ///< use the codec default LPC type
592     AV_LPC_TYPE_NONE        =  0, ///< do not use LPC prediction or use all zero coefficients
593     AV_LPC_TYPE_FIXED       =  1, ///< fixed LPC coefficients
594     AV_LPC_TYPE_LEVINSON    =  2, ///< Levinson-Durbin recursion
595     AV_LPC_TYPE_CHOLESKY    =  3, ///< Cholesky factorization
596     AV_LPC_TYPE_NB              , ///< Not part of ABI
597 };
598 #endif
599 
600 enum AVAudioServiceType {
601     AV_AUDIO_SERVICE_TYPE_MAIN              = 0,
602     AV_AUDIO_SERVICE_TYPE_EFFECTS           = 1,
603     AV_AUDIO_SERVICE_TYPE_VISUALLY_IMPAIRED = 2,
604     AV_AUDIO_SERVICE_TYPE_HEARING_IMPAIRED  = 3,
605     AV_AUDIO_SERVICE_TYPE_DIALOGUE          = 4,
606     AV_AUDIO_SERVICE_TYPE_COMMENTARY        = 5,
607     AV_AUDIO_SERVICE_TYPE_EMERGENCY         = 6,
608     AV_AUDIO_SERVICE_TYPE_VOICE_OVER        = 7,
609     AV_AUDIO_SERVICE_TYPE_KARAOKE           = 8,
610     AV_AUDIO_SERVICE_TYPE_NB                   , ///< Not part of ABI
611 };
612 
613 typedef struct RcOverride{
614     int start_frame;
615     int end_frame;
616     int qscale; // If this is 0 then quality_factor will be used instead.
617     float quality_factor;
618 } RcOverride;
619 
620 #define FF_MAX_B_FRAMES 16
621 
622 /* encoding support
623    These flags can be passed in AVCodecContext.flags before initialization.
624    Note: Not everything is supported yet.
625 */
626 
627 #define CODEC_FLAG_QSCALE 0x0002  ///< Use fixed qscale.
628 #define CODEC_FLAG_4MV    0x0004  ///< 4 MV per MB allowed / advanced prediction for H.263.
629 #define CODEC_FLAG_QPEL   0x0010  ///< Use qpel MC.
630 #define CODEC_FLAG_GMC    0x0020  ///< Use GMC.
631 #define CODEC_FLAG_MV0    0x0040  ///< Always try a MB with MV=<0,0>.
632 /**
633  * The parent program guarantees that the input for B-frames containing
634  * streams is not written to for at least s->max_b_frames+1 frames, if
635  * this is not set the input will be copied.
636  */
637 #define CODEC_FLAG_INPUT_PRESERVED 0x0100
638 #define CODEC_FLAG_PASS1           0x0200   ///< Use internal 2pass ratecontrol in first pass mode.
639 #define CODEC_FLAG_PASS2           0x0400   ///< Use internal 2pass ratecontrol in second pass mode.
640 #define CODEC_FLAG_GRAY            0x2000   ///< Only decode/encode grayscale.
641 #define CODEC_FLAG_EMU_EDGE        0x4000   ///< Don't draw edges.
642 #define CODEC_FLAG_PSNR            0x8000   ///< error[?] variables will be set during encoding.
643 #define CODEC_FLAG_TRUNCATED       0x00010000 /** Input bitstream might be truncated at a random
644                                                   location instead of only at frame boundaries. */
645 #define CODEC_FLAG_NORMALIZE_AQP  0x00020000 ///< Normalize adaptive quantization.
646 #define CODEC_FLAG_INTERLACED_DCT 0x00040000 ///< Use interlaced DCT.
647 #define CODEC_FLAG_LOW_DELAY      0x00080000 ///< Force low delay.
648 #define CODEC_FLAG_GLOBAL_HEADER  0x00400000 ///< Place global headers in extradata instead of every keyframe.
649 #define CODEC_FLAG_BITEXACT       0x00800000 ///< Use only bitexact stuff (except (I)DCT).
650 /* Fx : Flag for h263+ extra options */
651 #define CODEC_FLAG_AC_PRED        0x01000000 ///< H.263 advanced intra coding / MPEG-4 AC prediction
652 #define CODEC_FLAG_CBP_RD         0x04000000 ///< Use rate distortion optimization for cbp.
653 #define CODEC_FLAG_QP_RD          0x08000000 ///< Use rate distortion optimization for qp selectioon.
654 #define CODEC_FLAG_LOOP_FILTER    0x00000800 ///< loop filter
655 #define CODEC_FLAG_INTERLACED_ME  0x20000000 ///< interlaced motion estimation
656 #define CODEC_FLAG_CLOSED_GOP     0x80000000
657 #define CODEC_FLAG2_FAST          0x00000001 ///< Allow non spec compliant speedup tricks.
658 #define CODEC_FLAG2_STRICT_GOP    0x00000002 ///< Strictly enforce GOP size.
659 #define CODEC_FLAG2_NO_OUTPUT     0x00000004 ///< Skip bitstream encoding.
660 #define CODEC_FLAG2_LOCAL_HEADER  0x00000008 ///< Place global headers at every keyframe instead of in extradata.
661 #define CODEC_FLAG2_SKIP_RD       0x00004000 ///< RD optimal MB level residual skipping
662 #define CODEC_FLAG2_CHUNKS        0x00008000 ///< Input bitstream might be truncated at a packet boundaries instead of only at frame boundaries.
663 /**
664  * @defgroup deprecated_flags Deprecated codec flags
665  * Use corresponding private codec options instead.
666  * @{
667  */
668 #if FF_API_MPEGVIDEO_GLOBAL_OPTS
669 #define CODEC_FLAG_OBMC           0x00000001 ///< OBMC
670 #define CODEC_FLAG_H263P_AIV      0x00000008 ///< H.263 alternative inter VLC
671 #define CODEC_FLAG_PART   0x0080  ///< Use data partitioning.
672 #define CODEC_FLAG_ALT_SCAN       0x00100000 ///< Use alternate scan.
673 #define CODEC_FLAG_H263P_UMV      0x02000000 ///< unlimited motion vector
674 #define CODEC_FLAG_H263P_SLICE_STRUCT 0x10000000
675 #define CODEC_FLAG_SVCD_SCAN_OFFSET 0x40000000 ///< Will reserve space for SVCD scan offset user data.
676 #define CODEC_FLAG2_INTRA_VLC     0x00000800 ///< Use MPEG-2 intra VLC table.
677 #define CODEC_FLAG2_DROP_FRAME_TIMECODE 0x00002000 ///< timecode is in drop frame format.
678 #define CODEC_FLAG2_NON_LINEAR_QUANT 0x00010000 ///< Use MPEG-2 nonlinear quantizer.
679 #endif
680 #if FF_API_MJPEG_GLOBAL_OPTS
681 #define CODEC_FLAG_EXTERN_HUFF     0x1000   ///< Use external Huffman table (for MJPEG).
682 #endif
683 #if FF_API_X264_GLOBAL_OPTS
684 #define CODEC_FLAG2_BPYRAMID      0x00000010 ///< H.264 allow B-frames to be used as references.
685 #define CODEC_FLAG2_WPRED         0x00000020 ///< H.264 weighted biprediction for B-frames
686 #define CODEC_FLAG2_MIXED_REFS    0x00000040 ///< H.264 one reference per partition, as opposed to one reference per macroblock
687 #define CODEC_FLAG2_8X8DCT        0x00000080 ///< H.264 high profile 8x8 transform
688 #define CODEC_FLAG2_FASTPSKIP     0x00000100 ///< H.264 fast pskip
689 #define CODEC_FLAG2_AUD           0x00000200 ///< H.264 access unit delimiters
690 #define CODEC_FLAG2_BRDO          0x00000400 ///< B-frame rate-distortion optimization
691 #define CODEC_FLAG2_MBTREE        0x00040000 ///< Use macroblock tree ratecontrol (x264 only)
692 #define CODEC_FLAG2_PSY           0x00080000 ///< Use psycho visual optimizations.
693 #define CODEC_FLAG2_SSIM          0x00100000 ///< Compute SSIM during encoding, error[] values are undefined.
694 #define CODEC_FLAG2_INTRA_REFRESH 0x00200000 ///< Use periodic insertion of intra blocks instead of keyframes.
695 #endif
696 #if FF_API_SNOW_GLOBAL_OPTS
697 #define CODEC_FLAG2_MEMC_ONLY     0x00001000 ///< Only do ME/MC (I frames -> ref, P frame -> ME+MC).
698 #endif
699 #if FF_API_LAME_GLOBAL_OPTS
700 #define CODEC_FLAG2_BIT_RESERVOIR 0x00020000 ///< Use a bit reservoir when encoding if possible
701 #endif
702 /**
703  * @}
704  */
705 
706 /* Unsupported options :
707  *              Syntax Arithmetic coding (SAC)
708  *              Reference Picture Selection
709  *              Independent Segment Decoding */
710 /* /Fx */
711 /* codec capabilities */
712 
713 #define CODEC_CAP_DRAW_HORIZ_BAND 0x0001 ///< Decoder can use draw_horiz_band callback.
714 /**
715  * Codec uses get_buffer() for allocating buffers and supports custom allocators.
716  * If not set, it might not use get_buffer() at all or use operations that
717  * assume the buffer was allocated by avcodec_default_get_buffer.
718  */
719 #define CODEC_CAP_DR1             0x0002
720 #if FF_API_PARSE_FRAME
721 /* If 'parse_only' field is true, then avcodec_parse_frame() can be used. */
722 #define CODEC_CAP_PARSE_ONLY      0x0004
723 #endif
724 #define CODEC_CAP_TRUNCATED       0x0008
725 /* Codec can export data for HW decoding (XvMC). */
726 #define CODEC_CAP_HWACCEL         0x0010
727 /**
728  * Encoder or decoder requires flushing with NULL input at the end in order to
729  * give the complete and correct output.
730  *
731  * NOTE: If this flag is not set, the codec is guaranteed to never be fed with
732  *       with NULL data. The user can still send NULL data to the public encode
733  *       or decode function, but libavcodec will not pass it along to the codec
734  *       unless this flag is set.
735  *
736  * Decoders:
737  * The decoder has a non-zero delay and needs to be fed with avpkt->data=NULL,
738  * avpkt->size=0 at the end to get the delayed data until the decoder no longer
739  * returns frames.
740  *
741  * Encoders:
742  * The encoder needs to be fed with NULL data at the end of encoding until the
743  * encoder no longer returns data.
744  *
745  * NOTE: For encoders implementing the AVCodec.encode2() function, setting this
746  *       flag also means that the encoder must set the pts and duration for
747  *       each output packet. If this flag is not set, the pts and duration will
748  *       be determined by libavcodec from the input frame.
749  */
750 #define CODEC_CAP_DELAY           0x0020
751 /**
752  * Codec can be fed a final frame with a smaller size.
753  * This can be used to prevent truncation of the last audio samples.
754  */
755 #define CODEC_CAP_SMALL_LAST_FRAME 0x0040
756 /**
757  * Codec can export data for HW decoding (VDPAU).
758  */
759 #define CODEC_CAP_HWACCEL_VDPAU    0x0080
760 /**
761  * Codec can output multiple frames per AVPacket
762  * Normally demuxers return one frame at a time, demuxers which do not do
763  * are connected to a parser to split what they return into proper frames.
764  * This flag is reserved to the very rare category of codecs which have a
765  * bitstream that cannot be split into frames without timeconsuming
766  * operations like full decoding. Demuxers carring such bitstreams thus
767  * may return multiple frames in a packet. This has many disadvantages like
768  * prohibiting stream copy in many cases thus it should only be considered
769  * as a last resort.
770  */
771 #define CODEC_CAP_SUBFRAMES        0x0100
772 /**
773  * Codec is experimental and is thus avoided in favor of non experimental
774  * encoders
775  */
776 #define CODEC_CAP_EXPERIMENTAL     0x0200
777 /**
778  * Codec should fill in channel configuration and samplerate instead of container
779  */
780 #define CODEC_CAP_CHANNEL_CONF     0x0400
781 /**
782  * Codec is able to deal with negative linesizes
783  */
784 #define CODEC_CAP_NEG_LINESIZES    0x0800
785 /**
786  * Codec supports frame-level multithreading.
787  */
788 #define CODEC_CAP_FRAME_THREADS    0x1000
789 /**
790  * Codec supports slice-based (or partition-based) multithreading.
791  */
792 #define CODEC_CAP_SLICE_THREADS    0x2000
793 /**
794  * Codec supports changed parameters at any point.
795  */
796 #define CODEC_CAP_PARAM_CHANGE     0x4000
797 /**
798  * Codec supports avctx->thread_count == 0 (auto).
799  */
800 #define CODEC_CAP_AUTO_THREADS     0x8000
801 /**
802  * Audio encoder supports receiving a different number of samples in each call.
803  */
804 #define CODEC_CAP_VARIABLE_FRAME_SIZE 0x10000
805 
806 //The following defines may change, don't expect compatibility if you use them.
807 #define MB_TYPE_INTRA4x4   0x0001
808 #define MB_TYPE_INTRA16x16 0x0002 //FIXME H.264-specific
809 #define MB_TYPE_INTRA_PCM  0x0004 //FIXME H.264-specific
810 #define MB_TYPE_16x16      0x0008
811 #define MB_TYPE_16x8       0x0010
812 #define MB_TYPE_8x16       0x0020
813 #define MB_TYPE_8x8        0x0040
814 #define MB_TYPE_INTERLACED 0x0080
815 #define MB_TYPE_DIRECT2    0x0100 //FIXME
816 #define MB_TYPE_ACPRED     0x0200
817 #define MB_TYPE_GMC        0x0400
818 #define MB_TYPE_SKIP       0x0800
819 #define MB_TYPE_P0L0       0x1000
820 #define MB_TYPE_P1L0       0x2000
821 #define MB_TYPE_P0L1       0x4000
822 #define MB_TYPE_P1L1       0x8000
823 #define MB_TYPE_L0         (MB_TYPE_P0L0 | MB_TYPE_P1L0)
824 #define MB_TYPE_L1         (MB_TYPE_P0L1 | MB_TYPE_P1L1)
825 #define MB_TYPE_L0L1       (MB_TYPE_L0   | MB_TYPE_L1)
826 #define MB_TYPE_QUANT      0x00010000
827 #define MB_TYPE_CBP        0x00020000
828 //Note bits 24-31 are reserved for codec specific use (h264 ref0, mpeg1 0mv, ...)
829 
830 /**
831  * Pan Scan area.
832  * This specifies the area which should be displayed.
833  * Note there may be multiple such areas for one frame.
834  */
835 typedef struct AVPanScan{
836     /**
837      * id
838      * - encoding: Set by user.
839      * - decoding: Set by libavcodec.
840      */
841     int id;
842 
843     /**
844      * width and height in 1/16 pel
845      * - encoding: Set by user.
846      * - decoding: Set by libavcodec.
847      */
848     int width;
849     int height;
850 
851     /**
852      * position of the top left corner in 1/16 pel for up to 3 fields/frames
853      * - encoding: Set by user.
854      * - decoding: Set by libavcodec.
855      */
856     int16_t position[3][2];
857 }AVPanScan;
858 
859 #define FF_QSCALE_TYPE_MPEG1 0
860 #define FF_QSCALE_TYPE_MPEG2 1
861 #define FF_QSCALE_TYPE_H264  2
862 #define FF_QSCALE_TYPE_VP56  3
863 
864 #define FF_BUFFER_TYPE_INTERNAL 1
865 #define FF_BUFFER_TYPE_USER     2 ///< direct rendering buffers (image is (de)allocated by user)
866 #define FF_BUFFER_TYPE_SHARED   4 ///< Buffer from somewhere else; don't deallocate image (data/base), all other tables are not shared.
867 #define FF_BUFFER_TYPE_COPY     8 ///< Just a (modified) copy of some other buffer, don't deallocate anything.
868 
869 #if FF_API_OLD_FF_PICT_TYPES
870 /* DEPRECATED, directly use the AV_PICTURE_TYPE_* enum values */
871 #define FF_I_TYPE  AV_PICTURE_TYPE_I  ///< Intra
872 #define FF_P_TYPE  AV_PICTURE_TYPE_P  ///< Predicted
873 #define FF_B_TYPE  AV_PICTURE_TYPE_B  ///< Bi-dir predicted
874 #define FF_S_TYPE  AV_PICTURE_TYPE_S  ///< S(GMC)-VOP MPEG4
875 #define FF_SI_TYPE AV_PICTURE_TYPE_SI ///< Switching Intra
876 #define FF_SP_TYPE AV_PICTURE_TYPE_SP ///< Switching Predicted
877 #define FF_BI_TYPE AV_PICTURE_TYPE_BI
878 #endif
879 
880 #define FF_BUFFER_HINTS_VALID    0x01 // Buffer hints value is meaningful (if 0 ignore).
881 #define FF_BUFFER_HINTS_READABLE 0x02 // Codec will read from buffer.
882 #define FF_BUFFER_HINTS_PRESERVE 0x04 // User must not alter buffer content.
883 #define FF_BUFFER_HINTS_REUSABLE 0x08 // Codec will reuse the buffer (update).
884 
885 enum AVPacketSideDataType {
886     AV_PKT_DATA_PALETTE,
887     AV_PKT_DATA_NEW_EXTRADATA,
888     AV_PKT_DATA_PARAM_CHANGE,
889 };
890 
891 typedef struct AVPacket {
892     /**
893      * Presentation timestamp in AVStream->time_base units; the time at which
894      * the decompressed packet will be presented to the user.
895      * Can be AV_NOPTS_VALUE if it is not stored in the file.
896      * pts MUST be larger or equal to dts as presentation cannot happen before
897      * decompression, unless one wants to view hex dumps. Some formats misuse
898      * the terms dts and pts/cts to mean something different. Such timestamps
899      * must be converted to true pts/dts before they are stored in AVPacket.
900      */
901     int64_t pts;
902     /**
903      * Decompression timestamp in AVStream->time_base units; the time at which
904      * the packet is decompressed.
905      * Can be AV_NOPTS_VALUE if it is not stored in the file.
906      */
907     int64_t dts;
908     uint8_t *data;
909     int   size;
910     int   stream_index;
911     /**
912      * A combination of AV_PKT_FLAG values
913      */
914     int   flags;
915     /**
916      * Additional packet data that can be provided by the container.
917      * Packet can contain several types of side information.
918      */
919     struct {
920         uint8_t *data;
921         int      size;
922         enum AVPacketSideDataType type;
923     } *side_data;
924     int side_data_elems;
925 
926     /**
927      * Duration of this packet in AVStream->time_base units, 0 if unknown.
928      * Equals next_pts - this_pts in presentation order.
929      */
930     int   duration;
931     void  (*destruct)(struct AVPacket *);
932     void  *priv;
933     int64_t pos;                            ///< byte position in stream, -1 if unknown
934 
935     /**
936      * Time difference in AVStream->time_base units from the pts of this
937      * packet to the point at which the output from the decoder has converged
938      * independent from the availability of previous frames. That is, the
939      * frames are virtually identical no matter if decoding started from
940      * the very first frame or from this keyframe.
941      * Is AV_NOPTS_VALUE if unknown.
942      * This field is not the display duration of the current packet.
943      * This field has no meaning if the packet does not have AV_PKT_FLAG_KEY
944      * set.
945      *
946      * The purpose of this field is to allow seeking in streams that have no
947      * keyframes in the conventional sense. It corresponds to the
948      * recovery point SEI in H.264 and match_time_delta in NUT. It is also
949      * essential for some types of subtitle streams to ensure that all
950      * subtitles are correctly displayed after seeking.
951      */
952     int64_t convergence_duration;
953 } AVPacket;
954 #define AV_PKT_FLAG_KEY     0x0001 ///< The packet contains a keyframe
955 #define AV_PKT_FLAG_CORRUPT 0x0002 ///< The packet content is corrupted
956 
957 /**
958  * An AV_PKT_DATA_PARAM_CHANGE side data packet is laid out as follows:
959  * u32le param_flags
960  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT)
961  *     s32le channel_count
962  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT)
963  *     u64le channel_layout
964  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE)
965  *     s32le sample_rate
966  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS)
967  *     s32le width
968  *     s32le height
969  */
970 
971 enum AVSideDataParamChangeFlags {
972     AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT  = 0x0001,
973     AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT = 0x0002,
974     AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE    = 0x0004,
975     AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS     = 0x0008,
976 };
977 
978 /**
979  * Audio Video Frame.
