1 /*
2  * QDM2 compatible decoder
3  * Copyright (c) 2003 Ewald Snel
4  * Copyright (c) 2005 Benjamin Larsson
5  * Copyright (c) 2005 Alex Beregszaszi
6  * Copyright (c) 2005 Roberto Togni
7  *
8  * This file is part of FFmpeg.
9  *
10  * FFmpeg is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * FFmpeg is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with FFmpeg; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 /**
26  * @file
27  * QDM2 decoder
28  * @author Ewald Snel, Benjamin Larsson, Alex Beregszaszi, Roberto Togni
29  *
30  * The decoder is not perfect yet, there are still some distortions
31  * especially on files encoded with 16 or 8 subbands.
32  */
33 
34 #include <math.h>
35 #include <stddef.h>
36 #include <stdio.h>
37 
38 #include "libavutil/channel_layout.h"
39 
40 #define BITSTREAM_READER_LE
41 #include "avcodec.h"
42 #include "get_bits.h"
43 #include "bytestream.h"
44 #include "internal.h"
45 #include "mpegaudio.h"
46 #include "mpegaudiodsp.h"
47 #include "rdft.h"
48 
49 #include "qdm2_tablegen.h"
50 
51 #define QDM2_LIST_ADD(list, size, packet) \
52 do { \
53       if (size > 0) { \
54     list[size - 1].next = &list[size]; \
55       } \
56       list[size].packet = packet; \
57       list[size].next = NULL; \
58       size++; \
59 } while(0)
60 
61 // Result is 8, 16 or 30
62 #define QDM2_SB_USED(sub_sampling) (((sub_sampling) >= 2) ? 30 : 8 << (sub_sampling))
63 
64 #define FIX_NOISE_IDX(noise_idx) \
65   if ((noise_idx) >= 3840) \
66     (noise_idx) -= 3840; \
67 
68 #define SB_DITHERING_NOISE(sb,noise_idx) (noise_table[(noise_idx)++] * sb_noise_attenuation[(sb)])
69 
70 #define SAMPLES_NEEDED \
71      av_log (NULL,AV_LOG_INFO,"This file triggers some untested code. Please contact the developers.\n");
72 
73 #define SAMPLES_NEEDED_2(why) \
74      av_log (NULL,AV_LOG_INFO,"This file triggers some missing code. Please contact the developers.\nPosition: %s\n",why);
75 
76 #define QDM2_MAX_FRAME_SIZE 512
77 
78 typedef int8_t sb_int8_array[2][30][64];
79 
80 /**
81  * Subpacket
82  */
83 typedef struct QDM2SubPacket {
84     int type;            ///< subpacket type
85     unsigned int size;   ///< subpacket size
86     const uint8_t *data; ///< pointer to subpacket data (points to input data buffer, it's not a private copy)
87 } QDM2SubPacket;
88 
89 /**
90  * A node in the subpacket list
91  */
92 typedef struct QDM2SubPNode {
93     QDM2SubPacket *packet;      ///< packet
94     struct QDM2SubPNode *next; ///< pointer to next packet in the list, NULL if leaf node
95 } QDM2SubPNode;
96 
97 typedef struct QDM2Complex {
98     float re;
99     float im;
100 } QDM2Complex;
101 
102 typedef struct FFTTone {
103     float level;
104     QDM2Complex *complex;
105     const float *table;
106     int   phase;
107     int   phase_shift;
108     int   duration;
109     short time_index;
110     short cutoff;
111 } FFTTone;
112 
113 typedef struct FFTCoefficient {
114     int16_t sub_packet;
115     uint8_t channel;
116     int16_t offset;
117     int16_t exp;
118     uint8_t phase;
119 } FFTCoefficient;
120 
121 typedef struct QDM2FFT {
122     DECLARE_ALIGNED(32, QDM2Complex, complex)[MPA_MAX_CHANNELS][256];
123 } QDM2FFT;
124 
125 /**
126  * QDM2 decoder context
127  */
128 typedef struct QDM2Context {
129     /// Parameters from codec header, do not change during playback
130     int nb_channels;         ///< number of channels
131     int channels;            ///< number of channels
132     int group_size;          ///< size of frame group (16 frames per group)
133     int fft_size;            ///< size of FFT, in complex numbers
134     int checksum_size;       ///< size of data block, used also for checksum
135 
136     /// Parameters built from header parameters, do not change during playback
137     int group_order;         ///< order of frame group
138     int fft_order;           ///< order of FFT (actually fftorder+1)
139     int frame_size;          ///< size of data frame
140     int frequency_range;
141     int sub_sampling;        ///< subsampling: 0=25%, 1=50%, 2=100% */
142     int coeff_per_sb_select; ///< selector for "num. of coeffs. per subband" tables. Can be 0, 1, 2
143     int cm_table_select;     ///< selector for "coding method" tables. Can be 0, 1 (from init: 0-4)
144 
145     /// Packets and packet lists
146     QDM2SubPacket sub_packets[16];      ///< the packets themselves
147     QDM2SubPNode sub_packet_list_A[16]; ///< list of all packets
148     QDM2SubPNode sub_packet_list_B[16]; ///< FFT packets B are on list
149     int sub_packets_B;                  ///< number of packets on 'B' list
150     QDM2SubPNode sub_packet_list_C[16]; ///< packets with errors?
151     QDM2SubPNode sub_packet_list_D[16]; ///< DCT packets
152 
153     /// FFT and tones
154     FFTTone fft_tones[1000];
155     int fft_tone_start;
156     int fft_tone_end;
157     FFTCoefficient fft_coefs[1000];
158     int fft_coefs_index;
159     int fft_coefs_min_index[5];
160     int fft_coefs_max_index[5];
161     int fft_level_exp[6];
162     RDFTContext rdft_ctx;
163     QDM2FFT fft;
164 
165     /// I/O data
166     const uint8_t *compressed_data;
167     int compressed_size;
168     float output_buffer[QDM2_MAX_FRAME_SIZE * MPA_MAX_CHANNELS * 2];
169 
170     /// Synthesis filter
171     MPADSPContext mpadsp;
172     DECLARE_ALIGNED(32, float, synth_buf)[MPA_MAX_CHANNELS][512*2];
173     int synth_buf_offset[MPA_MAX_CHANNELS];
174     DECLARE_ALIGNED(32, float, sb_samples)[MPA_MAX_CHANNELS][128][SBLIMIT];
175     DECLARE_ALIGNED(32, float, samples)[MPA_MAX_CHANNELS * MPA_FRAME_SIZE];
176 
177     /// Mixed temporary data used in decoding
178     float tone_level[MPA_MAX_CHANNELS][30][64];
179     int8_t coding_method[MPA_MAX_CHANNELS][30][64];
180     int8_t quantized_coeffs[MPA_MAX_CHANNELS][10][8];
181     int8_t tone_level_idx_base[MPA_MAX_CHANNELS][30][8];
182     int8_t tone_level_idx_hi1[MPA_MAX_CHANNELS][3][8][8];
183     int8_t tone_level_idx_mid[MPA_MAX_CHANNELS][26][8];
184     int8_t tone_level_idx_hi2[MPA_MAX_CHANNELS][26];
185     int8_t tone_level_idx[MPA_MAX_CHANNELS][30][64];
186     int8_t tone_level_idx_temp[MPA_MAX_CHANNELS][30][64];
187 
188     // Flags
189     int has_errors;         ///< packet has errors
190     int superblocktype_2_3; ///< select fft tables and some algorithm based on superblock type
191     int do_synth_filter;    ///< used to perform or skip synthesis filter
192 
193     int sub_packet;
194     int noise_idx; ///< index for dithering noise table
195 } QDM2Context;
196 
197 static const int switchtable[23] = {
198     0, 5, 1, 5, 5, 5, 5, 5, 2, 5, 5, 5, 5, 5, 5, 5, 3, 5, 5, 5, 5, 5, 4
199 };
200 
qdm2_get_vlc(GetBitContext * gb,const VLC * vlc,int flag,int depth)201 static int qdm2_get_vlc(GetBitContext *gb, const VLC *vlc, int flag, int depth)
202 {
203     int value;
204 
205     value = get_vlc2(gb, vlc->table, vlc->bits, depth);
206 
207     /* stage-2, 3 bits exponent escape sequence */
208     if (value-- == 0)
209         value = get_bits(gb, get_bits(gb, 3) + 1);
210 
211     /* stage-3, optional */
212     if (flag) {
213         int tmp;
214 
215         if (value >= 60) {
216             av_log(NULL, AV_LOG_ERROR, "value %d in qdm2_get_vlc too large\n", value);
217             return 0;
218         }
219 
220         tmp= vlc_stage3_values[value];
221 
222         if ((value & ~3) > 0)
223             tmp += get_bits(gb, (value >> 2));
224         value = tmp;
225     }
226 
227     return value;
228 }
229 
qdm2_get_se_vlc(const VLC * vlc,GetBitContext * gb,int depth)230 static int qdm2_get_se_vlc(const VLC *vlc, GetBitContext *gb, int depth)
231 {
232     int value = qdm2_get_vlc(gb, vlc, 0, depth);
233 
234     return (value & 1) ? ((value + 1) >> 1) : -(value >> 1);
235 }
236 
237 /**
238  * QDM2 checksum
239  *
240  * @param data      pointer to data to be checksummed
241  * @param length    data length
242  * @param value     checksum value
243  *
244  * @return          0 if checksum is OK
245  */
qdm2_packet_checksum(const uint8_t * data,int length,int value)246 static uint16_t qdm2_packet_checksum(const uint8_t *data, int length, int value)
247 {
248     int i;
249 
250     for (i = 0; i < length; i++)
251         value -= data[i];
252 
253     return (uint16_t)(value & 0xffff);
254 }
255 
256 /**
257  * Fill a QDM2SubPacket structure with packet type, size, and data pointer.