980  * New fields can be added to the end of AVFRAME with minor version
981  * bumps. Removal, reordering and changes to existing fields require
982  * a major version bump.
983  * sizeof(AVFrame) must not be used outside libav*.
984  */
985 typedef struct AVFrame {
986 #if FF_API_DATA_POINTERS
987 #define AV_NUM_DATA_POINTERS 4
988 #else
989 #define AV_NUM_DATA_POINTERS 8
990 #endif
991     /**
992      * pointer to the picture/channel planes.
993      * This might be different from the first allocated byte
994      * - encoding: Set by user
995      * - decoding: set by AVCodecContext.get_buffer()
996      */
997     uint8_t *data[AV_NUM_DATA_POINTERS];
998 
999     /**
1000      * Size, in bytes, of the data for each picture/channel plane.
1001      *
1002      * For audio, only linesize[0] may be set. For planar audio, each channel
1003      * plane must be the same size.
1004      *
1005      * - encoding: Set by user (video only)
1006      * - decoding: set by AVCodecContext.get_buffer()
1007      */
1008     int linesize[AV_NUM_DATA_POINTERS];
1009 
1010     /**
1011      * pointer to the first allocated byte of the picture. Can be used in get_buffer/release_buffer.
1012      * This isn't used by libavcodec unless the default get/release_buffer() is used.
1013      * - encoding:
1014      * - decoding:
1015      */
1016     uint8_t *base[AV_NUM_DATA_POINTERS];
1017     /**
1018      * 1 -> keyframe, 0-> not
1019      * - encoding: Set by libavcodec.
1020      * - decoding: Set by libavcodec.
1021      */
1022     int key_frame;
1023 
1024     /**
1025      * Picture type of the frame, see ?_TYPE below.
1026      * - encoding: Set by libavcodec. for coded_picture (and set by user for input).
1027      * - decoding: Set by libavcodec.
1028      */
1029     enum AVPictureType pict_type;
1030 
1031     /**
1032      * presentation timestamp in time_base units (time when frame should be shown to user)
1033      * If AV_NOPTS_VALUE then frame_rate = 1/time_base will be assumed.
1034      * - encoding: MUST be set by user.
1035      * - decoding: Set by libavcodec.
1036      */
1037     int64_t pts;
1038 
1039     /**
1040      * picture number in bitstream order
1041      * - encoding: set by
1042      * - decoding: Set by libavcodec.
1043      */
1044     int coded_picture_number;
1045     /**
1046      * picture number in display order
1047      * - encoding: set by
1048      * - decoding: Set by libavcodec.
1049      */
1050     int display_picture_number;
1051 
1052     /**
1053      * quality (between 1 (good) and FF_LAMBDA_MAX (bad))
1054      * - encoding: Set by libavcodec. for coded_picture (and set by user for input).
1055      * - decoding: Set by libavcodec.
1056      */
1057     int quality;
1058 
1059 #if FF_API_AVFRAME_AGE
1060     /**
1061      * @deprecated unused
1062      */
1063     attribute_deprecated int age;
1064 #endif
1065 
1066     /**
1067      * is this picture used as reference
1068      * The values for this are the same as the MpegEncContext.picture_structure
1069      * variable, that is 1->top field, 2->bottom field, 3->frame/both fields.
1070      * Set to 4 for delayed, non-reference frames.
1071      * - encoding: unused
1072      * - decoding: Set by libavcodec. (before get_buffer() call)).
1073      */
1074     int reference;
1075 
1076     /**
1077      * QP table
1078      * - encoding: unused
1079      * - decoding: Set by libavcodec.
1080      */
1081     int8_t *qscale_table;
1082     /**
1083      * QP store stride
1084      * - encoding: unused
1085      * - decoding: Set by libavcodec.
1086      */
1087     int qstride;
1088 
1089     /**
1090      * mbskip_table[mb]>=1 if MB didn't change
1091      * stride= mb_width = (width+15)>>4
1092      * - encoding: unused
1093      * - decoding: Set by libavcodec.
1094      */
1095     uint8_t *mbskip_table;
1096 
1097     /**
1098      * motion vector table
1099      * @code
1100      * example:
1101      * int mv_sample_log2= 4 - motion_subsample_log2;
1102      * int mb_width= (width+15)>>4;
1103      * int mv_stride= (mb_width << mv_sample_log2) + 1;
1104      * motion_val[direction][x + y*mv_stride][0->mv_x, 1->mv_y];
1105      * @endcode
1106      * - encoding: Set by user.
1107      * - decoding: Set by libavcodec.
1108      */
1109     int16_t (*motion_val[2])[2];
1110 
1111     /**
1112      * macroblock type table
1113      * mb_type_base + mb_width + 2
1114      * - encoding: Set by user.
1115      * - decoding: Set by libavcodec.
1116      */
1117     uint32_t *mb_type;
1118 
1119     /**
1120      * log2 of the size of the block which a single vector in motion_val represents:
1121      * (4->16x16, 3->8x8, 2-> 4x4, 1-> 2x2)
1122      * - encoding: unused
1123      * - decoding: Set by libavcodec.
1124      */
1125     uint8_t motion_subsample_log2;
1126 
1127     /**
1128      * for some private data of the user
1129      * - encoding: unused
1130      * - decoding: Set by user.
1131      */
1132     void *opaque;
1133 
1134     /**
1135      * error
1136      * - encoding: Set by libavcodec. if flags&CODEC_FLAG_PSNR.
1137      * - decoding: unused
1138      */
1139     uint64_t error[AV_NUM_DATA_POINTERS];
1140 
1141     /**
1142      * type of the buffer (to keep track of who has to deallocate data[*])
1143      * - encoding: Set by the one who allocates it.
1144      * - decoding: Set by the one who allocates it.
1145      * Note: User allocated (direct rendering) & internal buffers cannot coexist currently.
1146      */
1147     int type;
1148 
1149     /**
1150      * When decoding, this signals how much the picture must be delayed.
1151      * extra_delay = repeat_pict / (2*fps)
1152      * - encoding: unused
1153      * - decoding: Set by libavcodec.
1154      */
1155     int repeat_pict;
1156 
1157     /**
1158      *
1159      */
1160     int qscale_type;
1161 
1162     /**
1163      * The content of the picture is interlaced.
1164      * - encoding: Set by user.
1165      * - decoding: Set by libavcodec. (default 0)
1166      */
1167     int interlaced_frame;
1168 
1169     /**
1170      * If the content is interlaced, is top field displayed first.
1171      * - encoding: Set by user.
1172      * - decoding: Set by libavcodec.
1173      */
1174     int top_field_first;
1175 
1176     /**
1177      * Pan scan.
1178      * - encoding: Set by user.
1179      * - decoding: Set by libavcodec.
1180      */
1181     AVPanScan *pan_scan;
1182 
1183     /**
1184      * Tell user application that palette has changed from previous frame.
1185      * - encoding: ??? (no palette-enabled encoder yet)
1186      * - decoding: Set by libavcodec. (default 0).
1187      */
1188     int palette_has_changed;
1189 
1190     /**
1191      * codec suggestion on buffer type if != 0
1192      * - encoding: unused
1193      * - decoding: Set by libavcodec. (before get_buffer() call)).
1194      */
1195     int buffer_hints;
1196 
1197     /**
1198      * DCT coefficients
1199      * - encoding: unused
1200      * - decoding: Set by libavcodec.
1201      */
1202     short *dct_coeff;
1203 
1204     /**
1205      * motion reference frame index
1206      * the order in which these are stored can depend on the codec.
1207      * - encoding: Set by user.
1208      * - decoding: Set by libavcodec.
1209      */
1210     int8_t *ref_index[2];
1211 
1212     /**
1213      * reordered opaque 64bit (generally an integer or a double precision float
1214      * PTS but can be anything).
1215      * The user sets AVCodecContext.reordered_opaque to represent the input at
1216      * that time,
1217      * the decoder reorders values as needed and sets AVFrame.reordered_opaque
1218      * to exactly one of the values provided by the user through AVCodecContext.reordered_opaque
1219      * @deprecated in favor of pkt_pts
1220      * - encoding: unused
1221      * - decoding: Read by user.
1222      */
1223     int64_t reordered_opaque;
1224 
1225     /**
1226      * hardware accelerator private data (Libav-allocated)
1227      * - encoding: unused
1228      * - decoding: Set by libavcodec
1229      */
1230     void *hwaccel_picture_private;
1231 
1232     /**
1233      * reordered pts from the last AVPacket that has been input into the decoder
1234      * - encoding: unused
1235      * - decoding: Read by user.
1236      */
1237     int64_t pkt_pts;
1238 
1239     /**
1240      * dts from the last AVPacket that has been input into the decoder
1241      * - encoding: unused
1242      * - decoding: Read by user.
1243      */
1244     int64_t pkt_dts;
1245 
1246     /**
1247      * the AVCodecContext which ff_thread_get_buffer() was last called on
1248      * - encoding: Set by libavcodec.
1249      * - decoding: Set by libavcodec.
1250      */
1251     struct AVCodecContext *owner;
1252 
1253     /**
1254      * used by multithreading to store frame-specific info
1255      * - encoding: Set by libavcodec.
1256      * - decoding: Set by libavcodec.
1257      */
1258     void *thread_opaque;
1259 
1260     /**
1261      * number of audio samples (per channel) described by this frame
1262      * - encoding: unused
1263      * - decoding: Set by libavcodec
1264      */
1265     int nb_samples;
1266 
1267     /**
1268      * pointers to the data planes/channels.
1269      *
1270      * For video, this should simply point to data[].
1271      *
1272      * For planar audio, each channel has a separate data pointer, and
1273      * linesize[0] contains the size of each channel buffer.
1274      * For packed audio, there is just one data pointer, and linesize[0]
1275      * contains the total size of the buffer for all channels.
1276      *
1277      * Note: Both data and extended_data will always be set by get_buffer(),
1278      * but for planar audio with more channels that can fit in data,
1279      * extended_data must be used by the decoder in order to access all
1280      * channels.
1281      *
1282      * encoding: unused
1283      * decoding: set by AVCodecContext.get_buffer()
1284      */
1285     uint8_t **extended_data;
1286 
1287     /**
1288      * sample aspect ratio for the video frame, 0/1 if unknown\unspecified
1289      * - encoding: unused
1290      * - decoding: Read by user.
1291      */
1292     AVRational sample_aspect_ratio;
1293 
1294     /**
1295      * width and height of the video frame
1296      * - encoding: unused
1297      * - decoding: Read by user.
1298      */
1299     int width, height;
1300 
1301     /**
1302      * format of the frame, -1 if unknown or unset
1303      * Values correspond to enum PixelFormat for video frames,
1304      * enum AVSampleFormat for audio)
1305      * - encoding: unused
1306      * - decoding: Read by user.
1307      */
1308     int format;
1309 } AVFrame;
1310 
1311 struct AVCodecInternal;
1312 
1313 enum AVFieldOrder {
1314     AV_FIELD_UNKNOWN,
1315     AV_FIELD_PROGRESSIVE,
1316     AV_FIELD_TT,          //< Top coded_first, top displayed first
1317     AV_FIELD_BB,          //< Bottom coded first, bottom displayed first
1318     AV_FIELD_TB,          //< Top coded first, bottom displayed first
1319     AV_FIELD_BT,          //< Bottom coded first, top displayed first
1320 };
1321 
1322 /**
1323  * main external API structure.
1324  * New fields can be added to the end with minor version bumps.
1325  * Removal, reordering and changes to existing fields require a major
1326  * version bump.
1327  * sizeof(AVCodecContext) must not be used outside libav*.
1328  */
1329 typedef struct AVCodecContext {
1330     /**
1331      * information on struct for av_log
1332      * - set by avcodec_alloc_context3
1333      */
1334     const AVClass *av_class;
1335     /**
1336      * the average bitrate
1337      * - encoding: Set by user; unused for constant quantizer encoding.
1338      * - decoding: Set by libavcodec. 0 or some bitrate if this info is available in the stream.
1339      */
1340     int bit_rate;
1341 
1342     /**
1343      * number of bits the bitstream is allowed to diverge from the reference.
1344      *           the reference can be CBR (for CBR pass1) or VBR (for pass2)
1345      * - encoding: Set by user; unused for constant quantizer encoding.
1346      * - decoding: unused
1347      */
1348     int bit_rate_tolerance;
1349 
1350     /**
1351      * CODEC_FLAG_*.
1352      * - encoding: Set by user.
1353      * - decoding: Set by user.
1354      */
1355     int flags;
1356 
1357     /**
1358      * Some codecs need additional format info. It is stored here.
1359      * If any muxer uses this then ALL demuxers/parsers AND encoders for the
1360      * specific codec MUST set it correctly otherwise stream copy breaks.
1361      * In general use of this field by muxers is not recommended.
1362      * - encoding: Set by libavcodec.
1363      * - decoding: Set by libavcodec. (FIXME: Is this OK?)
1364      */
1365     int sub_id;
1366 
1367     /**
1368      * Motion estimation algorithm used for video coding.
1369      * 1 (zero), 2 (full), 3 (log), 4 (phods), 5 (epzs), 6 (x1), 7 (hex),
1370      * 8 (umh), 9 (iter), 10 (tesa) [7, 8, 10 are x264 specific, 9 is snow specific]
1371      * - encoding: MUST be set by user.
1372      * - decoding: unused
1373      */
1374     int me_method;
1375 
1376     /**
1377      * some codecs need / can use extradata like Huffman tables.
1378      * mjpeg: Huffman tables
1379      * rv10: additional flags
1380      * mpeg4: global headers (they can be in the bitstream or here)
1381      * The allocated memory should be FF_INPUT_BUFFER_PADDING_SIZE bytes larger
1382      * than extradata_size to avoid prolems if it is read with the bitstream reader.
1383      * The bytewise contents of extradata must not depend on the architecture or CPU endianness.
1384      * - encoding: Set/allocated/freed by libavcodec.
1385      * - decoding: Set/allocated/freed by user.
1386      */
1387     uint8_t *extradata;
1388     int extradata_size;
1389 
1390     /**
1391      * This is the fundamental unit of time (in seconds) in terms
1392      * of which frame timestamps are represented. For fixed-fps content,
1393      * timebase should be 1/framerate and timestamp increments should be
1394      * identically 1.
1395      * - encoding: MUST be set by user.
1396      * - decoding: Set by libavcodec.
1397      */
1398     AVRational time_base;
1399 
1400     /* video only */
1401     /**
1402      * picture width / height.
1403      * - encoding: MUST be set by user.
1404      * - decoding: Set by libavcodec.
1405      * Note: For compatibility it is possible to set this instead of
1406      * coded_width/height before decoding.
1407      */
1408     int width, height;
1409 
1410 #define FF_ASPECT_EXTENDED 15
1411 
1412     /**
1413      * the number of pictures in a group of pictures, or 0 for intra_only
1414      * - encoding: Set by user.
1415      * - decoding: unused
1416      */
1417     int gop_size;
1418 
1419     /**
1420      * Pixel format, see PIX_FMT_xxx.
1421      * May be set by the demuxer if known from headers.
1422      * May be overriden by the decoder if it knows better.
1423      * - encoding: Set by user.
1424      * - decoding: Set by user if known, overridden by libavcodec if known
1425      */
1426     enum PixelFormat pix_fmt;
1427 
1428     /**
1429      * If non NULL, 'draw_horiz_band' is called by the libavcodec
1430      * decoder to draw a horizontal band. It improves cache usage. Not
1431      * all codecs can do that. You must check the codec capabilities
1432      * beforehand.
1433      * When multithreading is used, it may be called from multiple threads
1434      * at the same time; threads might draw different parts of the same AVFrame,
1435      * or multiple AVFrames, and there is no guarantee that slices will be drawn
1436      * in order.
1437      * The function is also used by hardware acceleration APIs.
1438      * It is called at least once during frame decoding to pass
1439      * the data needed for hardware render.
1440      * In that mode instead of pixel data, AVFrame points to
1441      * a structure specific to the acceleration API. The application
1442      * reads the structure and can change some fields to indicate progress
1443      * or mark state.
1444      * - encoding: unused
1445      * - decoding: Set by user.
1446      * @param height the height of the slice
1447      * @param y the y position of the slice
1448      * @param type 1->top field, 2->bottom field, 3->frame
1449      * @param offset offset into the AVFrame.data from which the slice should be read
1450      */
1451     void (*draw_horiz_band)(struct AVCodecContext *s,
1452                             const AVFrame *src, int offset[AV_NUM_DATA_POINTERS],
1453                             int y, int type, int height);
1454 
1455     /* audio only */
1456     int sample_rate; ///< samples per second
1457     int channels;    ///< number of audio channels
1458 
1459     /**
1460      * audio sample format
1461      * - encoding: Set by user.
1462      * - decoding: Set by libavcodec.
1463      */
1464     enum AVSampleFormat sample_fmt;  ///< sample format
1465 
1466     /* The following data should not be initialized. */
1467     /**
1468      * Samples per packet, initialized when calling 'init'.
1469      */
1470     int frame_size;
1471     int frame_number;   ///< audio or video frame number
1472 
1473     /**
1474      * Number of frames the decoded output will be delayed relative to
1475      * the encoded input.
1476      * - encoding: Set by libavcodec.
1477      * - decoding: unused
1478      */
1479     int delay;
1480 
1481     /* - encoding parameters */
1482     float qcompress;  ///< amount of qscale change between easy & hard scenes (0.0-1.0)
1483     float qblur;      ///< amount of qscale smoothing over time (0.0-1.0)
1484 
1485     /**
1486      * minimum quantizer
1487      * - encoding: Set by user.
1488      * - decoding: unused
1489      */
1490     int qmin;
1491 
1492     /**
1493      * maximum quantizer
1494      * - encoding: Set by user.
1495      * - decoding: unused
1496      */
1497     int qmax;
1498 
1499     /**
1500      * maximum quantizer difference between frames
1501      * - encoding: Set by user.
1502      * - decoding: unused
1503      */
1504     int max_qdiff;
1505 
1506     /**
1507      * maximum number of B-frames between non-B-frames
1508      * Note: The output will be delayed by max_b_frames+1 relative to the input.
1509      * - encoding: Set by user.
1510      * - decoding: unused
1511      */
1512     int max_b_frames;
1513 
1514     /**
1515      * qscale factor between IP and B-frames
1516      * If > 0 then the last P-frame quantizer will be used (q= lastp_q*factor+offset).
1517      * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1518      * - encoding: Set by user.
1519      * - decoding: unused
1520      */
1521     float b_quant_factor;
1522 
1523     /** obsolete FIXME remove */
1524     int rc_strategy;
1525 #define FF_RC_STRATEGY_XVID 1
1526 
1527     int b_frame_strategy;
1528 
1529     struct AVCodec *codec;
1530 
1531     void *priv_data;
1532 
1533     int rtp_payload_size;   /* The size of the RTP payload: the coder will  */
1534                             /* do its best to deliver a chunk with size     */
1535                             /* below rtp_payload_size, the chunk will start */
1536                             /* with a start code on some codecs like H.263. */
1537                             /* This doesn't take account of any particular  */
1538                             /* headers inside the transmitted RTP payload.  */
1539 
1540 
1541     /* The RTP callback: This function is called    */
1542     /* every time the encoder has a packet to send. */
1543     /* It depends on the encoder if the data starts */
1544     /* with a Start Code (it should). H.263 does.   */
1545     /* mb_nb contains the number of macroblocks     */
1546     /* encoded in the RTP payload.                  */
1547     void (*rtp_callback)(struct AVCodecContext *avctx, void *data, int size, int mb_nb);
1548 
1549     /* statistics, used for 2-pass encoding */
1550     int mv_bits;
1551     int header_bits;
1552     int i_tex_bits;
1553     int p_tex_bits;
1554     int i_count;
1555     int p_count;
1556     int skip_count;
1557     int misc_bits;
1558 
1559     /**
1560      * number of bits used for the previously encoded frame
1561      * - encoding: Set by libavcodec.
1562      * - decoding: unused
1563      */
1564     int frame_bits;
1565 
1566     /**
1567      * Private data of the user, can be used to carry app specific stuff.
1568      * - encoding: Set by user.
1569      * - decoding: Set by user.
1570      */
1571     void *opaque;
1572 
1573     char codec_name[32];
1574     enum AVMediaType codec_type; /* see AVMEDIA_TYPE_xxx */
1575     enum CodecID codec_id; /* see CODEC_ID_xxx */
1576 
1577     /**
1578      * fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
1579      * This is used to work around some encoder bugs.
1580      * A demuxer should set this to what is stored in the field used to identify the codec.
1581      * If there are multiple such fields in a container then the demuxer should choose the one
1582      * which maximizes the information about the used codec.
1583      * If the codec tag field in a container is larger than 32 bits then the demuxer should
1584      * remap the longer ID to 32 bits with a table or other structure. Alternatively a new
1585      * extra_codec_tag + size could be added but for this a clear advantage must be demonstrated
1586      * first.
1587      * - encoding: Set by user, if not then the default based on codec_id will be used.
1588      * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
1589      */
1590     unsigned int codec_tag;
1591 
1592     /**
1593      * Work around bugs in encoders which sometimes cannot be detected automatically.
1594      * - encoding: Set by user
1595      * - decoding: Set by user
1596      */
1597     int workaround_bugs;
1598 #define FF_BUG_AUTODETECT       1  ///< autodetection
1599 #define FF_BUG_OLD_MSMPEG4      2
1600 #define FF_BUG_XVID_ILACE       4
1601 #define FF_BUG_UMP4             8
1602 #define FF_BUG_NO_PADDING       16
1603 #define FF_BUG_AMV              32
1604 #define FF_BUG_AC_VLC           0  ///< Will be removed, libavcodec can now handle these non-compliant files by default.
1605 #define FF_BUG_QPEL_CHROMA      64
1606 #define FF_BUG_STD_QPEL         128
1607 #define FF_BUG_QPEL_CHROMA2     256
1608 #define FF_BUG_DIRECT_BLOCKSIZE 512
1609 #define FF_BUG_EDGE             1024
1610 #define FF_BUG_HPEL_CHROMA      2048
1611 #define FF_BUG_DC_CLIP          4096
1612 #define FF_BUG_MS               8192 ///< Work around various bugs in Microsoft's broken decoders.
1613 #define FF_BUG_TRUNCATED       16384
1614 //#define FF_BUG_FAKE_SCALABILITY 16 //Autodetection should work 100%.
1615 
1616     /**
1617      * luma single coefficient elimination threshold
1618      * - encoding: Set by user.
1619      * - decoding: unused
1620      */
1621     int luma_elim_threshold;
1622 
1623     /**
1624      * chroma single coeff elimination threshold
1625      * - encoding: Set by user.
1626      * - decoding: unused
1627      */
1628     int chroma_elim_threshold;
1629 
1630     /**
1631      * strictly follow the standard (MPEG4, ...).
1632      * - encoding: Set by user.
1633      * - decoding: Set by user.
1634      * Setting this to STRICT or higher means the encoder and decoder will
1635      * generally do stupid things, whereas setting it to unofficial or lower
1636      * will mean the encoder might produce output that is not supported by all
1637      * spec-compliant decoders. Decoders don't differentiate between normal,
1638      * unofficial and experimental (that is, they always try to decode things
1639      * when they can) unless they are explicitly asked to behave stupidly
1640      * (=strictly conform to the specs)
1641      */
1642     int strict_std_compliance;
1643 #define FF_COMPLIANCE_VERY_STRICT   2 ///< Strictly conform to an older more strict version of the spec or reference software.
1644 #define FF_COMPLIANCE_STRICT        1 ///< Strictly conform to all the things in the spec no matter what consequences.
1645 #define FF_COMPLIANCE_NORMAL        0
1646 #define FF_COMPLIANCE_UNOFFICIAL   -1 ///< Allow unofficial extensions
1647 #define FF_COMPLIANCE_EXPERIMENTAL -2 ///< Allow nonstandardized experimental things.
1648 
1649     /**
1650      * qscale offset between IP and B-frames
1651      * - encoding: Set by user.
1652      * - decoding: unused
1653      */
1654     float b_quant_offset;
1655 
1656 #if FF_API_ER
1657     /**
1658      * Error recognition; higher values will detect more errors but may
1659      * misdetect some more or less valid parts as errors.
1660      * - encoding: unused
1661      * - decoding: Set by user.
1662      */
1663     attribute_deprecated int error_recognition;
1664 #define FF_ER_CAREFUL         1
1665 #define FF_ER_COMPLIANT       2
1666 #define FF_ER_AGGRESSIVE      3
1667 #define FF_ER_VERY_AGGRESSIVE 4
1668 #define FF_ER_EXPLODE         5
1669 #endif /* FF_API_ER */
1670 
1671     /**
1672      * Called at the beginning of each frame to get a buffer for it.
1673      *
1674      * The function will set AVFrame.data[], AVFrame.linesize[].
1675      * AVFrame.extended_data[] must also be set, but it should be the same as
1676      * AVFrame.data[] except for planar audio with more channels than can fit
1677      * in AVFrame.data[]. In that case, AVFrame.data[] shall still contain as
1678      * many data pointers as it can hold.
1679      *
1680      * if CODEC_CAP_DR1 is not set then get_buffer() must call
1681      * avcodec_default_get_buffer() instead of providing buffers allocated by
1682      * some other means.
1683      *
1684      * AVFrame.data[] should be 32- or 16-byte-aligned unless the CPU doesn't
1685      * need it. avcodec_default_get_buffer() aligns the output buffer properly,
1686      * but if get_buffer() is overridden then alignment considerations should
1687      * be taken into account.
1688      *
1689      * @see avcodec_default_get_buffer()
1690      *
1691      * Video:
1692      *
1693      * If pic.reference is set then the frame will be read later by libavcodec.
1694      * avcodec_align_dimensions2() should be used to find the required width and
1695      * height, as they normally need to be rounded up to the next multiple of 16.
1696      *
1697      * If frame multithreading is used and thread_safe_callbacks is set,
1698      * it may be called from a different thread, but not from more than one at
1699      * once. Does not need to be reentrant.
1700      *
1701      * @see release_buffer(), reget_buffer()
1702      * @see avcodec_align_dimensions2()
1703      *
1704      * Audio:
1705      *
1706      * Decoders request a buffer of a particular size by setting
1707      * AVFrame.nb_samples prior to calling get_buffer(). The decoder may,
1708      * however, utilize only part of the buffer by setting AVFrame.nb_samples
1709      * to a smaller value in the output frame.
1710      *
1711      * Decoders cannot use the buffer after returning from
1712      * avcodec_decode_audio4(), so they will not call release_buffer(), as it
1713      * is assumed to be released immediately upon return.
1714      *
1715      * As a convenience, av_samples_get_buffer_size() and
1716      * av_samples_fill_arrays() in libavutil may be used by custom get_buffer()
1717      * functions to find the required data size and to fill data pointers and
1718      * linesize. In AVFrame.linesize, only linesize[0] may be set for audio
1719      * since all planes must be the same size.
1720      *
1721      * @see av_samples_get_buffer_size(), av_samples_fill_arrays()
1722      *
1723      * - encoding: unused
1724      * - decoding: Set by libavcodec, user can override.
1725      */
1726     int (*get_buffer)(struct AVCodecContext *c, AVFrame *pic);
1727 
1728     /**
1729      * Called to release buffers which were allocated with get_buffer.
1730      * A released buffer can be reused in get_buffer().
1731      * pic.data[*] must be set to NULL.
1732      * May be called from a different thread if frame multithreading is used,
1733      * but not by more than one thread at once, so does not need to be reentrant.
1734      * - encoding: unused
1735      * - decoding: Set by libavcodec, user can override.
1736      */
1737     void (*release_buffer)(struct AVCodecContext *c, AVFrame *pic);
1738 
1739     /**
1740      * Size of the frame reordering buffer in the decoder.
1741      * For MPEG-2 it is 1 IPB or 0 low delay IP.
1742      * - encoding: Set by libavcodec.
1743      * - decoding: Set by libavcodec.
1744      */
1745     int has_b_frames;
1746 
1747     /**
1748      * number of bytes per packet if constant and known or 0
1749      * Used by some WAV based audio codecs.
1750      */
1751     int block_align;
1752 
1753 #if FF_API_PARSE_FRAME
1754     /**
1755      * If true, only parsing is done. The frame data is returned.
1756      * Only MPEG audio decoders support this now.
1757      * - encoding: unused
1758      * - decoding: Set by user
1759      */
1760     attribute_deprecated int parse_only;
1761 #endif
1762 
1763     /**
1764      * 0-> h263 quant 1-> mpeg quant
1765      * - encoding: Set by user.
1766      * - decoding: unused
1767      */
1768     int mpeg_quant;
1769 
1770     /**
1771      * pass1 encoding statistics output buffer
1772      * - encoding: Set by libavcodec.
1773      * - decoding: unused
1774      */
1775     char *stats_out;
1776 
1777     /**
1778      * pass2 encoding statistics input buffer
1779      * Concatenated stuff from stats_out of pass1 should be placed here.
1780      * - encoding: Allocated/set/freed by user.
1781      * - decoding: unused
1782      */
1783     char *stats_in;
1784 
1785     /**
1786      * ratecontrol qmin qmax limiting method
1787      * 0-> clipping, 1-> use a nice continous function to limit qscale wthin qmin/qmax.
1788      * - encoding: Set by user.
1789      * - decoding: unused
1790      */
1791     float rc_qsquish;
1792 
1793     float rc_qmod_amp;
1794     int rc_qmod_freq;
1795 
1796     /**
1797      * ratecontrol override, see RcOverride
1798      * - encoding: Allocated/set/freed by user.
1799      * - decoding: unused
1800      */
1801     RcOverride *rc_override;
1802     int rc_override_count;
1803 
1804     /**
1805      * rate control equation
1806      * - encoding: Set by user
1807      * - decoding: unused
1808      */
1809     const char *rc_eq;
1810 
1811     /**
1812      * maximum bitrate
1813      * - encoding: Set by user.
1814      * - decoding: unused
1815      */
1816     int rc_max_rate;
1817 
1818     /**
1819      * minimum bitrate
1820      * - encoding: Set by user.
1821      * - decoding: unused
1822      */
1823     int rc_min_rate;
1824 
1825     /**
1826      * decoder bitstream buffer size
1827      * - encoding: Set by user.
1828      * - decoding: unused
1829      */
1830     int rc_buffer_size;
1831     float rc_buffer_aggressivity;
1832 
1833     /**
1834      * qscale factor between P and I-frames
1835      * If > 0 then the last p frame quantizer will be used (q= lastp_q*factor+offset).
1836      * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1837      * - encoding: Set by user.
1838      * - decoding: unused
1839      */
1840     float i_quant_factor;
1841 
1842     /**
1843      * qscale offset between P and I-frames
1844      * - encoding: Set by user.
1845      * - decoding: unused
1846      */
1847     float i_quant_offset;
1848 
1849     /**
1850      * initial complexity for pass1 ratecontrol
1851      * - encoding: Set by user.
1852      * - decoding: unused
1853      */
1854     float rc_initial_cplx;
1855 
1856     /**
1857      * DCT algorithm, see FF_DCT_* below
1858      * - encoding: Set by user.
1859      * - decoding: unused
1860      */
1861     int dct_algo;
1862 #define FF_DCT_AUTO    0
1863 #define FF_DCT_FASTINT 1
1864 #define FF_DCT_INT     2
1865 #define FF_DCT_MMX     3
1866 #define FF_DCT_MLIB    4
1867 #define FF_DCT_ALTIVEC 5
1868 #define FF_DCT_FAAN    6
1869 
1870     /**
1871      * luminance masking (0-> disabled)
1872      * - encoding: Set by user.
1873      * - decoding: unused
1874      */
1875     float lumi_masking;
1876 
1877     /**
1878      * temporary complexity masking (0-> disabled)
1879      * - encoding: Set by user.
1880      * - decoding: unused
1881      */
1882     float temporal_cplx_masking;
1883 
1884     /**
1885      * spatial complexity masking (0-> disabled)
1886      * - encoding: Set by user.
1887      * - decoding: unused
1888      */
1889     float spatial_cplx_masking;
1890 
1891     /**
1892      * p block masking (0-> disabled)
1893      * - encoding: Set by user.
1894      * - decoding: unused
1895      */
1896     float p_masking;
1897 
1898     /**
1899      * darkness masking (0-> disabled)
1900      * - encoding: Set by user.
1901      * - decoding: unused
1902      */
1903     float dark_masking;
1904 
1905     /**
1906      * IDCT algorithm, see FF_IDCT_* below.
1907      * - encoding: Set by user.
1908      * - decoding: Set by user.
1909      */
1910     int idct_algo;
1911 #define FF_IDCT_AUTO          0
1912 #define FF_IDCT_INT           1
1913 #define FF_IDCT_SIMPLE        2
1914 #define FF_IDCT_SIMPLEMMX     3
1915 #define FF_IDCT_LIBMPEG2MMX   4
1916 #define FF_IDCT_PS2           5
1917 #define FF_IDCT_MLIB          6
1918 #define FF_IDCT_ARM           7
1919 #define FF_IDCT_ALTIVEC       8
1920 #define FF_IDCT_SH4           9
1921 #define FF_IDCT_SIMPLEARM     10
1922 #define FF_IDCT_H264          11
1923 #define FF_IDCT_VP3           12
1924 #define FF_IDCT_IPP           13
1925 #define FF_IDCT_XVIDMMX       14
1926 #define FF_IDCT_CAVS          15
1927 #define FF_IDCT_SIMPLEARMV5TE 16
1928 #define FF_IDCT_SIMPLEARMV6   17
1929 #define FF_IDCT_SIMPLEVIS     18
1930 #define FF_IDCT_WMV2          19
1931 #define FF_IDCT_FAAN          20
1932 #define FF_IDCT_EA            21
1933 #define FF_IDCT_SIMPLENEON    22
1934 #define FF_IDCT_SIMPLEALPHA   23
1935 #define FF_IDCT_BINK          24
1936 
1937     /**
1938      * slice count
1939      * - encoding: Set by libavcodec.
1940      * - decoding: Set by user (or 0).
1941      */
1942     int slice_count;
1943     /**
1944      * slice offsets in the frame in bytes
1945      * - encoding: Set/allocated by libavcodec.
1946      * - decoding: Set/allocated by user (or NULL).
1947      */
1948     int *slice_offset;
1949 
1950     /**
1951      * error concealment flags
1952      * - encoding: unused
1953      * - decoding: Set by user.
1954      */
1955     int error_concealment;
1956 #define FF_EC_GUESS_MVS   1
1957 #define FF_EC_DEBLOCK     2
1958 
1959     /**
1960      * dsp_mask could be add used to disable unwanted CPU features
1961      * CPU features (i.e. MMX, SSE. ...)
1962      *
1963      * With the FORCE flag you may instead enable given CPU features.
1964      * (Dangerous: Usable in case of misdetection, improper usage however will
1965      * result into program crash.)
1966      */
1967     unsigned dsp_mask;
1968 
1969     /**
1970      * bits per sample/pixel from the demuxer (needed for huffyuv).
1971      * - encoding: Set by libavcodec.
1972      * - decoding: Set by user.
1973      */
1974      int bits_per_coded_sample;
1975 
1976     /**
1977      * prediction method (needed for huffyuv)
1978      * - encoding: Set by user.
1979      * - decoding: unused
1980      */
1981      int prediction_method;
1982 #define FF_PRED_LEFT   0
1983 #define FF_PRED_PLANE  1
1984 #define FF_PRED_MEDIAN 2
1985 
1986     /**
1987      * sample aspect ratio (0 if unknown)
1988      * That is the width of a pixel divided by the height of the pixel.
1989      * Numerator and denominator must be relatively prime and smaller than 256 for some video standards.
1990      * - encoding: Set by user.
1991      * - decoding: Set by libavcodec.
1992      */
1993     AVRational sample_aspect_ratio;
1994 
1995     /**
1996      * the picture in the bitstream
1997      * - encoding: Set by libavcodec.
1998      * - decoding: Set by libavcodec.
1999      */
2000     AVFrame *coded_frame;
2001 
2002     /**
2003      * debug
2004      * - encoding: Set by user.
2005      * - decoding: Set by user.
2006      */
2007     int debug;
2008 #define FF_DEBUG_PICT_INFO   1
2009 #define FF_DEBUG_RC          2
2010 #define FF_DEBUG_BITSTREAM   4
2011 #define FF_DEBUG_MB_TYPE     8
2012 #define FF_DEBUG_QP          16
2013 #define FF_DEBUG_MV          32
2014 #define FF_DEBUG_DCT_COEFF   0x00000040
2015 #define FF_DEBUG_SKIP        0x00000080
2016 #define FF_DEBUG_STARTCODE   0x00000100
2017 #define FF_DEBUG_PTS         0x00000200
2018 #define FF_DEBUG_ER          0x00000400
2019 #define FF_DEBUG_MMCO        0x00000800
2020 #define FF_DEBUG_BUGS        0x00001000
2021 #define FF_DEBUG_VIS_QP      0x00002000
2022 #define FF_DEBUG_VIS_MB_TYPE 0x00004000
2023 #define FF_DEBUG_BUFFERS     0x00008000
2024 #define FF_DEBUG_THREADS     0x00010000
2025 
2026     /**
2027      * debug
2028      * - encoding: Set by user.
2029      * - decoding: Set by user.
2030      */
2031     int debug_mv;
2032 #define FF_DEBUG_VIS_MV_P_FOR  0x00000001 //visualize forward predicted MVs of P frames
2033 #define FF_DEBUG_VIS_MV_B_FOR  0x00000002 //visualize forward predicted MVs of B frames
2034 #define FF_DEBUG_VIS_MV_B_BACK 0x00000004 //visualize backward predicted MVs of B frames
2035 
2036     /**
2037      * error
2038      * - encoding: Set by libavcodec if flags&CODEC_FLAG_PSNR.
2039      * - decoding: unused
2040      */
2041     uint64_t error[AV_NUM_DATA_POINTERS];
2042 
2043     /**
2044      * motion estimation comparison function
2045      * - encoding: Set by user.
2046      * - decoding: unused
2047      */
2048     int me_cmp;
2049     /**
2050      * subpixel motion estimation comparison function
2051      * - encoding: Set by user.
2052      * - decoding: unused
2053      */
2054     int me_sub_cmp;
2055     /**
2056      * macroblock comparison function (not supported yet)
2057      * - encoding: Set by user.
2058      * - decoding: unused
2059      */
2060     int mb_cmp;
2061     /**
2062      * interlaced DCT comparison function
2063      * - encoding: Set by user.
2064      * - decoding: unused
2065      */
2066     int ildct_cmp;
2067 #define FF_CMP_SAD    0
2068 #define FF_CMP_SSE    1
2069 #define FF_CMP_SATD   2
2070 #define FF_CMP_DCT    3
2071 #define FF_CMP_PSNR   4
2072 #define FF_CMP_BIT    5
2073 #define FF_CMP_RD     6
2074 #define FF_CMP_ZERO   7
2075 #define FF_CMP_VSAD   8
2076 #define FF_CMP_VSSE   9
2077 #define FF_CMP_NSSE   10
2078 #define FF_CMP_W53    11
2079 #define FF_CMP_W97    12
2080 #define FF_CMP_DCTMAX 13
2081 #define FF_CMP_DCT264 14
2082 #define FF_CMP_CHROMA 256
2083 
2084     /**
2085      * ME diamond size & shape
2086      * - encoding: Set by user.