258  *
259  * @param gb            bitreader context
260  * @param sub_packet    packet under analysis
261  */
qdm2_decode_sub_packet_header(GetBitContext * gb,QDM2SubPacket * sub_packet)262 static void qdm2_decode_sub_packet_header(GetBitContext *gb,
263                                           QDM2SubPacket *sub_packet)
264 {
265     sub_packet->type = get_bits(gb, 8);
266 
267     if (sub_packet->type == 0) {
268         sub_packet->size = 0;
269         sub_packet->data = NULL;
270     } else {
271         sub_packet->size = get_bits(gb, 8);
272 
273         if (sub_packet->type & 0x80) {
274             sub_packet->size <<= 8;
275             sub_packet->size  |= get_bits(gb, 8);
276             sub_packet->type  &= 0x7f;
277         }
278 
279         if (sub_packet->type == 0x7f)
280             sub_packet->type |= (get_bits(gb, 8) << 8);
281 
282         // FIXME: this depends on bitreader-internal data
283         sub_packet->data = &gb->buffer[get_bits_count(gb) / 8];
284     }
285 
286     av_log(NULL, AV_LOG_DEBUG, "Subpacket: type=%d size=%d start_offs=%x\n",
287            sub_packet->type, sub_packet->size, get_bits_count(gb) / 8);
288 }
289 
290 /**
291  * Return node pointer to first packet of requested type in list.
292  *
293  * @param list    list of subpackets to be scanned
294  * @param type    type of searched subpacket
295  * @return        node pointer for subpacket if found, else NULL
296  */
qdm2_search_subpacket_type_in_list(QDM2SubPNode * list,int type)297 static QDM2SubPNode *qdm2_search_subpacket_type_in_list(QDM2SubPNode *list,
298                                                         int type)
299 {
300     while (list && list->packet) {
301         if (list->packet->type == type)
302             return list;
303         list = list->next;
304     }
305     return NULL;
306 }
307 
308 /**
309  * Replace 8 elements with their average value.
310  * Called by qdm2_decode_superblock before starting subblock decoding.
311  *
312  * @param q       context
313  */
average_quantized_coeffs(QDM2Context * q)314 static void average_quantized_coeffs(QDM2Context *q)
315 {
316     int i, j, n, ch, sum;
317 
318     n = coeff_per_sb_for_avg[q->coeff_per_sb_select][QDM2_SB_USED(q->sub_sampling) - 1] + 1;
319 
320     for (ch = 0; ch < q->nb_channels; ch++)
321         for (i = 0; i < n; i++) {
322             sum = 0;
323 
324             for (j = 0; j < 8; j++)
325                 sum += q->quantized_coeffs[ch][i][j];
326 
327             sum /= 8;
328             if (sum > 0)
329                 sum--;
330 
331             for (j = 0; j < 8; j++)
332                 q->quantized_coeffs[ch][i][j] = sum;
333         }
334 }
335 
336 /**
337  * Build subband samples with noise weighted by q->tone_level.
338  * Called by synthfilt_build_sb_samples.
339  *
340  * @param q     context
341  * @param sb    subband index
342  */
build_sb_samples_from_noise(QDM2Context * q,int sb)343 static void build_sb_samples_from_noise(QDM2Context *q, int sb)
344 {
345     int ch, j;
346 
347     FIX_NOISE_IDX(q->noise_idx);
348 
349     if (!q->nb_channels)
350         return;
351 
352     for (ch = 0; ch < q->nb_channels; ch++) {
353         for (j = 0; j < 64; j++) {
354             q->sb_samples[ch][j * 2][sb] =
355                 SB_DITHERING_NOISE(sb, q->noise_idx) * q->tone_level[ch][sb][j];
356             q->sb_samples[ch][j * 2 + 1][sb] =
357                 SB_DITHERING_NOISE(sb, q->noise_idx) * q->tone_level[ch][sb][j];
358         }
359     }
360 }
361 
362 /**
363  * Called while processing data from subpackets 11 and 12.
364  * Used after making changes to coding_method array.