2087      * - decoding: unused
2088      */
2089     int dia_size;
2090 
2091     /**
2092      * amount of previous MV predictors (2a+1 x 2a+1 square)
2093      * - encoding: Set by user.
2094      * - decoding: unused
2095      */
2096     int last_predictor_count;
2097 
2098     /**
2099      * prepass for motion estimation
2100      * - encoding: Set by user.
2101      * - decoding: unused
2102      */
2103     int pre_me;
2104 
2105     /**
2106      * motion estimation prepass comparison function
2107      * - encoding: Set by user.
2108      * - decoding: unused
2109      */
2110     int me_pre_cmp;
2111 
2112     /**
2113      * ME prepass diamond size & shape
2114      * - encoding: Set by user.
2115      * - decoding: unused
2116      */
2117     int pre_dia_size;
2118 
2119     /**
2120      * subpel ME quality
2121      * - encoding: Set by user.
2122      * - decoding: unused
2123      */
2124     int me_subpel_quality;
2125 
2126     /**
2127      * callback to negotiate the pixelFormat
2128      * @param fmt is the list of formats which are supported by the codec,
2129      * it is terminated by -1 as 0 is a valid format, the formats are ordered by quality.
2130      * The first is always the native one.
2131      * @return the chosen format
2132      * - encoding: unused
2133      * - decoding: Set by user, if not set the native format will be chosen.
2134      */
2135     enum PixelFormat (*get_format)(struct AVCodecContext *s, const enum PixelFormat * fmt);
2136 
2137     /**
2138      * DTG active format information (additional aspect ratio
2139      * information only used in DVB MPEG-2 transport streams)
2140      * 0 if not set.
2141      *
2142      * - encoding: unused
2143      * - decoding: Set by decoder.
2144      */
2145     int dtg_active_format;
2146 #define FF_DTG_AFD_SAME         8
2147 #define FF_DTG_AFD_4_3          9
2148 #define FF_DTG_AFD_16_9         10
2149 #define FF_DTG_AFD_14_9         11
2150 #define FF_DTG_AFD_4_3_SP_14_9  13
2151 #define FF_DTG_AFD_16_9_SP_14_9 14
2152 #define FF_DTG_AFD_SP_4_3       15
2153 
2154     /**
2155      * maximum motion estimation search range in subpel units
2156      * If 0 then no limit.
2157      *
2158      * - encoding: Set by user.
2159      * - decoding: unused
2160      */
2161     int me_range;
2162 
2163     /**
2164      * intra quantizer bias
2165      * - encoding: Set by user.
2166      * - decoding: unused
2167      */
2168     int intra_quant_bias;
2169 #define FF_DEFAULT_QUANT_BIAS 999999
2170 
2171     /**
2172      * inter quantizer bias
2173      * - encoding: Set by user.
2174      * - decoding: unused
2175      */
2176     int inter_quant_bias;
2177 
2178     /**
2179      * color table ID
2180      * - encoding: unused
2181      * - decoding: Which clrtable should be used for 8bit RGB images.
2182      *             Tables have to be stored somewhere. FIXME
2183      */
2184     int color_table_id;
2185 
2186 #if FF_API_INTERNAL_CONTEXT
2187     /**
2188      * internal_buffer count
2189      * Don't touch, used by libavcodec default_get_buffer().
2190      * @deprecated this field was moved to an internal context
2191      */
2192     attribute_deprecated int internal_buffer_count;
2193 
2194     /**
2195      * internal_buffers
2196      * Don't touch, used by libavcodec default_get_buffer().
2197      * @deprecated this field was moved to an internal context
2198      */
2199     attribute_deprecated void *internal_buffer;
2200 #endif
2201 
2202     /**
2203      * Global quality for codecs which cannot change it per frame.
2204      * This should be proportional to MPEG-1/2/4 qscale.
2205      * - encoding: Set by user.
2206      * - decoding: unused
2207      */
2208     int global_quality;
2209 
2210 #define FF_CODER_TYPE_VLC       0
2211 #define FF_CODER_TYPE_AC        1
2212 #define FF_CODER_TYPE_RAW       2
2213 #define FF_CODER_TYPE_RLE       3
2214 #define FF_CODER_TYPE_DEFLATE   4
2215     /**
2216      * coder type
2217      * - encoding: Set by user.
2218      * - decoding: unused
2219      */
2220     int coder_type;
2221 
2222     /**
2223      * context model
2224      * - encoding: Set by user.
2225      * - decoding: unused
2226      */
2227     int context_model;
2228 #if 0
2229     /**
2230      *
2231      * - encoding: unused
2232      * - decoding: Set by user.
2233      */
2234     uint8_t * (*realloc)(struct AVCodecContext *s, uint8_t *buf, int buf_size);
2235 #endif
2236 
2237     /**
2238      * slice flags
2239      * - encoding: unused
2240      * - decoding: Set by user.
2241      */
2242     int slice_flags;
2243 #define SLICE_FLAG_CODED_ORDER    0x0001 ///< draw_horiz_band() is called in coded order instead of display
2244 #define SLICE_FLAG_ALLOW_FIELD    0x0002 ///< allow draw_horiz_band() with field slices (MPEG2 field pics)
2245 #define SLICE_FLAG_ALLOW_PLANE    0x0004 ///< allow draw_horiz_band() with 1 component at a time (SVQ1)
2246 
2247     /**
2248      * XVideo Motion Acceleration
2249      * - encoding: forbidden
2250      * - decoding: set by decoder
2251      */
2252     int xvmc_acceleration;
2253 
2254     /**
2255      * macroblock decision mode
2256      * - encoding: Set by user.
2257      * - decoding: unused
2258      */
2259     int mb_decision;
2260 #define FF_MB_DECISION_SIMPLE 0        ///< uses mb_cmp
2261 #define FF_MB_DECISION_BITS   1        ///< chooses the one which needs the fewest bits
2262 #define FF_MB_DECISION_RD     2        ///< rate distortion
2263 
2264     /**
2265      * custom intra quantization matrix
2266      * - encoding: Set by user, can be NULL.
2267      * - decoding: Set by libavcodec.
2268      */
2269     uint16_t *intra_matrix;
2270 
2271     /**
2272      * custom inter quantization matrix
2273      * - encoding: Set by user, can be NULL.
2274      * - decoding: Set by libavcodec.
2275      */
2276     uint16_t *inter_matrix;
2277 
2278     /**
2279      * fourcc from the AVI stream header (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
2280      * This is used to work around some encoder bugs.
2281      * - encoding: unused
2282      * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
2283      */
2284     unsigned int stream_codec_tag;
2285 
2286     /**
2287      * scene change detection threshold
2288      * 0 is default, larger means fewer detected scene changes.
2289      * - encoding: Set by user.
2290      * - decoding: unused
2291      */
2292     int scenechange_threshold;
2293 
2294     /**
2295      * minimum Lagrange multipler
2296      * - encoding: Set by user.
2297      * - decoding: unused
2298      */
2299     int lmin;
2300 
2301     /**
2302      * maximum Lagrange multipler
2303      * - encoding: Set by user.
2304      * - decoding: unused
2305      */
2306     int lmax;
2307 
2308 #if FF_API_PALETTE_CONTROL
2309     /**
2310      * palette control structure
2311      * - encoding: ??? (no palette-enabled encoder yet)
2312      * - decoding: Set by user.
2313      */
2314     struct AVPaletteControl *palctrl;
2315 #endif
2316 
2317     /**
2318      * noise reduction strength
2319      * - encoding: Set by user.
2320      * - decoding: unused
2321      */
2322     int noise_reduction;
2323 
2324     /**
2325      * Called at the beginning of a frame to get cr buffer for it.
2326      * Buffer type (size, hints) must be the same. libavcodec won't check it.
2327      * libavcodec will pass previous buffer in pic, function should return
2328      * same buffer or new buffer with old frame "painted" into it.
2329      * If pic.data[0] == NULL must behave like get_buffer().
2330      * if CODEC_CAP_DR1 is not set then reget_buffer() must call
2331      * avcodec_default_reget_buffer() instead of providing buffers allocated by
2332      * some other means.
2333      * - encoding: unused
2334      * - decoding: Set by libavcodec, user can override.
2335      */
2336     int (*reget_buffer)(struct AVCodecContext *c, AVFrame *pic);
2337 
2338     /**
2339      * Number of bits which should be loaded into the rc buffer before decoding starts.
2340      * - encoding: Set by user.
2341      * - decoding: unused
2342      */
2343     int rc_initial_buffer_occupancy;
2344 
2345     /**
2346      *
2347      * - encoding: Set by user.
2348      * - decoding: unused
2349      */
2350     int inter_threshold;
2351 
2352     /**
2353      * CODEC_FLAG2_*
2354      * - encoding: Set by user.
2355      * - decoding: Set by user.
2356      */
2357     int flags2;
2358 
2359     /**
2360      * Simulates errors in the bitstream to test error concealment.
2361      * - encoding: Set by user.
2362      * - decoding: unused
2363      */
2364     int error_rate;
2365 
2366 #if FF_API_ANTIALIAS_ALGO
2367     /**
2368      * MP3 antialias algorithm, see FF_AA_* below.
2369      * - encoding: unused
2370      * - decoding: Set by user.
2371      */
2372     attribute_deprecated int antialias_algo;
2373 #define FF_AA_AUTO    0
2374 #define FF_AA_FASTINT 1 //not implemented yet
2375 #define FF_AA_INT     2
2376 #define FF_AA_FLOAT   3
2377 #endif
2378 
2379     /**
2380      * quantizer noise shaping
2381      * - encoding: Set by user.
2382      * - decoding: unused
2383      */
2384     int quantizer_noise_shaping;
2385 
2386     /**
2387      * thread count
2388      * is used to decide how many independent tasks should be passed to execute()
2389      * - encoding: Set by user.
2390      * - decoding: Set by user.
2391      */
2392     int thread_count;
2393 
2394     /**
2395      * The codec may call this to execute several independent things.
2396      * It will return only after finishing all tasks.
2397      * The user may replace this with some multithreaded implementation,
2398      * the default implementation will execute the parts serially.
2399      * @param count the number of things to execute
2400      * - encoding: Set by libavcodec, user can override.
2401      * - decoding: Set by libavcodec, user can override.
2402      */
2403     int (*execute)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size);
2404 
2405     /**
2406      * thread opaque
2407      * Can be used by execute() to store some per AVCodecContext stuff.
2408      * - encoding: set by execute()
2409      * - decoding: set by execute()
2410      */
2411     void *thread_opaque;
2412 
2413     /**
2414      * Motion estimation threshold below which no motion estimation is
2415      * performed, but instead the user specified motion vectors are used.
2416      *
2417      * - encoding: Set by user.
2418      * - decoding: unused
2419      */
2420      int me_threshold;
2421 
2422     /**
2423      * Macroblock threshold below which the user specified macroblock types will be used.
2424      * - encoding: Set by user.
2425      * - decoding: unused
2426      */
2427      int mb_threshold;
2428 
2429     /**
2430      * precision of the intra DC coefficient - 8
2431      * - encoding: Set by user.
2432      * - decoding: unused
2433      */
2434      int intra_dc_precision;
2435 
2436     /**
2437      * noise vs. sse weight for the nsse comparsion function
2438      * - encoding: Set by user.
2439      * - decoding: unused
2440      */
2441      int nsse_weight;
2442 
2443     /**
2444      * Number of macroblock rows at the top which are skipped.
2445      * - encoding: unused
2446      * - decoding: Set by user.
2447      */
2448      int skip_top;
2449 
2450     /**
2451      * Number of macroblock rows at the bottom which are skipped.
2452      * - encoding: unused
2453      * - decoding: Set by user.
2454      */
2455      int skip_bottom;
2456 
2457     /**
2458      * profile
2459      * - encoding: Set by user.
2460      * - decoding: Set by libavcodec.
2461      */
2462      int profile;
2463 #define FF_PROFILE_UNKNOWN -99
2464 #define FF_PROFILE_RESERVED -100
2465 
2466 #define FF_PROFILE_AAC_MAIN 0
2467 #define FF_PROFILE_AAC_LOW  1
2468 #define FF_PROFILE_AAC_SSR  2
2469 #define FF_PROFILE_AAC_LTP  3
2470 
2471 #define FF_PROFILE_DTS         20
2472 #define FF_PROFILE_DTS_ES      30
2473 #define FF_PROFILE_DTS_96_24   40
2474 #define FF_PROFILE_DTS_HD_HRA  50
2475 #define FF_PROFILE_DTS_HD_MA   60
2476 
2477 #define FF_PROFILE_MPEG2_422    0
2478 #define FF_PROFILE_MPEG2_HIGH   1
2479 #define FF_PROFILE_MPEG2_SS     2
2480 #define FF_PROFILE_MPEG2_SNR_SCALABLE  3
2481 #define FF_PROFILE_MPEG2_MAIN   4
2482 #define FF_PROFILE_MPEG2_SIMPLE 5
2483 
2484 #define FF_PROFILE_H264_CONSTRAINED  (1<<9)  // 8+1; constraint_set1_flag
2485 #define FF_PROFILE_H264_INTRA        (1<<11) // 8+3; constraint_set3_flag
2486 
2487 #define FF_PROFILE_H264_BASELINE             66
2488 #define FF_PROFILE_H264_CONSTRAINED_BASELINE (66|FF_PROFILE_H264_CONSTRAINED)
2489 #define FF_PROFILE_H264_MAIN                 77
2490 #define FF_PROFILE_H264_EXTENDED             88
2491 #define FF_PROFILE_H264_HIGH                 100
2492 #define FF_PROFILE_H264_HIGH_10              110
2493 #define FF_PROFILE_H264_HIGH_10_INTRA        (110|FF_PROFILE_H264_INTRA)
2494 #define FF_PROFILE_H264_HIGH_422             122
2495 #define FF_PROFILE_H264_HIGH_422_INTRA       (122|FF_PROFILE_H264_INTRA)
2496 #define FF_PROFILE_H264_HIGH_444             144
2497 #define FF_PROFILE_H264_HIGH_444_PREDICTIVE  244
2498 #define FF_PROFILE_H264_HIGH_444_INTRA       (244|FF_PROFILE_H264_INTRA)
2499 #define FF_PROFILE_H264_CAVLC_444            44
2500 
2501 #define FF_PROFILE_VC1_SIMPLE   0
2502 #define FF_PROFILE_VC1_MAIN     1
2503 #define FF_PROFILE_VC1_COMPLEX  2
2504 #define FF_PROFILE_VC1_ADVANCED 3
2505 
2506 #define FF_PROFILE_MPEG4_SIMPLE                     0
2507 #define FF_PROFILE_MPEG4_SIMPLE_SCALABLE            1
2508 #define FF_PROFILE_MPEG4_CORE                       2
2509 #define FF_PROFILE_MPEG4_MAIN                       3
2510 #define FF_PROFILE_MPEG4_N_BIT                      4
2511 #define FF_PROFILE_MPEG4_SCALABLE_TEXTURE           5
2512 #define FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION      6
2513 #define FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE     7
2514 #define FF_PROFILE_MPEG4_HYBRID                     8
2515 #define FF_PROFILE_MPEG4_ADVANCED_REAL_TIME         9
2516 #define FF_PROFILE_MPEG4_CORE_SCALABLE             10
2517 #define FF_PROFILE_MPEG4_ADVANCED_CODING           11
2518 #define FF_PROFILE_MPEG4_ADVANCED_CORE             12
2519 #define FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE 13
2520 #define FF_PROFILE_MPEG4_SIMPLE_STUDIO             14
2521 #define FF_PROFILE_MPEG4_ADVANCED_SIMPLE           15
2522 
2523     /**
2524      * level
2525      * - encoding: Set by user.
2526      * - decoding: Set by libavcodec.
2527      */
2528      int level;
2529 #define FF_LEVEL_UNKNOWN -99
2530 
2531     /**
2532      * low resolution decoding, 1-> 1/2 size, 2->1/4 size
2533      * - encoding: unused
2534      * - decoding: Set by user.
2535      */
2536      int lowres;
2537 
2538     /**
2539      * Bitstream width / height, may be different from width/height if lowres enabled.
2540      * - encoding: unused
2541      * - decoding: Set by user before init if known. Codec should override / dynamically change if needed.
2542      */
2543     int coded_width, coded_height;
2544 
2545     /**
2546      * frame skip threshold
2547      * - encoding: Set by user.
2548      * - decoding: unused
2549      */
2550     int frame_skip_threshold;
2551 
2552     /**
2553      * frame skip factor
2554      * - encoding: Set by user.
2555      * - decoding: unused
2556      */
2557     int frame_skip_factor;
2558 
2559     /**
2560      * frame skip exponent
2561      * - encoding: Set by user.
2562      * - decoding: unused
2563      */
2564     int frame_skip_exp;
2565 
2566     /**
2567      * frame skip comparison function
2568      * - encoding: Set by user.
2569      * - decoding: unused
2570      */
2571     int frame_skip_cmp;
2572 
2573     /**
2574      * Border processing masking, raises the quantizer for mbs on the borders
2575      * of the picture.
2576      * - encoding: Set by user.
2577      * - decoding: unused
2578      */
2579     float border_masking;
2580 
2581     /**
2582      * minimum MB lagrange multipler
2583      * - encoding: Set by user.
2584      * - decoding: unused
2585      */
2586     int mb_lmin;
2587 
2588     /**
2589      * maximum MB lagrange multipler
2590      * - encoding: Set by user.
2591      * - decoding: unused
2592      */
2593     int mb_lmax;
2594 
2595     /**
2596      *
2597      * - encoding: Set by user.
2598      * - decoding: unused
2599      */
2600     int me_penalty_compensation;
2601 
2602     /**
2603      *
2604      * - encoding: unused
2605      * - decoding: Set by user.
2606      */
2607     enum AVDiscard skip_loop_filter;
2608 
2609     /**
2610      *
2611      * - encoding: unused
2612      * - decoding: Set by user.
2613      */
2614     enum AVDiscard skip_idct;
2615 
2616     /**
2617      *
2618      * - encoding: unused
2619      * - decoding: Set by user.
2620      */
2621     enum AVDiscard skip_frame;
2622 
2623     /**
2624      *
2625      * - encoding: Set by user.
2626      * - decoding: unused
2627      */
2628     int bidir_refine;
2629 
2630     /**
2631      *
2632      * - encoding: Set by user.
2633      * - decoding: unused
2634      */
2635     int brd_scale;
2636 
2637 #if FF_API_X264_GLOBAL_OPTS
2638     /**
2639      * constant rate factor - quality-based VBR - values ~correspond to qps
2640      * - encoding: Set by user.
2641      * - decoding: unused
2642      *   @deprecated use 'crf' libx264 private option
2643      */
2644     attribute_deprecated float crf;
2645 
2646     /**
2647      * constant quantization parameter rate control method
2648      * - encoding: Set by user.
2649      * - decoding: unused
2650      *   @deprecated use 'cqp' libx264 private option
2651      */
2652     attribute_deprecated int cqp;
2653 #endif
2654 
2655     /**
2656      * minimum GOP size
2657      * - encoding: Set by user.
2658      * - decoding: unused
2659      */
2660     int keyint_min;
2661 
2662     /**
2663      * number of reference frames
2664      * - encoding: Set by user.
2665      * - decoding: Set by lavc.
2666      */
2667     int refs;
2668 
2669     /**
2670      * chroma qp offset from luma
2671      * - encoding: Set by user.
2672      * - decoding: unused
2673      */
2674     int chromaoffset;
2675 
2676 #if FF_API_X264_GLOBAL_OPTS
2677     /**
2678      * Influence how often B-frames are used.
2679      * - encoding: Set by user.
2680      * - decoding: unused
2681      */
2682     attribute_deprecated int bframebias;
2683 #endif
2684 
2685     /**
2686      * trellis RD quantization
2687      * - encoding: Set by user.
2688      * - decoding: unused
2689      */
2690     int trellis;
2691 
2692 #if FF_API_X264_GLOBAL_OPTS
2693     /**
2694      * Reduce fluctuations in qp (before curve compression).
2695      * - encoding: Set by user.