365  *
366  * @param sb               subband index
367  * @param channels         number of channels
368  * @param coding_method    q->coding_method[0][0][0]
369  */
fix_coding_method_array(int sb,int channels,sb_int8_array coding_method)370 static int fix_coding_method_array(int sb, int channels,
371                                    sb_int8_array coding_method)
372 {
373     int j, k;
374     int ch;
375     int run, case_val;
376 
377     for (ch = 0; ch < channels; ch++) {
378         for (j = 0; j < 64; ) {
379             if (coding_method[ch][sb][j] < 8)
380                 return -1;
381             if ((coding_method[ch][sb][j] - 8) > 22) {
382                 run      = 1;
383                 case_val = 8;
384             } else {
385                 switch (switchtable[coding_method[ch][sb][j] - 8]) {
386                 case 0: run  = 10;
387                     case_val = 10;
388                     break;
389                 case 1: run  = 1;
390                     case_val = 16;
391                     break;
392                 case 2: run  = 5;
393                     case_val = 24;
394                     break;
395                 case 3: run  = 3;
396                     case_val = 30;
397                     break;
398                 case 4: run  = 1;
399                     case_val = 30;
400                     break;
401                 case 5: run  = 1;
402                     case_val = 8;
403                     break;
404                 default: run = 1;
405                     case_val = 8;
406                     break;
407                 }
408             }
409             for (k = 0; k < run; k++) {
410                 if (j + k < 128) {
411                     if (coding_method[ch][sb + (j + k) / 64][(j + k) % 64] > coding_method[ch][sb][j]) {
412                         if (k > 0) {
413                             SAMPLES_NEEDED
414                             //not debugged, almost never used
415                             memset(&coding_method[ch][sb][j + k], case_val,
416                                    k *sizeof(int8_t));
417                             memset(&coding_method[ch][sb][j + k], case_val,
418                                    3 * sizeof(int8_t));
419                         }
420                     }
421                 }
422             }
423             j += run;
424         }
425     }
426     return 0;
427 }
428 
429 /**
430  * Related to synthesis filter
431  * Called by process_subpacket_10
432  *
433  * @param q       context
434  * @param flag    1 if called after getting data from subpacket 10, 0 if no subpacket 10
435  */
fill_tone_level_array(QDM2Context * q,int flag)436 static void fill_tone_level_array(QDM2Context *q, int flag)
437 {
438     int i, sb, ch, sb_used;
439     int tmp, tab;
440 
441     for (ch = 0; ch < q->nb_channels; ch++)
442         for (sb = 0; sb < 30; sb++)
443             for (i = 0; i < 8; i++) {
444                 if ((tab=coeff_per_sb_for_dequant[q->coeff_per_sb_select][sb]) < (last_coeff[q->coeff_per_sb_select] - 1))
445                     tmp = q->quantized_coeffs[ch][tab + 1][i] * dequant_table[q->coeff_per_sb_select][tab + 1][sb]+
446                           q->quantized_coeffs[ch][tab][i] * dequant_table[q->coeff_per_sb_select][tab][sb];
447                 else
448                     tmp = q->quantized_coeffs[ch][tab][i] * dequant_table[q->coeff_per_sb_select][tab][sb];
449                 if(tmp < 0)
450                     tmp += 0xff;
451                 q->tone_level_idx_base[ch][sb][i] = (tmp / 256) & 0xff;
452             }
453 
454     sb_used = QDM2_SB_USED(q->sub_sampling);
455 
456     if ((q->superblocktype_2_3 != 0) && !flag) {
457         for (sb = 0; sb < sb_used; sb++)
458             for (ch = 0; ch < q->nb_channels; ch++)
459                 for (i = 0; i < 64; i++) {
460                     q->tone_level_idx[ch][sb][i] = q->tone_level_idx_base[ch][sb][i / 8];
461                     if (q->tone_level_idx[ch][sb][i] < 0)
462                         q->tone_level[ch][sb][i] = 0;
463                     else
464                         q->tone_level[ch][sb][i] = fft_tone_level_table[0][q->tone_level_idx[ch][sb][i] & 0x3f];
465                 }
466     } else {
467         tab = q->superblocktype_2_3 ? 0 : 1;
468         for (sb = 0; sb < sb_used; sb++) {
469             if ((sb >= 4) && (sb <= 23)) {
470                 for (ch = 0; ch < q->nb_channels; ch++)
471                     for (i = 0; i < 64; i++) {
472                         tmp = q->tone_level_idx_base[ch][sb][i / 8] -
473                               q->tone_level_idx_hi1[ch][sb / 8][i / 8][i % 8] -
474                               q->tone_level_idx_mid[ch][sb - 4][i / 8] -
475                               q->tone_level_idx_hi2[ch][sb - 4];
476                         q->tone_level_idx[ch][sb][i] = tmp & 0xff;
477                         if ((tmp < 0) || (!q->superblocktype_2_3 && !tmp))
478                             q->tone_level[ch][sb][i] = 0;
479                         else
480                             q->tone_level[ch][sb][i] = fft_tone_level_table[tab][tmp & 0x3f];
481                 }
482             } else {
483                 if (sb > 4) {
484                     for (ch = 0; ch < q->nb_channels; ch++)
485                         for (i = 0; i < 64; i++) {
486                             tmp = q->tone_level_idx_base[ch][sb][i / 8] -
487                                   q->tone_level_idx_hi1[ch][2][i / 8][i % 8] -
488                                   q->tone_level_idx_hi2[ch][sb - 4];
489                             q->tone_level_idx[ch][sb][i] = tmp & 0xff;
490                             if ((tmp < 0) || (!q->superblocktype_2_3 && !tmp))
491                                 q->tone_level[ch][sb][i] = 0;
492                             else
493                                 q->tone_level[ch][sb][i] = fft_tone_level_table[tab][tmp & 0x3f];
494                     }
495                 } else {
496                     for (ch = 0; ch < q->nb_channels; ch++)
497                         for (i = 0; i < 64; i++) {
498                             tmp = q->tone_level_idx[ch][sb][i] = q->tone_level_idx_base[ch][sb][i / 8];
499                             if ((tmp < 0) || (!q->superblocktype_2_3 && !tmp))
500                                 q->tone_level[ch][sb][i] = 0;
501                             else
502                                 q->tone_level[ch][sb][i] = fft_tone_level_table[tab][tmp & 0x3f];
503                         }
504                 }
505             }
506         }
507     }
508 }
509 
510 /**
511  * Related to synthesis filter
512  * Called by process_subpacket_11
513  * c is built with data from subpacket 11
514  * Most of this function is used only if superblock_type_2_3 == 0,
515  * never seen it in samples.
516  *
517  * @param tone_level_idx
518  * @param tone_level_idx_temp
519  * @param coding_method        q->coding_method[0][0][0]
520  * @param nb_channels          number of channels
521  * @param c                    coming from subpacket 11, passed as 8*c
522  * @param superblocktype_2_3   flag based on superblock packet type
523  * @param cm_table_select      q->cm_table_select
524  */
fill_coding_method_array(sb_int8_array tone_level_idx,sb_int8_array tone_level_idx_temp,sb_int8_array coding_method,int nb_channels,int c,int superblocktype_2_3,int cm_table_select)525 static void fill_coding_method_array(sb_int8_array tone_level_idx,
526                                      sb_int8_array tone_level_idx_temp,
527                                      sb_int8_array coding_method,
528                                      int nb_channels,
529                                      int c, int superblocktype_2_3,
530                                      int cm_table_select)
531 {
532     int ch, sb, j;
533     int tmp, acc, esp_40, comp;
534     int add1, add2, add3, add4;
535     int64_t multres;
536 
537     if (!superblocktype_2_3) {
538         /* This case is untested, no samples available */
539         avpriv_request_sample(NULL, "!superblocktype_2_3");
540         return;
541         for (ch = 0; ch < nb_channels; ch++) {
542             for (sb = 0; sb < 30; sb++) {
543                 for (j = 1; j < 63; j++) {  // The loop only iterates to 63 so the code doesn't overflow the buffer
544                     add1 = tone_level_idx[ch][sb][j] - 10;
545                     if (add1 < 0)
546                         add1 = 0;
547                     add2 = add3 = add4 = 0;
548                     if (sb > 1) {
549                         add2 = tone_level_idx[ch][sb - 2][j] + tone_level_idx_offset_table[sb][0] - 6;
550                         if (add2 < 0)
551                             add2 = 0;
552                     }
553                     if (sb > 0) {
554                         add3 = tone_level_idx[ch][sb - 1][j] + tone_level_idx_offset_table[sb][1] - 6;
555                         if (add3 < 0)
556                             add3 = 0;
557                     }
558                     if (sb < 29) {
559                         add4 = tone_level_idx[ch][sb + 1][j] + tone_level_idx_offset_table[sb][3] - 6;
560                         if (add4 < 0)
561                             add4 = 0;
562                     }
563                     tmp = tone_level_idx[ch][sb][j + 1] * 2 - add4 - add3 - add2 - add1;
564                     if (tmp < 0)
565                         tmp = 0;
566                     tone_level_idx_temp[ch][sb][j + 1] = tmp & 0xff;
567                 }
568                 tone_level_idx_temp[ch][sb][0] = tone_level_idx_temp[ch][sb][1];
569             }
570         }
571         acc = 0;
572         for (ch = 0; ch < nb_channels; ch++)
573             for (sb = 0; sb < 30; sb++)
574                 for (j = 0; j < 64; j++)
575                     acc += tone_level_idx_temp[ch][sb][j];
576 
577         multres = 0x66666667LL * (acc * 10);
578         esp_40 = (multres >> 32) / 8 + ((multres & 0xffffffff) >> 31);
579         for (ch = 0;  ch < nb_channels; ch++)
580             for (sb = 0; sb < 30; sb++)
581                 for (j = 0; j < 64; j++) {
582                     comp = tone_level_idx_temp[ch][sb][j]* esp_40 * 10;
583                     if (comp < 0)
584                         comp += 0xff;
585                     comp /= 256; // signed shift
586                     switch(sb) {
587                         case 0:
588                             if (comp < 30)
589                                 comp = 30;
590                             comp += 15;
591                             break;
592                         case 1:
593                             if (comp < 24)
594                                 comp = 24;
595                             comp += 10;
596                             break;
597                         case 2:
598                         case 3:
599                         case 4:
600                             if (comp < 16)
601                                 comp = 16;
602                     }
603                     if (comp <= 5)
604                         tmp = 0;
605                     else if (comp <= 10)
606                         tmp = 10;
607                     else if (comp <= 16)
608                         tmp = 16;
609                     else if (comp <= 24)
610                         tmp = -1;
611                     else
612                         tmp = 0;
613                     coding_method[ch][sb][j] = ((tmp & 0xfffa) + 30 )& 0xff;
614                 }
615         for (sb = 0; sb < 30; sb++)
616             fix_coding_method_array(sb, nb_channels, coding_method);
617         for (ch = 0; ch < nb_channels; ch++)
618             for (sb = 0; sb < 30; sb++)
619                 for (j = 0; j < 64; j++)
620                     if (sb >= 10) {
621                         if (coding_method[ch][sb][j] < 10)
622                             coding_method[ch][sb][j] = 10;
623                     } else {
624                         if (sb >= 2) {
625                             if (coding_method[ch][sb][j] < 16)
626                                 coding_method[ch][sb][j] = 16;
627                         } else {
628                             if (coding_method[ch][sb][j] < 30)
629                                 coding_method[ch][sb][j] = 30;
630                         }
631                     }
632     } else { // superblocktype_2_3 != 0
633         for (ch = 0; ch < nb_channels; ch++)
634             for (sb = 0; sb < 30; sb++)
635                 for (j = 0; j < 64; j++)
636                     coding_method[ch][sb][j] = coding_method_table[cm_table_select][sb];
637     }
638 }
639 
640 /**
641  * Called by process_subpacket_11 to process more data from subpacket 11
642  * with sb 0-8.