2696      * - decoding: unused
2697      */
2698     attribute_deprecated float complexityblur;
2699 
2700     /**
2701      * in-loop deblocking filter alphac0 parameter
2702      * alpha is in the range -6...6
2703      * - encoding: Set by user.
2704      * - decoding: unused
2705      */
2706     attribute_deprecated int deblockalpha;
2707 
2708     /**
2709      * in-loop deblocking filter beta parameter
2710      * beta is in the range -6...6
2711      * - encoding: Set by user.
2712      * - decoding: unused
2713      */
2714     attribute_deprecated int deblockbeta;
2715 
2716     /**
2717      * macroblock subpartition sizes to consider - p8x8, p4x4, b8x8, i8x8, i4x4
2718      * - encoding: Set by user.
2719      * - decoding: unused
2720      */
2721     attribute_deprecated int partitions;
2722 #define X264_PART_I4X4 0x001  /* Analyze i4x4 */
2723 #define X264_PART_I8X8 0x002  /* Analyze i8x8 (requires 8x8 transform) */
2724 #define X264_PART_P8X8 0x010  /* Analyze p16x8, p8x16 and p8x8 */
2725 #define X264_PART_P4X4 0x020  /* Analyze p8x4, p4x8, p4x4 */
2726 #define X264_PART_B8X8 0x100  /* Analyze b16x8, b8x16 and b8x8 */
2727 
2728     /**
2729      * direct MV prediction mode - 0 (none), 1 (spatial), 2 (temporal), 3 (auto)
2730      * - encoding: Set by user.
2731      * - decoding: unused
2732      */
2733     attribute_deprecated int directpred;
2734 #endif
2735 
2736     /**
2737      * Audio cutoff bandwidth (0 means "automatic")
2738      * - encoding: Set by user.
2739      * - decoding: unused
2740      */
2741     int cutoff;
2742 
2743     /**
2744      * Multiplied by qscale for each frame and added to scene_change_score.
2745      * - encoding: Set by user.
2746      * - decoding: unused
2747      */
2748     int scenechange_factor;
2749 
2750     /**
2751      *
2752      * Note: Value depends upon the compare function used for fullpel ME.
2753      * - encoding: Set by user.
2754      * - decoding: unused
2755      */
2756     int mv0_threshold;
2757 
2758     /**
2759      * Adjust sensitivity of b_frame_strategy 1.
2760      * - encoding: Set by user.
2761      * - decoding: unused
2762      */
2763     int b_sensitivity;
2764 
2765     /**
2766      * - encoding: Set by user.
2767      * - decoding: unused
2768      */
2769     int compression_level;
2770 #define FF_COMPRESSION_DEFAULT -1
2771 
2772     /**
2773      * - encoding: Set by user.
2774      * - decoding: unused
2775      */
2776     int min_prediction_order;
2777 
2778     /**
2779      * - encoding: Set by user.
2780      * - decoding: unused
2781      */
2782     int max_prediction_order;
2783 
2784 #if FF_API_FLAC_GLOBAL_OPTS
2785     /**
2786      * @name FLAC options
2787      * @deprecated Use FLAC encoder private options instead.
2788      * @{
2789      */
2790 
2791     /**
2792      * LPC coefficient precision - used by FLAC encoder
2793      * - encoding: Set by user.
2794      * - decoding: unused
2795      */
2796     attribute_deprecated int lpc_coeff_precision;
2797 
2798     /**
2799      * search method for selecting prediction order
2800      * - encoding: Set by user.
2801      * - decoding: unused
2802      */
2803     attribute_deprecated int prediction_order_method;
2804 
2805     /**
2806      * - encoding: Set by user.
2807      * - decoding: unused
2808      */
2809     attribute_deprecated int min_partition_order;
2810 
2811     /**
2812      * - encoding: Set by user.
2813      * - decoding: unused
2814      */
2815     attribute_deprecated int max_partition_order;
2816     /**
2817      * @}
2818      */
2819 #endif
2820 
2821     /**
2822      * GOP timecode frame start number, in non drop frame format
2823      * - encoding: Set by user.
2824      * - decoding: unused
2825      */
2826     int64_t timecode_frame_start;
2827 
2828 #if FF_API_REQUEST_CHANNELS
2829     /**
2830      * Decoder should decode to this many channels if it can (0 for default)
2831      * - encoding: unused
2832      * - decoding: Set by user.
2833      * @deprecated Deprecated in favor of request_channel_layout.
2834      */
2835     int request_channels;
2836 #endif
2837 
2838 #if FF_API_DRC_SCALE
2839     /**
2840      * Percentage of dynamic range compression to be applied by the decoder.
2841      * The default value is 1.0, corresponding to full compression.
2842      * - encoding: unused
2843      * - decoding: Set by user.
2844      * @deprecated use AC3 decoder private option instead.
2845      */
2846     attribute_deprecated float drc_scale;
2847 #endif
2848 
2849     /**
2850      * opaque 64bit number (generally a PTS) that will be reordered and
2851      * output in AVFrame.reordered_opaque
2852      * @deprecated in favor of pkt_pts
2853      * - encoding: unused
2854      * - decoding: Set by user.
2855      */
2856     int64_t reordered_opaque;
2857 
2858     /**
2859      * Bits per sample/pixel of internal libavcodec pixel/sample format.
2860      * - encoding: set by user.
2861      * - decoding: set by libavcodec.
2862      */
2863     int bits_per_raw_sample;
2864 
2865     /**
2866      * Audio channel layout.
2867      * - encoding: set by user.
2868      * - decoding: set by libavcodec.
2869      */
2870     uint64_t channel_layout;
2871 
2872     /**
2873      * Request decoder to use this channel layout if it can (0 for default)
2874      * - encoding: unused
2875      * - decoding: Set by user.
2876      */
2877     uint64_t request_channel_layout;
2878 
2879     /**
2880      * Ratecontrol attempt to use, at maximum, <value> of what can be used without an underflow.
2881      * - encoding: Set by user.
2882      * - decoding: unused.
2883      */
2884     float rc_max_available_vbv_use;
2885 
2886     /**
2887      * Ratecontrol attempt to use, at least, <value> times the amount needed to prevent a vbv overflow.
2888      * - encoding: Set by user.
2889      * - decoding: unused.
2890      */
2891     float rc_min_vbv_overflow_use;
2892 
2893     /**
2894      * Hardware accelerator in use
2895      * - encoding: unused.
2896      * - decoding: Set by libavcodec
2897      */
2898     struct AVHWAccel *hwaccel;
2899 
2900     /**
2901      * For some codecs, the time base is closer to the field rate than the frame rate.
2902      * Most notably, H.264 and MPEG-2 specify time_base as half of frame duration
2903      * if no telecine is used ...
2904      *
2905      * Set to time_base ticks per frame. Default 1, e.g., H.264/MPEG-2 set it to 2.
2906      */
2907     int ticks_per_frame;
2908 
2909     /**
2910      * Hardware accelerator context.
2911      * For some hardware accelerators, a global context needs to be
2912      * provided by the user. In that case, this holds display-dependent
2913      * data Libav cannot instantiate itself. Please refer to the
2914      * Libav HW accelerator documentation to know how to fill this
2915      * is. e.g. for VA API, this is a struct vaapi_context.
2916      * - encoding: unused
2917      * - decoding: Set by user
2918      */
2919     void *hwaccel_context;
2920 
2921     /**
2922      * Chromaticity coordinates of the source primaries.
2923      * - encoding: Set by user
2924      * - decoding: Set by libavcodec
2925      */
2926     enum AVColorPrimaries color_primaries;
2927 
2928     /**
2929      * Color Transfer Characteristic.
2930      * - encoding: Set by user
2931      * - decoding: Set by libavcodec
2932      */
2933     enum AVColorTransferCharacteristic color_trc;
2934 
2935     /**
2936      * YUV colorspace type.
2937      * - encoding: Set by user
2938      * - decoding: Set by libavcodec
2939      */
2940     enum AVColorSpace colorspace;
2941 
2942     /**
2943      * MPEG vs JPEG YUV range.
2944      * - encoding: Set by user
2945      * - decoding: Set by libavcodec
2946      */
2947     enum AVColorRange color_range;
2948 
2949     /**
2950      * This defines the location of chroma samples.
2951      * - encoding: Set by user
2952      * - decoding: Set by libavcodec
2953      */
2954     enum AVChromaLocation chroma_sample_location;
2955 
2956     /**
2957      * The codec may call this to execute several independent things.
2958      * It will return only after finishing all tasks.
2959      * The user may replace this with some multithreaded implementation,
2960      * the default implementation will execute the parts serially.
2961      * Also see avcodec_thread_init and e.g. the --enable-pthread configure option.
2962      * @param c context passed also to func
2963      * @param count the number of things to execute
2964      * @param arg2 argument passed unchanged to func
2965      * @param ret return values of executed functions, must have space for "count" values. May be NULL.
2966      * @param func function that will be called count times, with jobnr from 0 to count-1.
2967      *             threadnr will be in the range 0 to c->thread_count-1 < MAX_THREADS and so that no
2968      *             two instances of func executing at the same time will have the same threadnr.
2969      * @return always 0 currently, but code should handle a future improvement where when any call to func
2970      *         returns < 0 no further calls to func may be done and < 0 is returned.
2971      * - encoding: Set by libavcodec, user can override.
2972      * - decoding: Set by libavcodec, user can override.
2973      */
2974     int (*execute2)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count);
2975 
2976 #if FF_API_X264_GLOBAL_OPTS
2977     /**
2978      * explicit P-frame weighted prediction analysis method
2979      * 0: off
2980      * 1: fast blind weighting (one reference duplicate with -1 offset)
2981      * 2: smart weighting (full fade detection analysis)
2982      * - encoding: Set by user.
2983      * - decoding: unused
2984      */
2985     attribute_deprecated int weighted_p_pred;
2986 
2987     /**
2988      * AQ mode
2989      * 0: Disabled
2990      * 1: Variance AQ (complexity mask)
2991      * 2: Auto-variance AQ (experimental)
2992      * - encoding: Set by user
2993      * - decoding: unused
2994      */
2995     attribute_deprecated int aq_mode;
2996 
2997     /**
2998      * AQ strength
2999      * Reduces blocking and blurring in flat and textured areas.
3000      * - encoding: Set by user
3001      * - decoding: unused
3002      */
3003     attribute_deprecated float aq_strength;
3004 
3005     /**
3006      * PSY RD
3007      * Strength of psychovisual optimization
3008      * - encoding: Set by user
3009      * - decoding: unused
3010      */
3011     attribute_deprecated float psy_rd;
3012 
3013     /**
3014      * PSY trellis
3015      * Strength of psychovisual optimization
3016      * - encoding: Set by user
3017      * - decoding: unused
3018      */
3019     attribute_deprecated float psy_trellis;
3020 
3021     /**
3022      * RC lookahead
3023      * Number of frames for frametype and ratecontrol lookahead
3024      * - encoding: Set by user
3025      * - decoding: unused
3026      */
3027     attribute_deprecated int rc_lookahead;
3028 
3029     /**
3030      * Constant rate factor maximum
3031      * With CRF encoding mode and VBV restrictions enabled, prevents quality from being worse
3032      * than crf_max, even if doing so would violate VBV restrictions.
3033      * - encoding: Set by user.
3034      * - decoding: unused
3035      */
3036     attribute_deprecated float crf_max;
3037 #endif
3038 
3039     int log_level_offset;
3040 
3041 #if FF_API_FLAC_GLOBAL_OPTS
3042     /**
3043      * Determine which LPC analysis algorithm to use.
3044      * - encoding: Set by user
3045      * - decoding: unused
3046      */
3047     attribute_deprecated enum AVLPCType lpc_type;
3048 
3049     /**
3050      * Number of passes to use for Cholesky factorization during LPC analysis
3051      * - encoding: Set by user
3052      * - decoding: unused
3053      */
3054     attribute_deprecated int lpc_passes;
3055 #endif
3056 
3057     /**
3058      * Number of slices.
3059      * Indicates number of picture subdivisions. Used for parallelized
3060      * decoding.
3061      * - encoding: Set by user
3062      * - decoding: unused
3063      */
3064     int slices;
3065 
3066     /**
3067      * Header containing style information for text subtitles.
3068      * For SUBTITLE_ASS subtitle type, it should contain the whole ASS
3069      * [Script Info] and [V4+ Styles] section, plus the [Events] line and
3070      * the Format line following. It shouldn't include any Dialogue line.
3071      * - encoding: Set/allocated/freed by user (before avcodec_open2())
3072      * - decoding: Set/allocated/freed by libavcodec (by avcodec_open2())
3073      */
3074     uint8_t *subtitle_header;
3075     int subtitle_header_size;
3076 
3077     /**
3078      * Current packet as passed into the decoder, to avoid having
3079      * to pass the packet into every function. Currently only valid
3080      * inside lavc and get/release_buffer callbacks.
3081      * - decoding: set by avcodec_decode_*, read by get_buffer() for setting pkt_pts
3082      * - encoding: unused
3083      */
3084     AVPacket *pkt;
3085 
3086 #if FF_API_INTERNAL_CONTEXT
3087     /**
3088      * Whether this is a copy of the context which had init() called on it.
3089      * This is used by multithreading - shared tables and picture pointers
3090      * should be freed from the original context only.
3091      * - encoding: Set by libavcodec.
3092      * - decoding: Set by libavcodec.
3093      *
3094      * @deprecated this field has been moved to an internal context
3095      */
3096     attribute_deprecated int is_copy;
3097 #endif
3098 
3099     /**
3100      * Which multithreading methods to use.
3101      * Use of FF_THREAD_FRAME will increase decoding delay by one frame per thread,
3102      * so clients which cannot provide future frames should not use it.
3103      *
3104      * - encoding: Set by user, otherwise the default is used.
3105      * - decoding: Set by user, otherwise the default is used.
3106      */
3107     int thread_type;
3108 #define FF_THREAD_FRAME   1 ///< Decode more than one frame at once
3109 #define FF_THREAD_SLICE   2 ///< Decode more than one part of a single frame at once
3110 
3111     /**
3112      * Which multithreading methods are in use by the codec.
3113      * - encoding: Set by libavcodec.
3114      * - decoding: Set by libavcodec.
3115      */
3116     int active_thread_type;
3117 
3118     /**
3119      * Set by the client if its custom get_buffer() callback can be called
3120      * from another thread, which allows faster multithreaded decoding.
3121      * draw_horiz_band() will be called from other threads regardless of this setting.
3122      * Ignored if the default get_buffer() is used.
3123      * - encoding: Set by user.
3124      * - decoding: Set by user.
3125      */
3126     int thread_safe_callbacks;
3127 
3128     /**
3129      * VBV delay coded in the last frame (in periods of a 27 MHz clock).
3130      * Used for compliant TS muxing.
3131      * - encoding: Set by libavcodec.
3132      * - decoding: unused.
3133      */
3134     uint64_t vbv_delay;
3135 
3136     /**
3137      * Type of service that the audio stream conveys.
3138      * - encoding: Set by user.
3139      * - decoding: Set by libavcodec.
3140      */
3141     enum AVAudioServiceType audio_service_type;
3142 
3143     /**
3144      * Used to request a sample format from the decoder.
3145      * - encoding: unused.
3146      * - decoding: Set by user.
3147      */
3148     enum AVSampleFormat request_sample_fmt;
3149 
3150     /**
3151      * Error recognition; may misdetect some more or less valid parts as errors.
3152      * - encoding: unused
3153      * - decoding: Set by user.
3154      */
3155     int err_recognition;
3156 #define AV_EF_CRCCHECK  (1<<0)
3157 #define AV_EF_BITSTREAM (1<<1)
3158 #define AV_EF_BUFFER    (1<<2)
3159 #define AV_EF_EXPLODE   (1<<3)
3160 
3161     /**
3162      * Private context used for internal data.
3163      *
3164      * Unlike priv_data, this is not codec-specific. It is used in general
3165      * libavcodec functions.
3166      */
3167     struct AVCodecInternal *internal;
3168 
3169     /** Field order
3170      * - encoding: set by libavcodec
3171      * - decoding: Set by libavcodec
3172      */
3173     enum AVFieldOrder field_order;
3174 } AVCodecContext;
3175 
3176 /**
3177  * AVProfile.
3178  */
3179 typedef struct AVProfile {
3180     int profile;
3181     const char *name; ///< short name for the profile
3182 } AVProfile;
3183 
3184 typedef struct AVCodecDefault AVCodecDefault;
3185 
3186 /**
3187  * AVCodec.
3188  */
3189 typedef struct AVCodec {
3190     /**
3191      * Name of the codec implementation.
3192      * The name is globally unique among encoders and among decoders (but an
3193      * encoder and a decoder can share the same name).
3194      * This is the primary way to find a codec from the user perspective.
3195      */
3196     const char *name;
3197     enum AVMediaType type;
3198     enum CodecID id;
3199     int priv_data_size;
3200     int (*init)(AVCodecContext *);
3201     int (*encode)(AVCodecContext *, uint8_t *buf, int buf_size, void *data);
3202     int (*close)(AVCodecContext *);
3203     int (*decode)(AVCodecContext *, void *outdata, int *outdata_size, AVPacket *avpkt);
3204     /**
3205      * Codec capabilities.
3206      * see CODEC_CAP_*
3207      */
3208     int capabilities;
3209     struct AVCodec *next;
3210     /**
3211      * Flush buffers.
3212      * Will be called when seeking
3213      */
3214     void (*flush)(AVCodecContext *);
3215     const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0}
3216     const enum PixelFormat *pix_fmts;       ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1
3217     /**
3218      * Descriptive name for the codec, meant to be more human readable than name.
3219      * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
3220      */
3221     const char *long_name;
3222     const int *supported_samplerates;       ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0
3223     const enum AVSampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1
3224     const uint64_t *channel_layouts;         ///< array of support channel layouts, or NULL if unknown. array is terminated by 0
3225     uint8_t max_lowres;                     ///< maximum value for lowres supported by the decoder
3226     const AVClass *priv_class;              ///< AVClass for the private context
3227     const AVProfile *profiles;              ///< array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}
3228 
3229     /**
3230      * @name Frame-level threading support functions
3231      * @{
3232      */
3233     /**
3234      * If defined, called on thread contexts when they are created.
3235      * If the codec allocates writable tables in init(), re-allocate them here.
3236      * priv_data will be set to a copy of the original.
3237      */
3238     int (*init_thread_copy)(AVCodecContext *);
3239     /**
3240      * Copy necessary context variables from a previous thread context to the current one.
3241      * If not defined, the next thread will start automatically; otherwise, the codec
3242      * must call ff_thread_finish_setup().
3243      *
3244      * dst and src will (rarely) point to the same context, in which case memcpy should be skipped.
3245      */
3246     int (*update_thread_context)(AVCodecContext *dst, const AVCodecContext *src);
3247     /** @} */
3248 
3249     /**
3250      * Private codec-specific defaults.
3251      */
3252     const AVCodecDefault *defaults;
3253 
3254     /**
3255      * Initialize codec static data, called from avcodec_register().
3256      */
3257     void (*init_static_data)(struct AVCodec *codec);
3258 
3259     /**
3260      * Encode data to an AVPacket.
3261      *
3262      * @param      avctx          codec context
3263      * @param      avpkt          output AVPacket (may contain a user-provided buffer)
3264      * @param[in]  frame          AVFrame containing the raw data to be encoded
3265      * @param[out] got_packet_ptr encoder sets to 0 or 1 to indicate that a
3266      *                            non-empty packet was returned in avpkt.
3267      * @return 0 on success, negative error code on failure
3268      */
3269     int (*encode2)(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame,
3270                    int *got_packet_ptr);
3271 } AVCodec;
3272 
3273 /**
3274  * AVHWAccel.
3275  */
3276 typedef struct AVHWAccel {
3277     /**
3278      * Name of the hardware accelerated codec.
3279      * The name is globally unique among encoders and among decoders (but an
3280      * encoder and a decoder can share the same name).
3281      */
3282     const char *name;
3283 
3284     /**
3285      * Type of codec implemented by the hardware accelerator.