643  * Called by process_subpacket_12 to process data from subpacket 12 with
644  * sb 8-sb_used.
645  *
646  * @param q         context
647  * @param gb        bitreader context
648  * @param length    packet length in bits
649  * @param sb_min    lower subband processed (sb_min included)
650  * @param sb_max    higher subband processed (sb_max excluded)
651  */
synthfilt_build_sb_samples(QDM2Context * q,GetBitContext * gb,int length,int sb_min,int sb_max)652 static int synthfilt_build_sb_samples(QDM2Context *q, GetBitContext *gb,
653                                        int length, int sb_min, int sb_max)
654 {
655     int sb, j, k, n, ch, run, channels;
656     int joined_stereo, zero_encoding;
657     int type34_first;
658     float type34_div = 0;
659     float type34_predictor;
660     float samples[10];
661     int sign_bits[16] = {0};
662 
663     if (length == 0) {
664         // If no data use noise
665         for (sb=sb_min; sb < sb_max; sb++)
666             build_sb_samples_from_noise(q, sb);
667 
668         return 0;
669     }
670 
671     for (sb = sb_min; sb < sb_max; sb++) {
672         channels = q->nb_channels;
673 
674         if (q->nb_channels <= 1 || sb < 12)
675             joined_stereo = 0;
676         else if (sb >= 24)
677             joined_stereo = 1;
678         else
679             joined_stereo = (get_bits_left(gb) >= 1) ? get_bits1(gb) : 0;
680 
681         if (joined_stereo) {
682             if (get_bits_left(gb) >= 16)
683                 for (j = 0; j < 16; j++)
684                     sign_bits[j] = get_bits1(gb);
685 
686             for (j = 0; j < 64; j++)
687                 if (q->coding_method[1][sb][j] > q->coding_method[0][sb][j])
688                     q->coding_method[0][sb][j] = q->coding_method[1][sb][j];
689 
690             if (fix_coding_method_array(sb, q->nb_channels,
691                                             q->coding_method)) {
692                 av_log(NULL, AV_LOG_ERROR, "coding method invalid\n");
693                 build_sb_samples_from_noise(q, sb);
694                 continue;
695             }
696             channels = 1;
697         }
698 
699         for (ch = 0; ch < channels; ch++) {
700             FIX_NOISE_IDX(q->noise_idx);
701             zero_encoding = (get_bits_left(gb) >= 1) ? get_bits1(gb) : 0;
702             type34_predictor = 0.0;
703             type34_first = 1;
704 
705             for (j = 0; j < 128; ) {
706                 switch (q->coding_method[ch][sb][j / 2]) {
707                     case 8:
708                         if (get_bits_left(gb) >= 10) {
709                             if (zero_encoding) {
710                                 for (k = 0; k < 5; k++) {
711                                     if ((j + 2 * k) >= 128)
712                                         break;
713                                     samples[2 * k] = get_bits1(gb) ? dequant_1bit[joined_stereo][2 * get_bits1(gb)] : 0;
714                                 }
715                             } else {
716                                 n = get_bits(gb, 8);
717                                 if (n >= 243) {
718                                     av_log(NULL, AV_LOG_ERROR, "Invalid 8bit codeword\n");
719                                     return AVERROR_INVALIDDATA;
720                                 }
721 
722                                 for (k = 0; k < 5; k++)
723                                     samples[2 * k] = dequant_1bit[joined_stereo][random_dequant_index[n][k]];
724                             }
725                             for (k = 0; k < 5; k++)
726                                 samples[2 * k + 1] = SB_DITHERING_NOISE(sb,q->noise_idx);
727                         } else {
728                             for (k = 0; k < 10; k++)
729                                 samples[k] = SB_DITHERING_NOISE(sb,q->noise_idx);
730                         }
731                         run = 10;
732                         break;
733 
734                     case 10:
735                         if (get_bits_left(gb) >= 1) {
736                             float f = 0.81;
737 
738                             if (get_bits1(gb))
739                                 f = -f;
740                             f -= noise_samples[((sb + 1) * (j +5 * ch + 1)) & 127] * 9.0 / 40.0;
741                             samples[0] = f;
742                         } else {
743                             samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);
744                         }
745                         run = 1;
746                         break;
747 
748                     case 16:
749                         if (get_bits_left(gb) >= 10) {
750                             if (zero_encoding) {
751                                 for (k = 0; k < 5; k++) {
752                                     if ((j + k) >= 128)
753                                         break;
754                                     samples[k] = (get_bits1(gb) == 0) ? 0 : dequant_1bit[joined_stereo][2 * get_bits1(gb)];
755                                 }
756                             } else {
757                                 n = get_bits (gb, 8);
758                                 if (n >= 243) {
759                                     av_log(NULL, AV_LOG_ERROR, "Invalid 8bit codeword\n");
760                                     return AVERROR_INVALIDDATA;
761                                 }
762 
763                                 for (k = 0; k < 5; k++)
764                                     samples[k] = dequant_1bit[joined_stereo][random_dequant_index[n][k]];
765                             }
766                         } else {
767                             for (k = 0; k < 5; k++)
768                                 samples[k] = SB_DITHERING_NOISE(sb,q->noise_idx);
769                         }
770                         run = 5;
771                         break;
772 
773                     case 24:
774                         if (get_bits_left(gb) >= 7) {
775                             n = get_bits(gb, 7);
776                             if (n >= 125) {
777                                 av_log(NULL, AV_LOG_ERROR, "Invalid 7bit codeword\n");
778                                 return AVERROR_INVALIDDATA;
779                             }
780 
781                             for (k = 0; k < 3; k++)
782                                 samples[k] = (random_dequant_type24[n][k] - 2.0) * 0.5;
783                         } else {
784                             for (k = 0; k < 3; k++)
785                                 samples[k] = SB_DITHERING_NOISE(sb,q->noise_idx);
786                         }
787                         run = 3;
788                         break;
789 
790                     case 30:
791                         if (get_bits_left(gb) >= 4) {
792                             unsigned index = qdm2_get_vlc(gb, &vlc_tab_type30, 0, 1);
793                             if (index >= FF_ARRAY_ELEMS(type30_dequant)) {
794                                 av_log(NULL, AV_LOG_ERROR, "index %d out of type30_dequant array\n", index);
795                                 return AVERROR_INVALIDDATA;
796                             }
797                             samples[0] = type30_dequant[index];
798                         } else
799                             samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);
800 
801                         run = 1;
802                         break;
803 
804                     case 34:
805                         if (get_bits_left(gb) >= 7) {
806                             if (type34_first) {
807                                 type34_div = (float)(1 << get_bits(gb, 2));
808                                 samples[0] = ((float)get_bits(gb, 5) - 16.0) / 15.0;
809                                 type34_predictor = samples[0];
810                                 type34_first = 0;
811                             } else {
812                                 unsigned index = qdm2_get_vlc(gb, &vlc_tab_type34, 0, 1);
813                                 if (index >= FF_ARRAY_ELEMS(type34_delta)) {
814                                     av_log(NULL, AV_LOG_ERROR, "index %d out of type34_delta array\n", index);
815                                     return AVERROR_INVALIDDATA;
816                                 }
817                                 samples[0] = type34_delta[index] / type34_div + type34_predictor;
818                                 type34_predictor = samples[0];
819                             }
820                         } else {
821                             samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);
822                         }
823                         run = 1;
824                         break;
825 
826                     default:
827                         samples[0] = SB_DITHERING_NOISE(sb,q->noise_idx);
828                         run = 1;
829                         break;
830                 }
831 
832                 if (joined_stereo) {
833                     for (k = 0; k < run && j + k < 128; k++) {
834                         q->sb_samples[0][j + k][sb] =
835                             q->tone_level[0][sb][(j + k) / 2] * samples[k];
836                         if (q->nb_channels == 2) {
837                             if (sign_bits[(j + k) / 8])
838                                 q->sb_samples[1][j + k][sb] =
839                                     q->tone_level[1][sb][(j + k) / 2] * -samples[k];
840                             else
841                                 q->sb_samples[1][j + k][sb] =
842                                     q->tone_level[1][sb][(j + k) / 2] * samples[k];
843                         }
844                     }
845                 } else {
846                     for (k = 0; k < run; k++)
847                         if ((j + k) < 128)
848                             q->sb_samples[ch][j + k][sb] = q->tone_level[ch][sb][(j + k)/2] * samples[k];
849                 }
850 
851                 j += run;
852             } // j loop
853         } // channel loop
854     } // subband loop
855     return 0;
856 }
857 
858 /**
859  * Init the first element of a channel in quantized_coeffs with data
860  * from packet 10 (quantized_coeffs[ch][0]).
861  * This is similar to process_subpacket_9, but for a single channel
862  * and for element [0]
863  * same VLC tables as process_subpacket_9 are used.
864  *
865  * @param quantized_coeffs    pointer to quantized_coeffs[ch][0]
866  * @param gb        bitreader context
867  */
init_quantized_coeffs_elem0(int8_t * quantized_coeffs,GetBitContext * gb)868 static int init_quantized_coeffs_elem0(int8_t *quantized_coeffs,
869                                         GetBitContext *gb)
870 {
871     int i, k, run, level, diff;
872 
873     if (get_bits_left(gb) < 16)
874         return -1;
875     level = qdm2_get_vlc(gb, &vlc_tab_level, 0, 2);
876 
877     quantized_coeffs[0] = level;
878 
879     for (i = 0; i < 7; ) {
880         if (get_bits_left(gb) < 16)
881             return -1;
882         run = qdm2_get_vlc(gb, &vlc_tab_run, 0, 1) + 1;
883 
884         if (i + run >= 8)
885             return -1;
886 
887         if (get_bits_left(gb) < 16)
888             return -1;
889         diff = qdm2_get_se_vlc(&vlc_tab_diff, gb, 2);
890 
891         for (k = 1; k <= run; k++)
892             quantized_coeffs[i + k] = (level + ((k * diff) / run));
893 
894         level += diff;
895         i += run;
896     }
897     return 0;
898 }
899 
900 /**
901  * Related to synthesis filter, process data from packet 10
902  * Init part of quantized_coeffs via function init_quantized_coeffs_elem0
903  * Init tone_level_idx_hi1, tone_level_idx_hi2, tone_level_idx_mid with
904  * data from packet 10
905  *
906  * @param q         context
907  * @param gb        bitreader context
908  */
init_tone_level_dequantization(QDM2Context * q,GetBitContext * gb)909 static void init_tone_level_dequantization(QDM2Context *q, GetBitContext *gb)
910 {
911     int sb, j, k, n, ch;
912 
913     for (ch = 0; ch < q->nb_channels; ch++) {
914         init_quantized_coeffs_elem0(q->quantized_coeffs[ch][0], gb);
915 
916         if (get_bits_left(gb) < 16) {
917             memset(q->quantized_coeffs[ch][0], 0, 8);
918             break;
919         }
920     }
921 
922     n = q->sub_sampling + 1;
923 
924     for (sb = 0; sb < n; sb++)
925         for (ch = 0; ch < q->nb_channels; ch++)
926             for (j = 0; j < 8; j++) {
927                 if (get_bits_left(gb) < 1)
928                     break;
929                 if (get_bits1(gb)) {
930                     for (k=0; k < 8; k++) {
931                         if (get_bits_left(gb) < 16)
932                             break;
933                         q->tone_level_idx_hi1[ch][sb][j][k] = qdm2_get_vlc(gb, &vlc_tab_tone_level_idx_hi1, 0, 2);
934                     }
935                 } else {
936                     for (k=0; k < 8; k++)
937                         q->tone_level_idx_hi1[ch][sb][j][k] = 0;
938                 }
939             }
940 
941     n = QDM2_SB_USED(q->sub_sampling) - 4;
942 
943     for (sb = 0; sb < n; sb++)
944         for (ch = 0; ch < q->nb_channels; ch++) {
945             if (get_bits_left(gb) < 16)
946                 break;
947             q->tone_level_idx_hi2[ch][sb] = qdm2_get_vlc(gb, &vlc_tab_tone_level_idx_hi2, 0, 2);
948             if (sb > 19)
949                 q->tone_level_idx_hi2[ch][sb] -= 16;
950             else
951                 for (j = 0; j < 8; j++)
952                     q->tone_level_idx_mid[ch][sb][j] = -16;
953         }
954 
955     n = QDM2_SB_USED(q->sub_sampling) - 5;
956 
957     for (sb = 0; sb < n; sb++)
958         for (ch = 0; ch < q->nb_channels; ch++)
959             for (j = 0; j < 8; j++) {
960                 if (get_bits_left(gb) < 16)
961                     break;
962                 q->tone_level_idx_mid[ch][sb][j] = qdm2_get_vlc(gb, &vlc_tab_tone_level_idx_mid, 0, 2) - 32;
963             }
964 }
965 
966 /**
967  * Process subpacket 9, init quantized_coeffs with data from it
968  *
969  * @param q       context