3286      *
3287      * See AVMEDIA_TYPE_xxx
3288      */
3289     enum AVMediaType type;
3290 
3291     /**
3292      * Codec implemented by the hardware accelerator.
3293      *
3294      * See CODEC_ID_xxx
3295      */
3296     enum CodecID id;
3297 
3298     /**
3299      * Supported pixel format.
3300      *
3301      * Only hardware accelerated formats are supported here.
3302      */
3303     enum PixelFormat pix_fmt;
3304 
3305     /**
3306      * Hardware accelerated codec capabilities.
3307      * see FF_HWACCEL_CODEC_CAP_*
3308      */
3309     int capabilities;
3310 
3311     struct AVHWAccel *next;
3312 
3313     /**
3314      * Called at the beginning of each frame or field picture.
3315      *
3316      * Meaningful frame information (codec specific) is guaranteed to
3317      * be parsed at this point. This function is mandatory.
3318      *
3319      * Note that buf can be NULL along with buf_size set to 0.
3320      * Otherwise, this means the whole frame is available at this point.
3321      *
3322      * @param avctx the codec context
3323      * @param buf the frame data buffer base
3324      * @param buf_size the size of the frame in bytes
3325      * @return zero if successful, a negative value otherwise
3326      */
3327     int (*start_frame)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
3328 
3329     /**
3330      * Callback for each slice.
3331      *
3332      * Meaningful slice information (codec specific) is guaranteed to
3333      * be parsed at this point. This function is mandatory.
3334      *
3335      * @param avctx the codec context
3336      * @param buf the slice data buffer base
3337      * @param buf_size the size of the slice in bytes
3338      * @return zero if successful, a negative value otherwise
3339      */
3340     int (*decode_slice)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
3341 
3342     /**
3343      * Called at the end of each frame or field picture.
3344      *
3345      * The whole picture is parsed at this point and can now be sent
3346      * to the hardware accelerator. This function is mandatory.
3347      *
3348      * @param avctx the codec context
3349      * @return zero if successful, a negative value otherwise
3350      */
3351     int (*end_frame)(AVCodecContext *avctx);
3352 
3353     /**
3354      * Size of HW accelerator private data.
3355      *
3356      * Private data is allocated with av_mallocz() before
3357      * AVCodecContext.get_buffer() and deallocated after
3358      * AVCodecContext.release_buffer().
3359      */
3360     int priv_data_size;
3361 } AVHWAccel;
3362 
3363 /**
3364  * four components are given, that's all.
3365  * the last component is alpha
3366  */
3367 typedef struct AVPicture {
3368     uint8_t *data[AV_NUM_DATA_POINTERS];
3369     int linesize[AV_NUM_DATA_POINTERS];     ///< number of bytes per line
3370 } AVPicture;
3371 
3372 #define AVPALETTE_SIZE 1024
3373 #define AVPALETTE_COUNT 256
3374 #if FF_API_PALETTE_CONTROL
3375 /**
3376  * AVPaletteControl
3377  * This structure defines a method for communicating palette changes
3378  * between and demuxer and a decoder.
3379  *
3380  * @deprecated Use AVPacket to send palette changes instead.
3381  * This is totally broken.
3382  */
3383 typedef struct AVPaletteControl {
3384 
3385     /* Demuxer sets this to 1 to indicate the palette has changed;
3386      * decoder resets to 0. */
3387     int palette_changed;
3388 
3389     /* 4-byte ARGB palette entries, stored in native byte order; note that
3390      * the individual palette components should be on a 8-bit scale; if
3391      * the palette data comes from an IBM VGA native format, the component
3392      * data is probably 6 bits in size and needs to be scaled. */
3393     unsigned int palette[AVPALETTE_COUNT];
3394 
3395 } AVPaletteControl attribute_deprecated;
3396 #endif
3397 
3398 enum AVSubtitleType {
3399     SUBTITLE_NONE,
3400 
3401     SUBTITLE_BITMAP,                ///< A bitmap, pict will be set
3402 
3403     /**
3404      * Plain text, the text field must be set by the decoder and is
3405      * authoritative. ass and pict fields may contain approximations.
3406      */
3407     SUBTITLE_TEXT,
3408 
3409     /**
3410      * Formatted text, the ass field must be set by the decoder and is
3411      * authoritative. pict and text fields may contain approximations.
3412      */
3413     SUBTITLE_ASS,
3414 };
3415 
3416 typedef struct AVSubtitleRect {
3417     int x;         ///< top left corner  of pict, undefined when pict is not set
3418     int y;         ///< top left corner  of pict, undefined when pict is not set
3419     int w;         ///< width            of pict, undefined when pict is not set
3420     int h;         ///< height           of pict, undefined when pict is not set
3421     int nb_colors; ///< number of colors in pict, undefined when pict is not set
3422 
3423     /**
3424      * data+linesize for the bitmap of this subtitle.
3425      * can be set for text/ass as well once they where rendered
3426      */
3427     AVPicture pict;
3428     enum AVSubtitleType type;
3429 
3430     char *text;                     ///< 0 terminated plain UTF-8 text
3431 
3432     /**
3433      * 0 terminated ASS/SSA compatible event line.
3434      * The pressentation of this is unaffected by the other values in this
3435      * struct.
3436      */
3437     char *ass;
3438 } AVSubtitleRect;
3439 
3440 typedef struct AVSubtitle {
3441     uint16_t format; /* 0 = graphics */
3442     uint32_t start_display_time; /* relative to packet pts, in ms */
3443     uint32_t end_display_time; /* relative to packet pts, in ms */
3444     unsigned num_rects;
3445     AVSubtitleRect **rects;
3446     int64_t pts;    ///< Same as packet pts, in AV_TIME_BASE
3447 } AVSubtitle;
3448 
3449 /* packet functions */
3450 
3451 /**
3452  * @deprecated use NULL instead
3453  */
3454 attribute_deprecated void av_destruct_packet_nofree(AVPacket *pkt);
3455 
3456 /**
3457  * Default packet destructor.
3458  */
3459 void av_destruct_packet(AVPacket *pkt);
3460 
3461 /**
3462  * Initialize optional fields of a packet with default values.
3463  *
3464  * @param pkt packet
3465  */
3466 void av_init_packet(AVPacket *pkt);
3467 
3468 /**
3469  * Allocate the payload of a packet and initialize its fields with
3470  * default values.
3471  *
3472  * @param pkt packet
3473  * @param size wanted payload size
3474  * @return 0 if OK, AVERROR_xxx otherwise
3475  */
3476 int av_new_packet(AVPacket *pkt, int size);
3477 
3478 /**
3479  * Reduce packet size, correctly zeroing padding
3480  *
3481  * @param pkt packet
3482  * @param size new size
3483  */
3484 void av_shrink_packet(AVPacket *pkt, int size);
3485 
3486 /**
3487  * Increase packet size, correctly zeroing padding
3488  *
3489  * @param pkt packet
3490  * @param grow_by number of bytes by which to increase the size of the packet
3491  */
3492 int av_grow_packet(AVPacket *pkt, int grow_by);
3493 
3494 /**
3495  * @warning This is a hack - the packet memory allocation stuff is broken. The
3496  * packet is allocated if it was not really allocated.
3497  */
3498 int av_dup_packet(AVPacket *pkt);
3499 
3500 /**
3501  * Free a packet.
3502  *
3503  * @param pkt packet to free
3504  */
3505 void av_free_packet(AVPacket *pkt);
3506 
3507 /**
3508  * Allocate new information of a packet.
3509  *
3510  * @param pkt packet
3511  * @param type side information type
3512  * @param size side information size
3513  * @return pointer to fresh allocated data or NULL otherwise
3514  */
3515 uint8_t* av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
3516                                  int size);
3517 
3518 /**
3519  * Get side information from packet.
3520  *
3521  * @param pkt packet
3522  * @param type desired side information type
3523  * @param size pointer for side information size to store (optional)
3524  * @return pointer to data if present or NULL otherwise
3525  */
3526 uint8_t* av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
3527                                  int *size);
3528 
3529 /* resample.c */
3530 
3531 struct ReSampleContext;
3532 struct AVResampleContext;
3533 
3534 typedef struct ReSampleContext ReSampleContext;
3535 
3536 /**
3537  *  Initialize audio resampling context.
3538  *
3539  * @param output_channels  number of output channels
3540  * @param input_channels   number of input channels
3541  * @param output_rate      output sample rate
3542  * @param input_rate       input sample rate
3543  * @param sample_fmt_out   requested output sample format
3544  * @param sample_fmt_in    input sample format
3545  * @param filter_length    length of each FIR filter in the filterbank relative to the cutoff frequency
3546  * @param log2_phase_count log2 of the number of entries in the polyphase filterbank
3547  * @param linear           if 1 then the used FIR filter will be linearly interpolated
3548                            between the 2 closest, if 0 the closest will be used
3549  * @param cutoff           cutoff frequency, 1.0 corresponds to half the output sampling rate
3550  * @return allocated ReSampleContext, NULL if error occurred
3551  */
3552 ReSampleContext *av_audio_resample_init(int output_channels, int input_channels,
3553                                         int output_rate, int input_rate,
3554                                         enum AVSampleFormat sample_fmt_out,
3555                                         enum AVSampleFormat sample_fmt_in,
3556                                         int filter_length, int log2_phase_count,
3557                                         int linear, double cutoff);
3558 
3559 int audio_resample(ReSampleContext *s, short *output, short *input, int nb_samples);
3560 
3561 /**
3562  * Free resample context.
3563  *
3564  * @param s a non-NULL pointer to a resample context previously
3565  *          created with av_audio_resample_init()
3566  */
3567 void audio_resample_close(ReSampleContext *s);
3568 
3569 
3570 /**
3571  * Initialize an audio resampler.
3572  * Note, if either rate is not an integer then simply scale both rates up so they are.
3573  * @param filter_length length of each FIR filter in the filterbank relative to the cutoff freq
3574  * @param log2_phase_count log2 of the number of entries in the polyphase filterbank
3575  * @param linear If 1 then the used FIR filter will be linearly interpolated
3576                  between the 2 closest, if 0 the closest will be used
3577  * @param cutoff cutoff frequency, 1.0 corresponds to half the output sampling rate
3578  */
3579 struct AVResampleContext *av_resample_init(int out_rate, int in_rate, int filter_length, int log2_phase_count, int linear, double cutoff);
3580 
3581 /**
3582  * Resample an array of samples using a previously configured context.
3583  * @param src an array of unconsumed samples
3584  * @param consumed the number of samples of src which have been consumed are returned here
3585  * @param src_size the number of unconsumed samples available
3586  * @param dst_size the amount of space in samples available in dst
3587  * @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.
3588  * @return the number of samples written in dst or -1 if an error occurred
3589  */
3590 int av_resample(struct AVResampleContext *c, short *dst, short *src, int *consumed, int src_size, int dst_size, int update_ctx);
3591 
3592 
3593 /**
3594  * Compensate samplerate/timestamp drift. The compensation is done by changing
3595  * the resampler parameters, so no audible clicks or similar distortions occur
3596  * @param compensation_distance distance in output samples over which the compensation should be performed
3597  * @param sample_delta number of output samples which should be output less
3598  *
3599  * example: av_resample_compensate(c, 10, 500)
3600  * here instead of 510 samples only 500 samples would be output
3601  *
3602  * note, due to rounding the actual compensation might be slightly different,
3603  * especially if the compensation_distance is large and the in_rate used during init is small
3604  */
3605 void av_resample_compensate(struct AVResampleContext *c, int sample_delta, int compensation_distance);
3606 void av_resample_close(struct AVResampleContext *c);
3607 
3608 /**
3609  * Allocate memory for a picture.  Call avpicture_free() to free it.
3610  *
3611  * @see avpicture_fill()
3612  *
3613  * @param picture the picture to be filled in
3614  * @param pix_fmt the format of the picture
3615  * @param width the width of the picture
3616  * @param height the height of the picture
3617  * @return zero if successful, a negative value if not
3618  */
3619 int avpicture_alloc(AVPicture *picture, enum PixelFormat pix_fmt, int width, int height);
3620 
3621 /**
3622  * Free a picture previously allocated by avpicture_alloc().
3623  * The data buffer used by the AVPicture is freed, but the AVPicture structure
3624  * itself is not.
3625  *
3626  * @param picture the AVPicture to be freed
3627  */
3628 void avpicture_free(AVPicture *picture);
3629 
3630 /**
3631  * Fill in the AVPicture fields.
3632  * The fields of the given AVPicture are filled in by using the 'ptr' address
3633  * which points to the image data buffer. Depending on the specified picture
3634  * format, one or multiple image data pointers and line sizes will be set.
3635  * If a planar format is specified, several pointers will be set pointing to
3636  * the different picture planes and the line sizes of the different planes
3637  * will be stored in the lines_sizes array.
3638  * Call with ptr == NULL to get the required size for the ptr buffer.
3639  *
3640  * To allocate the buffer and fill in the AVPicture fields in one call,
3641  * use avpicture_alloc().
3642  *
3643  * @param picture AVPicture whose fields are to be filled in
3644  * @param ptr Buffer which will contain or contains the actual image data
3645  * @param pix_fmt The format in which the picture data is stored.
3646  * @param width the width of the image in pixels
3647  * @param height the height of the image in pixels
3648  * @return size of the image data in bytes
3649  */
3650 int avpicture_fill(AVPicture *picture, uint8_t *ptr,
3651                    enum PixelFormat pix_fmt, int width, int height);
3652 
3653 /**
3654  * Copy pixel data from an AVPicture into a buffer.
3655  * The data is stored compactly, without any gaps for alignment or padding
3656  * which may be applied by avpicture_fill().
3657  *
3658  * @see avpicture_get_size()
3659  *
3660  * @param[in] src AVPicture containing image data
3661  * @param[in] pix_fmt The format in which the picture data is stored.
3662  * @param[in] width the width of the image in pixels.
3663  * @param[in] height the height of the image in pixels.
3664  * @param[out] dest A buffer into which picture data will be copied.
3665  * @param[in] dest_size The size of 'dest'.
3666  * @return The number of bytes written to dest, or a negative value (error code) on error.
3667  */
3668 int avpicture_layout(const AVPicture* src, enum PixelFormat pix_fmt, int width, int height,
3669                      unsigned char *dest, int dest_size);
3670 
3671 /**
3672  * Calculate the size in bytes that a picture of the given width and height
3673  * would occupy if stored in the given picture format.
3674  * Note that this returns the size of a compact representation as generated
3675  * by avpicture_layout(), which can be smaller than the size required for e.g.
3676  * avpicture_fill().
3677  *
3678  * @param pix_fmt the given picture format
3679  * @param width the width of the image
3680  * @param height the height of the image
3681  * @return Image data size in bytes or -1 on error (e.g. too large dimensions).
3682  */
3683 int avpicture_get_size(enum PixelFormat pix_fmt, int width, int height);
3684 void avcodec_get_chroma_sub_sample(enum PixelFormat pix_fmt, int *h_shift, int *v_shift);
3685 
3686 #if FF_API_GET_PIX_FMT_NAME
3687 /**
3688  * @deprecated Deprecated in favor of av_get_pix_fmt_name().
3689  */
3690 attribute_deprecated
3691 const char *avcodec_get_pix_fmt_name(enum PixelFormat pix_fmt);
3692 #endif
3693 
3694 void avcodec_set_dimensions(AVCodecContext *s, int width, int height);
3695 
3696 /**
3697  * Return a value representing the fourCC code associated to the
3698  * pixel format pix_fmt, or 0 if no associated fourCC code can be
3699  * found.
3700  */
3701 unsigned int avcodec_pix_fmt_to_codec_tag(enum PixelFormat pix_fmt);
3702 
3703 /**
3704  * Put a string representing the codec tag codec_tag in buf.
3705  *
3706  * @param buf_size size in bytes of buf
3707  * @return the length of the string that would have been generated if
3708  * enough space had been available, excluding the trailing null
3709  */
3710 size_t av_get_codec_tag_string(char *buf, size_t buf_size, unsigned int codec_tag);
3711 
3712 #define FF_LOSS_RESOLUTION  0x0001 /**< loss due to resolution change */
3713 #define FF_LOSS_DEPTH       0x0002 /**< loss due to color depth change */
3714 #define FF_LOSS_COLORSPACE  0x0004 /**< loss due to color space conversion */
3715 #define FF_LOSS_ALPHA       0x0008 /**< loss of alpha bits */
3716 #define FF_LOSS_COLORQUANT  0x0010 /**< loss due to color quantization */
3717 #define FF_LOSS_CHROMA      0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
3718 
3719 /**
3720  * Compute what kind of losses will occur when converting from one specific
3721  * pixel format to another.
3722  * When converting from one pixel format to another, information loss may occur.
3723  * For example, when converting from RGB24 to GRAY, the color information will
3724  * be lost. Similarly, other losses occur when converting from some formats to
3725  * other formats. These losses can involve loss of chroma, but also loss of
3726  * resolution, loss of color depth, loss due to the color space conversion, loss
3727  * of the alpha bits or loss due to color quantization.
3728  * avcodec_get_fix_fmt_loss() informs you about the various types of losses
3729  * which will occur when converting from one pixel format to another.
3730  *
3731  * @param[in] dst_pix_fmt destination pixel format
3732  * @param[in] src_pix_fmt source pixel format
3733  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
3734  * @return Combination of flags informing you what kind of losses will occur.
3735  */
3736 int avcodec_get_pix_fmt_loss(enum PixelFormat dst_pix_fmt, enum PixelFormat src_pix_fmt,
3737                              int has_alpha);
3738 
3739 /**
3740  * Find the best pixel format to convert to given a certain source pixel
3741  * format.  When converting from one pixel format to another, information loss
3742  * may occur.  For example, when converting from RGB24 to GRAY, the color
3743  * information will be lost. Similarly, other losses occur when converting from
3744  * some formats to other formats. avcodec_find_best_pix_fmt() searches which of
3745  * the given pixel formats should be used to suffer the least amount of loss.
3746  * The pixel formats from which it chooses one, are determined by the
3747  * pix_fmt_mask parameter.
3748  *
3749  * @code
3750  * src_pix_fmt = PIX_FMT_YUV420P;
3751  * pix_fmt_mask = (1 << PIX_FMT_YUV422P) || (1 << PIX_FMT_RGB24);
3752  * dst_pix_fmt = avcodec_find_best_pix_fmt(pix_fmt_mask, src_pix_fmt, alpha, &loss);
3753  * @endcode
3754  *
3755  * @param[in] pix_fmt_mask bitmask determining which pixel format to choose from
3756  * @param[in] src_pix_fmt source pixel format
3757  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
3758  * @param[out] loss_ptr Combination of flags informing you what kind of losses will occur.
3759  * @return The best pixel format to convert to or -1 if none was found.
3760  */
3761 enum PixelFormat avcodec_find_best_pix_fmt(int64_t pix_fmt_mask, enum PixelFormat src_pix_fmt,
3762                               int has_alpha, int *loss_ptr);
3763 
3764 #if FF_API_GET_ALPHA_INFO
3765 #define FF_ALPHA_TRANSP       0x0001 /* image has some totally transparent pixels */
3766 #define FF_ALPHA_SEMI_TRANSP  0x0002 /* image has some transparent pixels */
3767 
3768 /**
3769  * Tell if an image really has transparent alpha values.
3770  * @return ored mask of FF_ALPHA_xxx constants
3771  */
3772 attribute_deprecated
3773 int img_get_alpha_info(const AVPicture *src,
3774                        enum PixelFormat pix_fmt, int width, int height);
3775 #endif
3776 
3777 /* deinterlace a picture */
3778 /* deinterlace - if not supported return -1 */
3779 int avpicture_deinterlace(AVPicture *dst, const AVPicture *src,
3780                           enum PixelFormat pix_fmt, int width, int height);
3781 
3782 /* external high level API */
3783 
3784 /**
3785  * If c is NULL, returns the first registered codec,
3786  * if c is non-NULL, returns the next registered codec after c,
3787  * or NULL if c is the last one.
3788  */
3789 AVCodec *av_codec_next(AVCodec *c);
3790 
3791 /**
3792  * Return the LIBAVCODEC_VERSION_INT constant.