970  * @param node    pointer to node with packet
971  */
process_subpacket_9(QDM2Context * q,QDM2SubPNode * node)972 static int process_subpacket_9(QDM2Context *q, QDM2SubPNode *node)
973 {
974     GetBitContext gb;
975     int i, j, k, n, ch, run, level, diff;
976 
977     init_get_bits(&gb, node->packet->data, node->packet->size * 8);
978 
979     n = coeff_per_sb_for_avg[q->coeff_per_sb_select][QDM2_SB_USED(q->sub_sampling) - 1] + 1;
980 
981     for (i = 1; i < n; i++)
982         for (ch = 0; ch < q->nb_channels; ch++) {
983             level = qdm2_get_vlc(&gb, &vlc_tab_level, 0, 2);
984             q->quantized_coeffs[ch][i][0] = level;
985 
986             for (j = 0; j < (8 - 1); ) {
987                 run  = qdm2_get_vlc(&gb, &vlc_tab_run, 0, 1) + 1;
988                 diff = qdm2_get_se_vlc(&vlc_tab_diff, &gb, 2);
989 
990                 if (j + run >= 8)
991                     return -1;
992 
993                 for (k = 1; k <= run; k++)
994                     q->quantized_coeffs[ch][i][j + k] = (level + ((k * diff) / run));
995 
996                 level += diff;
997                 j     += run;
998             }
999         }
1000 
1001     for (ch = 0; ch < q->nb_channels; ch++)
1002         for (i = 0; i < 8; i++)
1003             q->quantized_coeffs[ch][0][i] = 0;
1004 
1005     return 0;
1006 }
1007 
1008 /**
1009  * Process subpacket 10 if not null, else
1010  *
1011  * @param q         context
1012  * @param node      pointer to node with packet
1013  */
process_subpacket_10(QDM2Context * q,QDM2SubPNode * node)1014 static void process_subpacket_10(QDM2Context *q, QDM2SubPNode *node)
1015 {
1016     GetBitContext gb;
1017 
1018     if (node) {
1019         init_get_bits(&gb, node->packet->data, node->packet->size * 8);
1020         init_tone_level_dequantization(q, &gb);
1021         fill_tone_level_array(q, 1);
1022     } else {
1023         fill_tone_level_array(q, 0);
1024     }
1025 }
1026 
1027 /**
1028  * Process subpacket 11
1029  *
1030  * @param q         context
1031  * @param node      pointer to node with packet
1032  */
process_subpacket_11(QDM2Context * q,QDM2SubPNode * node)1033 static void process_subpacket_11(QDM2Context *q, QDM2SubPNode *node)
1034 {
1035     GetBitContext gb;
1036     int length = 0;
1037 
1038     if (node) {
1039         length = node->packet->size * 8;
1040         init_get_bits(&gb, node->packet->data, length);
1041     }
1042 
1043     if (length >= 32) {
1044         int c = get_bits(&gb, 13);
1045 
1046         if (c > 3)
1047             fill_coding_method_array(q->tone_level_idx,
1048                                      q->tone_level_idx_temp, q->coding_method,
1049                                      q->nb_channels, 8 * c,
1050                                      q->superblocktype_2_3, q->cm_table_select);
1051     }
1052 
1053     synthfilt_build_sb_samples(q, &gb, length, 0, 8);
1054 }
1055 
1056 /**
1057  * Process subpacket 12
1058  *
1059  * @param q         context
1060  * @param node      pointer to node with packet
1061  */
process_subpacket_12(QDM2Context * q,QDM2SubPNode * node)1062 static void process_subpacket_12(QDM2Context *q, QDM2SubPNode *node)
1063 {
1064     GetBitContext gb;
1065     int length = 0;
1066 
1067     if (node) {
1068         length = node->packet->size * 8;
1069         init_get_bits(&gb, node->packet->data, length);
1070     }
1071 
1072     synthfilt_build_sb_samples(q, &gb, length, 8, QDM2_SB_USED(q->sub_sampling));
1073 }
1074 
1075 /**
1076  * Process new subpackets for synthesis filter
1077  *
1078  * @param q       context
1079  * @param list    list with synthesis filter packets (list D)
1080  */
process_synthesis_subpackets(QDM2Context * q,QDM2SubPNode * list)1081 static void process_synthesis_subpackets(QDM2Context *q, QDM2SubPNode *list)
1082 {
1083     QDM2SubPNode *nodes[4];
1084 
1085     nodes[0] = qdm2_search_subpacket_type_in_list(list, 9);
1086     if (nodes[0])
1087         process_subpacket_9(q, nodes[0]);
1088 
1089     nodes[1] = qdm2_search_subpacket_type_in_list(list, 10);
1090     if (nodes[1])
1091         process_subpacket_10(q, nodes[1]);
1092     else
1093         process_subpacket_10(q, NULL);
1094 
1095     nodes[2] = qdm2_search_subpacket_type_in_list(list, 11);
1096     if (nodes[0] && nodes[1] && nodes[2])
1097         process_subpacket_11(q, nodes[2]);
1098     else
1099         process_subpacket_11(q, NULL);
1100 
1101     nodes[3] = qdm2_search_subpacket_type_in_list(list, 12);
1102     if (nodes[0] && nodes[1] && nodes[3])
1103         process_subpacket_12(q, nodes[3]);
1104     else
1105         process_subpacket_12(q, NULL);
1106 }
1107 
1108 /**
1109  * Decode superblock, fill packet lists.
1110  *
1111  * @param q    context
1112  */
qdm2_decode_super_block(QDM2Context * q)1113 static void qdm2_decode_super_block(QDM2Context *q)
1114 {
1115     GetBitContext gb;
1116     QDM2SubPacket header, *packet;
1117     int i, packet_bytes, sub_packet_size, sub_packets_D;
1118     unsigned int next_index = 0;
1119 
1120     memset(q->tone_level_idx_hi1, 0, sizeof(q->tone_level_idx_hi1));
1121     memset(q->tone_level_idx_mid, 0, sizeof(q->tone_level_idx_mid));
1122     memset(q->tone_level_idx_hi2, 0, sizeof(q->tone_level_idx_hi2));
1123 
1124     q->sub_packets_B = 0;
1125     sub_packets_D    = 0;
1126 
1127     average_quantized_coeffs(q); // average elements in quantized_coeffs[max_ch][10][8]
1128 
1129     init_get_bits(&gb, q->compressed_data, q->compressed_size * 8);
1130     qdm2_decode_sub_packet_header(&gb, &header);
1131 
1132     if (header.type < 2 || header.type >= 8) {
1133         q->has_errors = 1;
1134         av_log(NULL, AV_LOG_ERROR, "bad superblock type\n");
1135         return;
1136     }
1137 
1138     q->superblocktype_2_3 = (header.type == 2 || header.type == 3);
1139     packet_bytes          = (q->compressed_size - get_bits_count(&gb) / 8);
1140 
1141     init_get_bits(&gb, header.data, header.size * 8);
1142 
1143     if (header.type == 2 || header.type == 4 || header.type == 5) {
1144         int csum = 257 * get_bits(&gb, 8);
1145         csum += 2 * get_bits(&gb, 8);
1146 
1147         csum = qdm2_packet_checksum(q->compressed_data, q->checksum_size, csum);
1148 
1149         if (csum != 0) {
1150             q->has_errors = 1;
1151             av_log(NULL, AV_LOG_ERROR, "bad packet checksum\n");
1152             return;
1153         }
1154     }
1155 
1156     q->sub_packet_list_B[0].packet = NULL;
1157     q->sub_packet_list_D[0].packet = NULL;
1158 
1159     for (i = 0; i < 6; i++)
1160         if (--q->fft_level_exp[i] < 0)
1161             q->fft_level_exp[i] = 0;
1162 
1163     for (i = 0; packet_bytes > 0; i++) {
1164         int j;
1165 
1166         if (i >= FF_ARRAY_ELEMS(q->sub_packet_list_A)) {
1167             SAMPLES_NEEDED_2("too many packet bytes");
1168             return;
1169         }
1170 
1171         q->sub_packet_list_A[i].next = NULL;
1172 
1173         if (i > 0) {
1174             q->sub_packet_list_A[i - 1].next = &q->sub_packet_list_A[i];
1175 
1176             /* seek to next block */
1177             init_get_bits(&gb, header.data, header.size * 8);
1178             skip_bits(&gb, next_index * 8);
1179 
1180             if (next_index >= header.size)
1181                 break;
1182         }
1183 
1184         /* decode subpacket */
1185         packet = &q->sub_packets[i];
1186         qdm2_decode_sub_packet_header(&gb, packet);
1187         next_index      = packet->size + get_bits_count(&gb) / 8;
1188         sub_packet_size = ((packet->size > 0xff) ? 1 : 0) + packet->size + 2;
1189 
1190         if (packet->type == 0)
1191             break;
1192 
1193         if (sub_packet_size > packet_bytes) {
1194             if (packet->type != 10 && packet->type != 11 && packet->type != 12)
1195                 break;
1196             packet->size += packet_bytes - sub_packet_size;
1197         }
1198 
1199         packet_bytes -= sub_packet_size;
1200 
1201         /* add subpacket to 'all subpackets' list */
1202         q->sub_packet_list_A[i].packet = packet;
1203 
1204         /* add subpacket to related list */
1205         if (packet->type == 8) {
1206             SAMPLES_NEEDED_2("packet type 8");
1207             return;
1208         } else if (packet->type >= 9 && packet->type <= 12) {
1209             /* packets for MPEG Audio like Synthesis Filter */
1210             QDM2_LIST_ADD(q->sub_packet_list_D, sub_packets_D, packet);
1211         } else if (packet->type == 13) {
1212             for (j = 0; j < 6; j++)
1213                 q->fft_level_exp[j] = get_bits(&gb, 6);
1214         } else if (packet->type == 14) {
1215             for (j = 0; j < 6; j++)
1216                 q->fft_level_exp[j] = qdm2_get_vlc(&gb, &fft_level_exp_vlc, 0, 2);
1217         } else if (packet->type == 15) {
1218             SAMPLES_NEEDED_2("packet type 15")
1219             return;
1220         } else if (packet->type >= 16 && packet->type < 48 &&
1221                    !fft_subpackets[packet->type - 16]) {
1222             /* packets for FFT */
1223             QDM2_LIST_ADD(q->sub_packet_list_B, q->sub_packets_B, packet);
1224         }
1225     } // Packet bytes loop
1226 
1227     if (q->sub_packet_list_D[0].packet) {
1228         process_synthesis_subpackets(q, q->sub_packet_list_D);
1229         q->do_synth_filter = 1;
1230     } else if (q->do_synth_filter) {
1231         process_subpacket_10(q, NULL);
1232         process_subpacket_11(q, NULL);
1233         process_subpacket_12(q, NULL);
1234     }
1235 }
1236 
qdm2_fft_init_coefficient(QDM2Context * q,int sub_packet,int offset,int duration,int channel,int exp,int phase)1237 static void qdm2_fft_init_coefficient(QDM2Context *q, int sub_packet,
1238                                       int offset, int duration, int channel,
1239                                       int exp, int phase)
1240 {
1241     if (q->fft_coefs_min_index[duration] < 0)
1242         q->fft_coefs_min_index[duration] = q->fft_coefs_index;
1243 
1244     q->fft_coefs[q->fft_coefs_index].sub_packet =
1245         ((sub_packet >= 16) ? (sub_packet - 16) : sub_packet);
1246     q->fft_coefs[q->fft_coefs_index].channel = channel;
1247     q->fft_coefs[q->fft_coefs_index].offset  = offset;
1248     q->fft_coefs[q->fft_coefs_index].exp     = exp;
1249     q->fft_coefs[q->fft_coefs_index].phase   = phase;
1250     q->fft_coefs_index++;
1251 }
1252 
qdm2_fft_decode_tones(QDM2Context * q,int duration,GetBitContext * gb,int b)1253 static void qdm2_fft_decode_tones(QDM2Context *q, int duration,
1254                                   GetBitContext *gb, int b)
1255 {
1256     int channel, stereo, phase, exp;
1257     int local_int_4, local_int_8, stereo_phase, local_int_10;
1258     int local_int_14, stereo_exp, local_int_20, local_int_28;
1259     int n, offset;
1260 
1261     local_int_4  = 0;
1262     local_int_28 = 0;
1263     local_int_20 = 2;
1264     local_int_8  = (4 - duration);
1265     local_int_10 = 1 << (q->group_order - duration - 1);
1266     offset       = 1;
1267 
1268     while (get_bits_left(gb)>0) {
1269         if (q->superblocktype_2_3) {
1270             while ((n = qdm2_get_vlc(gb, &vlc_tab_fft_tone_offset[local_int_8], 1, 2)) < 2) {
1271                 if (get_bits_left(gb)<0) {
1272                     if(local_int_4 < q->group_size)
1273                         av_log(NULL, AV_LOG_ERROR, "overread in qdm2_fft_decode_tones()\n");
1274                     return;
1275                 }
1276                 offset = 1;
1277                 if (n == 0) {
1278                     local_int_4  += local_int_10;
1279                     local_int_28 += (1 << local_int_8);
1280                 } else {
1281                     local_int_4  += 8 * local_int_10;
1282                     local_int_28 += (8 << local_int_8);
1283                 }
1284             }
1285             offset += (n - 2);
1286         } else {
1287             offset += qdm2_get_vlc(gb, &vlc_tab_fft_tone_offset[local_int_8], 1, 2);
1288             while (offset >= (local_int_10 - 1)) {
1289                 offset       += (1 - (local_int_10 - 1));
1290                 local_int_4  += local_int_10;
1291                 local_int_28 += (1 << local_int_8);
1292             }
1293         }
1294 
1295         if (local_int_4 >= q->group_size)
1296             return;
1297 
1298         local_int_14 = (offset >> local_int_8);
1299         if (local_int_14 >= FF_ARRAY_ELEMS(fft_level_index_table))
1300             return;
1301 
1302         if (q->nb_channels > 1) {
1303             channel = get_bits1(gb);
1304             stereo  = get_bits1(gb);
1305         } else {
1306             channel = 0;
1307             stereo  = 0;
1308         }
1309 
1310         exp  = qdm2_get_vlc(gb, (b ? &fft_level_exp_vlc : &fft_level_exp_alt_vlc), 0, 2);
1311         exp += q->fft_level_exp[fft_level_index_table[local_int_14]];
1312         exp  = (exp < 0) ? 0 : exp;
1313 
1314         phase        = get_bits(gb, 3);
1315         stereo_exp   = 0;
1316         stereo_phase = 0;
1317 
1318         if (stereo) {
1319             stereo_exp   = (exp - qdm2_get_vlc(gb, &fft_stereo_exp_vlc, 0, 1));
1320             stereo_phase = (phase - qdm2_get_vlc(gb, &fft_stereo_phase_vlc, 0, 1));
1321             if (stereo_phase < 0)
1322                 stereo_phase += 8;
1323         }
1324 
1325         if (q->frequency_range > (local_int_14 + 1)) {
1326             int sub_packet = (local_int_20 + local_int_28);
1327 
1328             qdm2_fft_init_coefficient(q, sub_packet, offset, duration,
1329                                       channel, exp, phase);
1330             if (stereo)
1331                 qdm2_fft_init_coefficient(q, sub_packet, offset, duration,
1332                                           1 - channel,
1333                                           stereo_exp, stereo_phase);
1334         }
1335         offset++;
1336     }
1337 }
1338 
qdm2_decode_fft_packets(QDM2Context * q)1339 static void qdm2_decode_fft_packets(QDM2Context *q)
1340 {
1341     int i, j, min, max, value, type, unknown_flag;
1342     GetBitContext gb;
1343 
1344     if (!q->sub_packet_list_B[0].packet)