3793  */
3794 unsigned avcodec_version(void);
3795 
3796 /**
3797  * Return the libavcodec build-time configuration.
3798  */
3799 const char *avcodec_configuration(void);
3800 
3801 /**
3802  * Return the libavcodec license.
3803  */
3804 const char *avcodec_license(void);
3805 
3806 #if FF_API_AVCODEC_INIT
3807 /**
3808  * @deprecated this function is called automatically from avcodec_register()
3809  * and avcodec_register_all(), there is no need to call it manually
3810  */
3811 attribute_deprecated
3812 void avcodec_init(void);
3813 #endif
3814 
3815 /**
3816  * Register the codec codec and initialize libavcodec.
3817  *
3818  * @warning either this function or avcodec_register_all() must be called
3819  * before any other libavcodec functions.
3820  *
3821  * @see avcodec_register_all()
3822  */
3823 void avcodec_register(AVCodec *codec);
3824 
3825 /**
3826  * Find a registered encoder with a matching codec ID.
3827  *
3828  * @param id CodecID of the requested encoder
3829  * @return An encoder if one was found, NULL otherwise.
3830  */
3831 AVCodec *avcodec_find_encoder(enum CodecID id);
3832 
3833 /**
3834  * Find a registered encoder with the specified name.
3835  *
3836  * @param name name of the requested encoder
3837  * @return An encoder if one was found, NULL otherwise.
3838  */
3839 AVCodec *avcodec_find_encoder_by_name(const char *name);
3840 
3841 /**
3842  * Find a registered decoder with a matching codec ID.
3843  *
3844  * @param id CodecID of the requested decoder
3845  * @return A decoder if one was found, NULL otherwise.
3846  */
3847 AVCodec *avcodec_find_decoder(enum CodecID id);
3848 
3849 /**
3850  * Find a registered decoder with the specified name.
3851  *
3852  * @param name name of the requested decoder
3853  * @return A decoder if one was found, NULL otherwise.
3854  */
3855 AVCodec *avcodec_find_decoder_by_name(const char *name);
3856 void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode);
3857 
3858 /**
3859  * Return a name for the specified profile, if available.
3860  *
3861  * @param codec the codec that is searched for the given profile
3862  * @param profile the profile value for which a name is requested
3863  * @return A name for the profile if found, NULL otherwise.
3864  */
3865 const char *av_get_profile_name(const AVCodec *codec, int profile);
3866 
3867 #if FF_API_ALLOC_CONTEXT
3868 /**
3869  * Set the fields of the given AVCodecContext to default values.
3870  *
3871  * @param s The AVCodecContext of which the fields should be set to default values.
3872  * @deprecated use avcodec_get_context_defaults3
3873  */
3874 attribute_deprecated
3875 void avcodec_get_context_defaults(AVCodecContext *s);
3876 
3877 /** THIS FUNCTION IS NOT YET PART OF THE PUBLIC API!
3878  *  we WILL change its arguments and name a few times! */
3879 attribute_deprecated
3880 void avcodec_get_context_defaults2(AVCodecContext *s, enum AVMediaType);
3881 #endif
3882 
3883 /**
3884  * Set the fields of the given AVCodecContext to default values corresponding
3885  * to the given codec (defaults may be codec-dependent).
3886  *
3887  * Do not call this function if a non-NULL codec has been passed
3888  * to avcodec_alloc_context3() that allocated this AVCodecContext.
3889  * If codec is non-NULL, it is illegal to call avcodec_open2() with a
3890  * different codec on this AVCodecContext.
3891  */
3892 int avcodec_get_context_defaults3(AVCodecContext *s, AVCodec *codec);
3893 
3894 #if FF_API_ALLOC_CONTEXT
3895 /**
3896  * Allocate an AVCodecContext and set its fields to default values.  The
3897  * resulting struct can be deallocated by simply calling av_free().
3898  *
3899  * @return An AVCodecContext filled with default values or NULL on failure.
3900  * @see avcodec_get_context_defaults
3901  *
3902  * @deprecated use avcodec_alloc_context3()
3903  */
3904 attribute_deprecated
3905 AVCodecContext *avcodec_alloc_context(void);
3906 
3907 /** THIS FUNCTION IS NOT YET PART OF THE PUBLIC API!
3908  *  we WILL change its arguments and name a few times! */
3909 attribute_deprecated
3910 AVCodecContext *avcodec_alloc_context2(enum AVMediaType);
3911 #endif
3912 
3913 /**
3914  * Allocate an AVCodecContext and set its fields to default values.  The
3915  * resulting struct can be deallocated by calling avcodec_close() on it followed
3916  * by av_free().
3917  *
3918  * @param codec if non-NULL, allocate private data and initialize defaults
3919  *              for the given codec. It is illegal to then call avcodec_open2()
3920  *              with a different codec.
3921  *
3922  * @return An AVCodecContext filled with default values or NULL on failure.
3923  * @see avcodec_get_context_defaults
3924  */
3925 AVCodecContext *avcodec_alloc_context3(AVCodec *codec);
3926 
3927 /**
3928  * Copy the settings of the source AVCodecContext into the destination
3929  * AVCodecContext. The resulting destination codec context will be
3930  * unopened, i.e. you are required to call avcodec_open2() before you
3931  * can use this AVCodecContext to decode/encode video/audio data.
3932  *
3933  * @param dest target codec context, should be initialized with
3934  *             avcodec_alloc_context3(), but otherwise uninitialized
3935  * @param src source codec context
3936  * @return AVERROR() on error (e.g. memory allocation error), 0 on success
3937  */
3938 int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src);
3939 
3940 /**
3941  * Set the fields of the given AVFrame to default values.
3942  *
3943  * @param pic The AVFrame of which the fields should be set to default values.
3944  */
3945 void avcodec_get_frame_defaults(AVFrame *pic);
3946 
3947 /**
3948  * Allocate an AVFrame and set its fields to default values.  The resulting
3949  * struct can be deallocated by simply calling av_free().
3950  *
3951  * @return An AVFrame filled with default values or NULL on failure.
3952  * @see avcodec_get_frame_defaults
3953  */
3954 AVFrame *avcodec_alloc_frame(void);
3955 
3956 int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic);
3957 void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic);
3958 int avcodec_default_reget_buffer(AVCodecContext *s, AVFrame *pic);
3959 
3960 /**
3961  * Return the amount of padding in pixels which the get_buffer callback must
3962  * provide around the edge of the image for codecs which do not have the
3963  * CODEC_FLAG_EMU_EDGE flag.
3964  *
3965  * @return Required padding in pixels.
3966  */
3967 unsigned avcodec_get_edge_width(void);
3968 /**
3969  * Modify width and height values so that they will result in a memory
3970  * buffer that is acceptable for the codec if you do not use any horizontal
3971  * padding.
3972  *
3973  * May only be used if a codec with CODEC_CAP_DR1 has been opened.
3974  * If CODEC_FLAG_EMU_EDGE is not set, the dimensions must have been increased
3975  * according to avcodec_get_edge_width() before.
3976  */
3977 void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height);
3978 /**
3979  * Modify width and height values so that they will result in a memory
3980  * buffer that is acceptable for the codec if you also ensure that all
3981  * line sizes are a multiple of the respective linesize_align[i].
3982  *
3983  * May only be used if a codec with CODEC_CAP_DR1 has been opened.
3984  * If CODEC_FLAG_EMU_EDGE is not set, the dimensions must have been increased
3985  * according to avcodec_get_edge_width() before.
3986  */
3987 void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
3988                                int linesize_align[AV_NUM_DATA_POINTERS]);
3989 
3990 enum PixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum PixelFormat * fmt);
3991 
3992 #if FF_API_THREAD_INIT
3993 /**
3994  * @deprecated Set s->thread_count before calling avcodec_open2() instead of calling this.
3995  */
3996 attribute_deprecated
3997 int avcodec_thread_init(AVCodecContext *s, int thread_count);
3998 #endif
3999 
4000 int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size);
4001 int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2, int, int),void *arg, int *ret, int count);
4002 //FIXME func typedef
4003 
4004 #if FF_API_AVCODEC_OPEN
4005 /**
4006  * Initialize the AVCodecContext to use the given AVCodec. Prior to using this
4007  * function the context has to be allocated.
4008  *
4009  * The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
4010  * avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
4011  * retrieving a codec.
4012  *
4013  * @warning This function is not thread safe!
4014  *
4015  * @code
4016  * avcodec_register_all();
4017  * codec = avcodec_find_decoder(CODEC_ID_H264);
4018  * if (!codec)
4019  *     exit(1);
4020  *
4021  * context = avcodec_alloc_context3(codec);
4022  *
4023  * if (avcodec_open(context, codec) < 0)
4024  *     exit(1);
4025  * @endcode
4026  *
4027  * @param avctx The context which will be set up to use the given codec.
4028  * @param codec The codec to use within the context.
4029  * @return zero on success, a negative value on error
4030  * @see avcodec_alloc_context3, avcodec_find_decoder, avcodec_find_encoder, avcodec_close
4031  *
4032  * @deprecated use avcodec_open2
4033  */
4034 attribute_deprecated
4035 int avcodec_open(AVCodecContext *avctx, AVCodec *codec);
4036 #endif
4037 
4038 /**
4039  * Initialize the AVCodecContext to use the given AVCodec. Prior to using this
4040  * function the context has to be allocated with avcodec_alloc_context3().
4041  *
4042  * The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
4043  * avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
4044  * retrieving a codec.
4045  *
4046  * @warning This function is not thread safe!
4047  *
4048  * @code
4049  * avcodec_register_all();
4050  * av_dict_set(&opts, "b", "2.5M", 0);
4051  * codec = avcodec_find_decoder(CODEC_ID_H264);
4052  * if (!codec)
4053  *     exit(1);
4054  *
4055  * context = avcodec_alloc_context3(codec);
4056  *
4057  * if (avcodec_open2(context, codec, opts) < 0)
4058  *     exit(1);
4059  * @endcode
4060  *
4061  * @param avctx The context to initialize.
4062  * @param codec The codec to open this context for. If a non-NULL codec has been
4063  *              previously passed to avcodec_alloc_context3() or
4064  *              avcodec_get_context_defaults3() for this context, then this
4065  *              parameter MUST be either NULL or equal to the previously passed
4066  *              codec.
4067  * @param options A dictionary filled with AVCodecContext and codec-private options.
4068  *                On return this object will be filled with options that were not found.
4069  *
4070  * @return zero on success, a negative value on error
4071  * @see avcodec_alloc_context3(), avcodec_find_decoder(), avcodec_find_encoder(),
4072  *      av_dict_set(), av_opt_find().
4073  */
4074 int avcodec_open2(AVCodecContext *avctx, AVCodec *codec, AVDictionary **options);
4075 
4076 #if FF_API_OLD_DECODE_AUDIO
4077 /**
4078  * Wrapper function which calls avcodec_decode_audio4.
4079  *
4080  * @deprecated Use avcodec_decode_audio4 instead.
4081  *
4082  * Decode the audio frame of size avpkt->size from avpkt->data into samples.
4083  * Some decoders may support multiple frames in a single AVPacket, such
4084  * decoders would then just decode the first frame. In this case,
4085  * avcodec_decode_audio3 has to be called again with an AVPacket that contains
4086  * the remaining data in order to decode the second frame etc.
4087  * If no frame
4088  * could be outputted, frame_size_ptr is zero. Otherwise, it is the
4089  * decompressed frame size in bytes.
4090  *
4091  * @warning You must set frame_size_ptr to the allocated size of the
4092  * output buffer before calling avcodec_decode_audio3().
4093  *
4094  * @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
4095  * the actual read bytes because some optimized bitstream readers read 32 or 64
4096  * bits at once and could read over the end.
4097  *
4098  * @warning The end of the input buffer avpkt->data should be set to 0 to ensure that
4099  * no overreading happens for damaged MPEG streams.
4100  *
4101  * @warning You must not provide a custom get_buffer() when using
4102  * avcodec_decode_audio3().  Doing so will override it with
4103  * avcodec_default_get_buffer.  Use avcodec_decode_audio4() instead,
4104  * which does allow the application to provide a custom get_buffer().
4105  *
4106  * @note You might have to align the input buffer avpkt->data and output buffer
4107  * samples. The alignment requirements depend on the CPU: On some CPUs it isn't
4108  * necessary at all, on others it won't work at all if not aligned and on others
4109  * it will work but it will have an impact on performance.
4110  *
4111  * In practice, avpkt->data should have 4 byte alignment at minimum and
4112  * samples should be 16 byte aligned unless the CPU doesn't need it
4113  * (AltiVec and SSE do).
4114  *
4115  * @note Codecs which have the CODEC_CAP_DELAY capability set have a delay
4116  * between input and output, these need to be fed with avpkt->data=NULL,
4117  * avpkt->size=0 at the end to return the remaining frames.
4118  *
4119  * @param avctx the codec context
4120  * @param[out] samples the output buffer, sample type in avctx->sample_fmt
4121  *                     If the sample format is planar, each channel plane will
4122  *                     be the same size, with no padding between channels.
4123  * @param[in,out] frame_size_ptr the output buffer size in bytes
4124  * @param[in] avpkt The input AVPacket containing the input buffer.
4125  *            You can create such packet with av_init_packet() and by then setting
4126  *            data and size, some decoders might in addition need other fields.
4127  *            All decoders are designed to use the least fields possible though.
4128  * @return On error a negative value is returned, otherwise the number of bytes
4129  * used or zero if no frame data was decompressed (used) from the input AVPacket.
4130  */
4131 attribute_deprecated int avcodec_decode_audio3(AVCodecContext *avctx, int16_t *samples,
4132                          int *frame_size_ptr,
4133                          AVPacket *avpkt);
4134 #endif
4135 
4136 /**
4137  * Decode the audio frame of size avpkt->size from avpkt->data into frame.
4138  *
4139  * Some decoders may support multiple frames in a single AVPacket. Such
4140  * decoders would then just decode the first frame. In this case,
4141  * avcodec_decode_audio4 has to be called again with an AVPacket containing
4142  * the remaining data in order to decode the second frame, etc...
4143  * Even if no frames are returned, the packet needs to be fed to the decoder
4144  * with remaining data until it is completely consumed or an error occurs.
4145  *
4146  * @warning The input buffer, avpkt->data must be FF_INPUT_BUFFER_PADDING_SIZE
4147  *          larger than the actual read bytes because some optimized bitstream
4148  *          readers read 32 or 64 bits at once and could read over the end.
4149  *
4150  * @note You might have to align the input buffer. The alignment requirements
4151  *       depend on the CPU and the decoder.
4152  *
4153  * @param      avctx the codec context
4154  * @param[out] frame The AVFrame in which to store decoded audio samples.
4155  *                   Decoders request a buffer of a particular size by setting
4156  *                   AVFrame.nb_samples prior to calling get_buffer(). The
4157  *                   decoder may, however, only utilize part of the buffer by
4158  *                   setting AVFrame.nb_samples to a smaller value in the
4159  *                   output frame.
4160  * @param[out] got_frame_ptr Zero if no frame could be decoded, otherwise it is
4161  *                           non-zero.
4162  * @param[in]  avpkt The input AVPacket containing the input buffer.
4163  *                   At least avpkt->data and avpkt->size should be set. Some
4164  *                   decoders might also require additional fields to be set.
4165  * @return A negative error code is returned if an error occurred during
4166  *         decoding, otherwise the number of bytes consumed from the input
4167  *         AVPacket is returned.
4168  */
4169 int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame *frame,
4170                           int *got_frame_ptr, AVPacket *avpkt);
4171 
4172 /**
4173  * Decode the video frame of size avpkt->size from avpkt->data into picture.
4174  * Some decoders may support multiple frames in a single AVPacket, such
4175  * decoders would then just decode the first frame.
4176  *
4177  * @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
4178  * the actual read bytes because some optimized bitstream readers read 32 or 64
4179  * bits at once and could read over the end.
4180  *
4181  * @warning The end of the input buffer buf should be set to 0 to ensure that
4182  * no overreading happens for damaged MPEG streams.
4183  *
4184  * @note You might have to align the input buffer avpkt->data.
4185  * The alignment requirements depend on the CPU: on some CPUs it isn't
4186  * necessary at all, on others it won't work at all if not aligned and on others
4187  * it will work but it will have an impact on performance.
4188  *
4189  * In practice, avpkt->data should have 4 byte alignment at minimum.
4190  *
4191  * @note Codecs which have the CODEC_CAP_DELAY capability set have a delay
4192  * between input and output, these need to be fed with avpkt->data=NULL,
4193  * avpkt->size=0 at the end to return the remaining frames.
4194  *
4195  * @param avctx the codec context
4196  * @param[out] picture The AVFrame in which the decoded video frame will be stored.
4197  *             Use avcodec_alloc_frame to get an AVFrame, the codec will
4198  *             allocate memory for the actual bitmap.
4199  *             with default get/release_buffer(), the decoder frees/reuses the bitmap as it sees fit.
4200  *             with overridden get/release_buffer() (needs CODEC_CAP_DR1) the user decides into what buffer the decoder
4201  *                   decodes and the decoder tells the user once it does not need the data anymore,
4202  *                   the user app can at this point free/reuse/keep the memory as it sees fit.
4203  *
4204  * @param[in] avpkt The input AVpacket containing the input buffer.
4205  *            You can create such packet with av_init_packet() and by then setting
4206  *            data and size, some decoders might in addition need other fields like
4207  *            flags&AV_PKT_FLAG_KEY. All decoders are designed to use the least
4208  *            fields possible.
4209  * @param[in,out] got_picture_ptr Zero if no frame could be decompressed, otherwise, it is nonzero.
4210  * @return On error a negative value is returned, otherwise the number of bytes
4211  * used or zero if no frame could be decompressed.
4212  */
4213 int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
4214                          int *got_picture_ptr,
4215                          AVPacket *avpkt);
4216 
4217 /**
4218  * Decode a subtitle message.
4219  * Return a negative value on error, otherwise return the number of bytes used.
4220  * If no subtitle could be decompressed, got_sub_ptr is zero.
4221  * Otherwise, the subtitle is stored in *sub.
4222  * Note that CODEC_CAP_DR1 is not available for subtitle codecs. This is for
4223  * simplicity, because the performance difference is expect to be negligible
4224  * and reusing a get_buffer written for video codecs would probably perform badly
4225  * due to a potentially very different allocation pattern.
4226  *
4227  * @param avctx the codec context
4228  * @param[out] sub The AVSubtitle in which the decoded subtitle will be stored, must be
4229                    freed with avsubtitle_free if *got_sub_ptr is set.
4230  * @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
4231  * @param[in] avpkt The input AVPacket containing the input buffer.
4232  */
4233 int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
4234                             int *got_sub_ptr,
4235                             AVPacket *avpkt);
4236 
4237 /**
4238  * Free all allocated data in the given subtitle struct.
4239  *
4240  * @param sub AVSubtitle to free.
4241  */
4242 void avsubtitle_free(AVSubtitle *sub);
4243 
4244 #if FF_API_OLD_ENCODE_AUDIO
4245 /**
4246  * Encode an audio frame from samples into buf.
4247  *
4248  * @deprecated Use avcodec_encode_audio2 instead.
4249  *
4250  * @note The output buffer should be at least FF_MIN_BUFFER_SIZE bytes large.
4251  * However, for codecs with avctx->frame_size equal to 0 (e.g. PCM) the user
4252  * will know how much space is needed because it depends on the value passed
4253  * in buf_size as described below. In that case a lower value can be used.
4254  *
4255  * @param avctx the codec context
4256  * @param[out] buf the output buffer
4257  * @param[in] buf_size the output buffer size
4258  * @param[in] samples the input buffer containing the samples
4259  * The number of samples read from this buffer is frame_size*channels,
4260  * both of which are defined in avctx.
4261  * For codecs which have avctx->frame_size equal to 0 (e.g. PCM) the number of
4262  * samples read from samples is equal to:
4263  * buf_size * 8 / (avctx->channels * av_get_bits_per_sample(avctx->codec_id))
4264  * This also implies that av_get_bits_per_sample() must not return 0 for these
4265  * codecs.
4266  * @return On error a negative value is returned, on success zero or the number
4267  * of bytes used to encode the data read from the input buffer.
4268  */
4269 int attribute_deprecated avcodec_encode_audio(AVCodecContext *avctx,
4270                                               uint8_t *buf, int buf_size,
4271                                               const short *samples);
4272 #endif
4273 
4274 /**
4275  * Encode a frame of audio.
4276  *
4277  * Takes input samples from frame and writes the next output packet, if
4278  * available, to avpkt. The output packet does not necessarily contain data for
4279  * the most recent frame, as encoders can delay, split, and combine input frames
4280  * internally as needed.
4281  *
4282  * @param avctx     codec context
4283  * @param avpkt     output AVPacket.
4284  *                  The user can supply an output buffer by setting
4285  *                  avpkt->data and avpkt->size prior to calling the
4286  *                  function, but if the size of the user-provided data is not
4287  *                  large enough, encoding will fail. All other AVPacket fields
4288  *                  will be reset by the encoder using av_init_packet(). If
4289  *                  avpkt->data is NULL, the encoder will allocate it.
4290  *                  The encoder will set avpkt->size to the size of the
4291  *                  output packet.
4292  * @param[in] frame AVFrame containing the raw audio data to be encoded.
4293  *                  May be NULL when flushing an encoder that has the
4294  *                  CODEC_CAP_DELAY capability set.
4295  *                  There are 2 codec capabilities that affect the allowed
4296  *                  values of frame->nb_samples.
4297  *                  If CODEC_CAP_SMALL_LAST_FRAME is set, then only the final
4298  *                  frame may be smaller than avctx->frame_size, and all other
4299  *                  frames must be equal to avctx->frame_size.
4300  *                  If CODEC_CAP_VARIABLE_FRAME_SIZE is set, then each frame
4301  *                  can have any number of samples.
4302  *                  If neither is set, frame->nb_samples must be equal to
4303  *                  avctx->frame_size for all frames.
4304  * @param[out] got_packet_ptr This field is set to 1 by libavcodec if the
4305  *                            output packet is non-empty, and to 0 if it is
4306  *                            empty. If the function returns an error, the
4307  *                            packet can be assumed to be invalid, and the
4308  *                            value of got_packet_ptr is undefined and should
4309  *                            not be used.
4310  * @return          0 on success, negative error code on failure
4311  */
4312 int avcodec_encode_audio2(AVCodecContext *avctx, AVPacket *avpkt,
4313                           const AVFrame *frame, int *got_packet_ptr);
4314 
4315 /**
4316  * Fill audio frame data and linesize.
4317  * AVFrame extended_data channel pointers are allocated if necessary for
4318  * planar audio.
4319  *
4320  * @param frame       the AVFrame
4321  *                    frame->nb_samples must be set prior to calling the
4322  *                    function. This function fills in frame->data,
4323  *                    frame->extended_data, frame->linesize[0].
4324  * @param nb_channels channel count
4325  * @param sample_fmt  sample format
4326  * @param buf         buffer to use for frame data
4327  * @param buf_size    size of buffer
4328  * @param align       plane size sample alignment
4329  * @return            0 on success, negative error code on failure
4330  */
4331 int avcodec_fill_audio_frame(AVFrame *frame, int nb_channels,
4332                              enum AVSampleFormat sample_fmt, const uint8_t *buf,
4333                              int buf_size, int align);
4334 
4335 /**
4336  * Encode a video frame from pict into buf.
4337  * The input picture should be
4338  * stored using a specific format, namely avctx.pix_fmt.
4339  *
4340  * @param avctx the codec context
4341  * @param[out] buf the output buffer for the bitstream of encoded frame
4342  * @param[in] buf_size the size of the output buffer in bytes
4343  * @param[in] pict the input picture to encode
4344  * @return On error a negative value is returned, on success zero or the number
4345  * of bytes used from the output buffer.
4346  */
4347 int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size,
4348                          const AVFrame *pict);
4349 int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
4350                             const AVSubtitle *sub);
4351 
4352 /**
4353  * Close a given AVCodecContext and free all the data associated with it
4354  * (but not the AVCodecContext itself).
4355  *
4356  * Calling this function on an AVCodecContext that hasn't been opened will free
4357  * the codec-specific data allocated in avcodec_alloc_context3() /
4358  * avcodec_get_context_defaults3() with a non-NULL codec. Subsequent calls will
4359  * do nothing.
4360  */
4361 int avcodec_close(AVCodecContext *avctx);
4362 
4363 /**
4364  * Register all the codecs, parsers and bitstream filters which were enabled at
4365  * configuration time. If you do not call this function you can select exactly
4366  * which formats you want to support, by using the individual registration
4367  * functions.
4368  *
4369  * @see avcodec_register
4370  * @see av_register_codec_parser
4371  * @see av_register_bitstream_filter
4372  */
4373 void avcodec_register_all(void);
4374 
4375 /**
4376  * Flush buffers, should be called when seeking or when switching to a different stream.
4377  */
4378 void avcodec_flush_buffers(AVCodecContext *avctx);
4379 
4380 void avcodec_default_free_buffers(AVCodecContext *s);
4381 
4382 /* misc useful functions */
4383 
4384 #if FF_API_OLD_FF_PICT_TYPES
4385 /**
4386  * Return a single letter to describe the given picture type pict_type.
4387  *
4388  * @param[in] pict_type the picture type
4389  * @return A single character representing the picture type.
4390  * @deprecated Use av_get_picture_type_char() instead.
4391  */
4392 attribute_deprecated
4393 char av_get_pict_type_char(int pict_type);
4394 #endif
4395 
4396 /**
4397  * Return codec bits per sample.
4398  *
4399  * @param[in] codec_id the codec
4400  * @return Number of bits per sample or zero if unknown for the given codec.
4401  */
4402 int av_get_bits_per_sample(enum CodecID codec_id);
4403 
4404 #if FF_API_OLD_SAMPLE_FMT
4405 /**
4406  * @deprecated Use av_get_bytes_per_sample() instead.
4407  */
4408 attribute_deprecated
4409 int av_get_bits_per_sample_format(enum AVSampleFormat sample_fmt);
4410 #endif
4411 
4412 /* frame parsing */
4413 typedef struct AVCodecParserContext {
4414     void *priv_data;
4415     struct AVCodecParser *parser;
4416     int64_t frame_offset; /* offset of the current frame */
4417     int64_t cur_offset; /* current offset
4418                            (incremented by each av_parser_parse()) */
4419     int64_t next_frame_offset; /* offset of the next frame */
4420     /* video info */
4421     int pict_type; /* XXX: Put it back in AVCodecContext. */
4422     /**
4423      * This field is used for proper frame duration computation in lavf.
4424      * It signals, how much longer the frame duration of the current frame
4425      * is compared to normal frame duration.
4426      *
4427      * frame_duration = (1 + repeat_pict) * time_base
4428      *
4429      * It is used by codecs like H.264 to display telecined material.
4430      */
4431     int repeat_pict; /* XXX: Put it back in AVCodecContext. */
4432     int64_t pts;     /* pts of the current frame */
4433     int64_t dts;     /* dts of the current frame */
4434 
4435     /* private data */
4436     int64_t last_pts;
4437     int64_t last_dts;
4438     int fetch_timestamp;
4439 
4440 #define AV_PARSER_PTS_NB 4
4441     int cur_frame_start_index;
4442     int64_t cur_frame_offset[AV_PARSER_PTS_NB];
4443     int64_t cur_frame_pts[AV_PARSER_PTS_NB];
4444     int64_t cur_frame_dts[AV_PARSER_PTS_NB];
4445 
4446     int flags;
4447 #define PARSER_FLAG_COMPLETE_FRAMES           0x0001
4448 #define PARSER_FLAG_ONCE                      0x0002
4449 /// Set if the parser has a valid file offset
4450 #define PARSER_FLAG_FETCHED_OFFSET            0x0004
4451 
4452     int64_t offset;      ///< byte offset from starting packet start
4453     int64_t cur_frame_end[AV_PARSER_PTS_NB];
4454 
4455     /**
4456      * Set by parser to 1 for key frames and 0 for non-key frames.
4457      * It is initialized to -1, so if the parser doesn't set this flag,
4458      * old-style fallback using AV_PICTURE_TYPE_I picture type as key frames
4459      * will be used.
4460      */
4461     int key_frame;
4462 
4463     /**
4464      * Time difference in stream time base units from the pts of this
4465      * packet to the point at which the output from the decoder has converged
4466      * independent from the availability of previous frames. That is, the
4467      * frames are virtually identical no matter if decoding started from
4468      * the very first frame or from this keyframe.
4469      * Is AV_NOPTS_VALUE if unknown.
4470      * This field is not the display duration of the current frame.
4471      * This field has no meaning if the packet does not have AV_PKT_FLAG_KEY
4472      * set.
4473      *
4474      * The purpose of this field is to allow seeking in streams that have no
4475      * keyframes in the conventional sense. It corresponds to the
4476      * recovery point SEI in H.264 and match_time_delta in NUT. It is also
4477      * essential for some types of subtitle streams to ensure that all
4478      * subtitles are correctly displayed after seeking.
4479      */
4480     int64_t convergence_duration;
4481 
4482     // Timestamp generation support:
4483     /**
4484      * Synchronization point for start of timestamp generation.
4485      *
4486      * Set to >0 for sync point, 0 for no sync point and <0 for undefined
4487      * (default).
4488      *
4489      * For example, this corresponds to presence of H.264 buffering period
4490      * SEI message.
4491      */
4492     int dts_sync_point;
4493 
4494     /**
4495      * Offset of the current timestamp against last timestamp sync point in
4496      * units of AVCodecContext.time_base.
4497      *
4498      * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
4499      * contain a valid timestamp offset.
4500      *
4501      * Note that the timestamp of sync point has usually a nonzero
4502      * dts_ref_dts_delta, which refers to the previous sync point. Offset of
4503      * the next frame after timestamp sync point will be usually 1.
4504      *
4505      * For example, this corresponds to H.264 cpb_removal_delay.
4506      */
4507     int dts_ref_dts_delta;
4508 
4509     /**
4510      * Presentation delay of current frame in units of AVCodecContext.time_base.
4511      *
4512      * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
4513      * contain valid non-negative timestamp delta (presentation time of a frame
4514      * must not lie in the past).
4515      *
4516      * This delay represents the difference between decoding and presentation
4517      * time of the frame.
4518      *
4519      * For example, this corresponds to H.264 dpb_output_delay.
4520      */
4521     int pts_dts_delta;
4522 
4523     /**
4524      * Position of the packet in file.
4525      *
4526      * Analogous to cur_frame_pts/dts
4527      */
4528     int64_t cur_frame_pos[AV_PARSER_PTS_NB];
4529 
4530     /**
4531      * Byte position of currently parsed frame in stream.
4532      */
4533     int64_t pos;
4534 
4535     /**
4536      * Previous frame byte position.
4537      */
4538     int64_t last_pos;
4539 } AVCodecParserContext;
4540 
4541 typedef struct AVCodecParser {
4542     int codec_ids[5]; /* several codec IDs are permitted */
4543     int priv_data_size;
4544     int (*parser_init)(AVCodecParserContext *s);
4545     int (*parser_parse)(AVCodecParserContext *s,
4546                         AVCodecContext *avctx,
4547                         const uint8_t **poutbuf, int *poutbuf_size,
4548                         const uint8_t *buf, int buf_size);
4549     void (*parser_close)(AVCodecParserContext *s);
4550     int (*split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
4551     struct AVCodecParser *next;
4552 } AVCodecParser;
4553 
4554 AVCodecParser *av_parser_next(AVCodecParser *c);
4555 
4556 void av_register_codec_parser(AVCodecParser *parser);
4557 AVCodecParserContext *av_parser_init(int codec_id);
4558 
4559 /**
4560  * Parse a packet.
4561  *
4562  * @param s             parser context.
4563  * @param avctx         codec context.
4564  * @param poutbuf       set to pointer to parsed buffer or NULL if not yet finished.
4565  * @param poutbuf_size  set to size of parsed buffer or zero if not yet finished.
4566  * @param buf           input buffer.
4567  * @param buf_size      input length, to signal EOF, this should be 0 (so that the last frame can be output).
4568  * @param pts           input presentation timestamp.
4569  * @param dts           input decoding timestamp.
4570  * @param pos           input byte position in stream.
4571  * @return the number of bytes of the input bitstream used.
4572  *
4573  * Example:
4574  * @code
4575  *   while(in_len){
4576  *       len = av_parser_parse2(myparser, AVCodecContext, &data, &size,
4577  *                                        in_data, in_len,
4578  *                                        pts, dts, pos);
4579  *       in_data += len;
4580  *       in_len  -= len;
4581  *
4582  *       if(size)
4583  *          decode_frame(data, size);
4584  *   }
4585  * @endcode
4586  */
4587 int av_parser_parse2(AVCodecParserContext *s,
4588                      AVCodecContext *avctx,
4589                      uint8_t **poutbuf, int *poutbuf_size,
4590                      const uint8_t *buf, int buf_size,
4591                      int64_t pts, int64_t dts,
4592                      int64_t pos);
4593 
4594 int av_parser_change(AVCodecParserContext *s,
4595                      AVCodecContext *avctx,
4596                      uint8_t **poutbuf, int *poutbuf_size,
4597                      const uint8_t *buf, int buf_size, int keyframe);
4598 void av_parser_close(AVCodecParserContext *s);
4599 
4600 
4601 typedef struct AVBitStreamFilterContext {
4602     void *priv_data;
4603     struct AVBitStreamFilter *filter;
4604     AVCodecParserContext *parser;
4605     struct AVBitStreamFilterContext *next;
4606 } AVBitStreamFilterContext;
4607 
4608 
4609 typedef struct AVBitStreamFilter {
4610     const char *name;
4611     int priv_data_size;
4612     int (*filter)(AVBitStreamFilterContext *bsfc,
4613                   AVCodecContext *avctx, const char *args,
4614                   uint8_t **poutbuf, int *poutbuf_size,
4615                   const uint8_t *buf, int buf_size, int keyframe);
4616     void (*close)(AVBitStreamFilterContext *bsfc);
4617     struct AVBitStreamFilter *next;
4618 } AVBitStreamFilter;
4619 
4620 void av_register_bitstream_filter(AVBitStreamFilter *bsf);
4621 AVBitStreamFilterContext *av_bitstream_filter_init(const char *name);
4622 int av_bitstream_filter_filter(AVBitStreamFilterContext *bsfc,
4623                                AVCodecContext *avctx, const char *args,
4624                                uint8_t **poutbuf, int *poutbuf_size,
4625                                const uint8_t *buf, int buf_size, int keyframe);
4626 void av_bitstream_filter_close(AVBitStreamFilterContext *bsf);
4627 
4628 AVBitStreamFilter *av_bitstream_filter_next(AVBitStreamFilter *f);
4629 
4630 /* memory */
4631 
4632 /**
4633  * Reallocate the given block if it is not large enough, otherwise do nothing.
4634  *
4635  * @see av_realloc
4636  */
4637 void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size);
4638 
4639 /**
4640  * Allocate a buffer, reusing the given one if large enough.
4641  *
4642  * Contrary to av_fast_realloc the current buffer contents might not be
4643  * preserved and on error the old buffer is freed, thus no special
4644  * handling to avoid memleaks is necessary.
4645  *
4646  * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer
4647  * @param size size of the buffer *ptr points to
4648  * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and
4649  *                 *size 0 if an error occurred.
4650  */
4651 void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size);
4652 
4653 /**
4654  * Copy image src to dst. Wraps av_picture_data_copy() above.
4655  */
4656 void av_picture_copy(AVPicture *dst, const AVPicture *src,
4657                      enum PixelFormat pix_fmt, int width, int height);
4658 
4659 /**
4660  * Crop image top and left side.
4661  */
4662 int av_picture_crop(AVPicture *dst, const AVPicture *src,
4663                     enum PixelFormat pix_fmt, int top_band, int left_band);
4664 
4665 /**
4666  * Pad image.
4667  */
4668 int av_picture_pad(AVPicture *dst, const AVPicture *src, int height, int width, enum PixelFormat pix_fmt,
4669             int padtop, int padbottom, int padleft, int padright, int *color);
4670 
4671 /**
4672  * Encode extradata length to a buffer. Used by xiph codecs.
4673  *
4674  * @param s buffer to write to; must be at least (v/255+1) bytes long
4675  * @param v size of extradata in bytes
4676  * @return number of bytes written to the buffer.
4677  */
4678 unsigned int av_xiphlacing(unsigned char *s, unsigned int v);
4679 
4680 /**
4681  * Log a generic warning message about a missing feature. This function is
4682  * intended to be used internally by Libav (libavcodec, libavformat, etc.)
4683  * only, and would normally not be used by applications.
4684  * @param[in] avc a pointer to an arbitrary struct of which the first field is
4685  * a pointer to an AVClass struct
4686  * @param[in] feature string containing the name of the missing feature
4687  * @param[in] want_sample indicates if samples are wanted which exhibit this feature.
4688  * If want_sample is non-zero, additional verbage will be added to the log
4689  * message which tells the user how to report samples to the development
4690  * mailing list.
4691  */
4692 void av_log_missing_feature(void *avc, const char *feature, int want_sample);
4693 
4694 /**
4695  * Log a generic warning message asking for a sample. This function is
4696  * intended to be used internally by Libav (libavcodec, libavformat, etc.)
4697  * only, and would normally not be used by applications.
4698  * @param[in] avc a pointer to an arbitrary struct of which the first field is
4699  * a pointer to an AVClass struct
4700  * @param[in] msg string containing an optional message, or NULL if no message
4701  */
4702 void av_log_ask_for_sample(void *avc, const char *msg, ...) av_printf_format(2, 3);
4703 
4704 /**
4705  * Register the hardware accelerator hwaccel.
4706  */
4707 void av_register_hwaccel(AVHWAccel *hwaccel);
4708 
4709 /**
4710  * If hwaccel is NULL, returns the first registered hardware accelerator,
4711  * if hwaccel is non-NULL, returns the next registered hardware accelerator
4712  * after hwaccel, or NULL if hwaccel is the last one.
4713  */
4714 AVHWAccel *av_hwaccel_next(AVHWAccel *hwaccel);
4715 
4716 
4717 /**
4718  * Lock operation used by lockmgr
4719  */
4720 enum AVLockOp {
4721   AV_LOCK_CREATE,  ///< Create a mutex
4722   AV_LOCK_OBTAIN,  ///< Lock the mutex
4723   AV_LOCK_RELEASE, ///< Unlock the mutex
4724   AV_LOCK_DESTROY, ///< Free mutex resources
4725 };
4726 
4727 /**
4728  * Register a user provided lock manager supporting the operations
4729  * specified by AVLockOp. mutex points to a (void *) where the
4730  * lockmgr should store/get a pointer to a user allocated mutex. It's
4731  * NULL upon AV_LOCK_CREATE and != NULL for all other ops.
4732  *
4733  * @param cb User defined callback. Note: Libav may invoke calls to this
4734  *           callback during the call to av_lockmgr_register().
4735  *           Thus, the application must be prepared to handle that.
4736  *           If cb is set to NULL the lockmgr will be unregistered.
4737  *           Also note that during unregistration the previously registered
4738  *           lockmgr callback may also be invoked.
4739  */
4740 int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op));
4741 
4742 /**
4743  * Get the type of the given codec.
4744  */
4745 enum AVMediaType avcodec_get_type(enum CodecID codec_id);
4746 
4747 /**
4748  * Get the AVClass for AVCodecContext. It can be used in combination with
4749  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
4750  *
4751  * @see av_opt_find().
4752  */
4753 const AVClass *avcodec_get_class(void);
4754 
4755 /**
4756  * @return a positive value if s is open (i.e. avcodec_open2() was called on it
4757  * with no corresponding avcodec_close()), 0 otherwise.
4758  */
4759 int avcodec_is_open(AVCodecContext *s);
4760 
4761 #endif /* AVCODEC_AVCODEC_H */
4762