1345         return;
1346 
1347     /* reset minimum indexes for FFT coefficients */
1348     q->fft_coefs_index = 0;
1349     for (i = 0; i < 5; i++)
1350         q->fft_coefs_min_index[i] = -1;
1351 
1352     /* process subpackets ordered by type, largest type first */
1353     for (i = 0, max = 256; i < q->sub_packets_B; i++) {
1354         QDM2SubPacket *packet = NULL;
1355 
1356         /* find subpacket with largest type less than max */
1357         for (j = 0, min = 0; j < q->sub_packets_B; j++) {
1358             value = q->sub_packet_list_B[j].packet->type;
1359             if (value > min && value < max) {
1360                 min    = value;
1361                 packet = q->sub_packet_list_B[j].packet;
1362             }
1363         }
1364 
1365         max = min;
1366 
1367         /* check for errors (?) */
1368         if (!packet)
1369             return;
1370 
1371         if (i == 0 &&
1372             (packet->type < 16 || packet->type >= 48 ||
1373              fft_subpackets[packet->type - 16]))
1374             return;
1375 
1376         /* decode FFT tones */
1377         init_get_bits(&gb, packet->data, packet->size * 8);
1378 
1379         if (packet->type >= 32 && packet->type < 48 && !fft_subpackets[packet->type - 16])
1380             unknown_flag = 1;
1381         else
1382             unknown_flag = 0;
1383 
1384         type = packet->type;
1385 
1386         if ((type >= 17 && type < 24) || (type >= 33 && type < 40)) {
1387             int duration = q->sub_sampling + 5 - (type & 15);
1388 
1389             if (duration >= 0 && duration < 4)
1390                 qdm2_fft_decode_tones(q, duration, &gb, unknown_flag);
1391         } else if (type == 31) {
1392             for (j = 0; j < 4; j++)
1393                 qdm2_fft_decode_tones(q, j, &gb, unknown_flag);
1394         } else if (type == 46) {
1395             for (j = 0; j < 6; j++)
1396                 q->fft_level_exp[j] = get_bits(&gb, 6);
1397             for (j = 0; j < 4; j++)
1398                 qdm2_fft_decode_tones(q, j, &gb, unknown_flag);
1399         }
1400     } // Loop on B packets
1401 
1402     /* calculate maximum indexes for FFT coefficients */
1403     for (i = 0, j = -1; i < 5; i++)
1404         if (q->fft_coefs_min_index[i] >= 0) {
1405             if (j >= 0)
1406                 q->fft_coefs_max_index[j] = q->fft_coefs_min_index[i];
1407             j = i;
1408         }
1409     if (j >= 0)
1410         q->fft_coefs_max_index[j] = q->fft_coefs_index;
1411 }
1412 
qdm2_fft_generate_tone(QDM2Context * q,FFTTone * tone)1413 static void qdm2_fft_generate_tone(QDM2Context *q, FFTTone *tone)
1414 {
1415     float level, f[6];
1416     int i;
1417     QDM2Complex c;
1418     const double iscale = 2.0 * M_PI / 512.0;
1419 
1420     tone->phase += tone->phase_shift;
1421 
1422     /* calculate current level (maximum amplitude) of tone */
1423     level = fft_tone_envelope_table[tone->duration][tone->time_index] * tone->level;
1424     c.im  = level * sin(tone->phase * iscale);
1425     c.re  = level * cos(tone->phase * iscale);
1426 
1427     /* generate FFT coefficients for tone */
1428     if (tone->duration >= 3 || tone->cutoff >= 3) {
1429         tone->complex[0].im += c.im;
1430         tone->complex[0].re += c.re;
1431         tone->complex[1].im -= c.im;
1432         tone->complex[1].re -= c.re;
1433     } else {
1434         f[1] = -tone->table[4];
1435         f[0] = tone->table[3] - tone->table[0];
1436         f[2] = 1.0 - tone->table[2] - tone->table[3];
1437         f[3] = tone->table[1] + tone->table[4] - 1.0;
1438         f[4] = tone->table[0] - tone->table[1];
1439         f[5] = tone->table[2];
1440         for (i = 0; i < 2; i++) {
1441             tone->complex[fft_cutoff_index_table[tone->cutoff][i]].re +=
1442                 c.re * f[i];
1443             tone->complex[fft_cutoff_index_table[tone->cutoff][i]].im +=
1444                 c.im * ((tone->cutoff <= i) ? -f[i] : f[i]);
1445         }
1446         for (i = 0; i < 4; i++) {
1447             tone->complex[i].re += c.re * f[i + 2];
1448             tone->complex[i].im += c.im * f[i + 2];
1449         }
1450     }
1451 
1452     /* copy the tone if it has not yet died out */
1453     if (++tone->time_index < ((1 << (5 - tone->duration)) - 1)) {
1454         memcpy(&q->fft_tones[q->fft_tone_end], tone, sizeof(FFTTone));
1455         q->fft_tone_end = (q->fft_tone_end + 1) % 1000;
1456     }
1457 }
1458 
qdm2_fft_tone_synthesizer(QDM2Context * q,int sub_packet)1459 static void qdm2_fft_tone_synthesizer(QDM2Context *q, int sub_packet)
1460 {
1461     int i, j, ch;
1462     const double iscale = 0.25 * M_PI;
1463 
1464     for (ch = 0; ch < q->channels; ch++) {
1465         memset(q->fft.complex[ch], 0, q->fft_size * sizeof(QDM2Complex));
1466     }
1467 
1468 
1469     /* apply FFT tones with duration 4 (1 FFT period) */
1470     if (q->fft_coefs_min_index[4] >= 0)
1471         for (i = q->fft_coefs_min_index[4]; i < q->fft_coefs_max_index[4]; i++) {
1472             float level;
1473             QDM2Complex c;
1474 
1475             if (q->fft_coefs[i].sub_packet != sub_packet)
1476                 break;
1477 
1478             ch = (q->channels == 1) ? 0 : q->fft_coefs[i].channel;
1479             level = (q->fft_coefs[i].exp < 0) ? 0.0 : fft_tone_level_table[q->superblocktype_2_3 ? 0 : 1][q->fft_coefs[i].exp & 63];
1480 
1481             c.re = level * cos(q->fft_coefs[i].phase * iscale);
1482             c.im = level * sin(q->fft_coefs[i].phase * iscale);
1483             q->fft.complex[ch][q->fft_coefs[i].offset + 0].re += c.re;
1484             q->fft.complex[ch][q->fft_coefs[i].offset + 0].im += c.im;
1485             q->fft.complex[ch][q->fft_coefs[i].offset + 1].re -= c.re;
1486             q->fft.complex[ch][q->fft_coefs[i].offset + 1].im -= c.im;
1487         }
1488 
1489     /* generate existing FFT tones */
1490     for (i = q->fft_tone_end; i != q->fft_tone_start; ) {
1491         qdm2_fft_generate_tone(q, &q->fft_tones[q->fft_tone_start]);
1492         q->fft_tone_start = (q->fft_tone_start + 1) % 1000;
1493     }
1494 
1495     /* create and generate new FFT tones with duration 0 (long) to 3 (short) */
1496     for (i = 0; i < 4; i++)
1497         if (q->fft_coefs_min_index[i] >= 0) {
1498             for (j = q->fft_coefs_min_index[i]; j < q->fft_coefs_max_index[i]; j++) {
1499                 int offset, four_i;
1500                 FFTTone tone;
1501 
1502                 if (q->fft_coefs[j].sub_packet != sub_packet)
1503                     break;
1504 
1505                 four_i = (4 - i);
1506                 offset = q->fft_coefs[j].offset >> four_i;
1507                 ch = (q->channels == 1) ? 0 : q->fft_coefs[j].channel;
1508 
1509                 if (offset < q->frequency_range) {
1510                     if (offset < 2)
1511                         tone.cutoff = offset;
1512                     else
1513                         tone.cutoff = (offset >= 60) ? 3 : 2;
1514 
1515                     tone.level = (q->fft_coefs[j].exp < 0) ? 0.0 : fft_tone_level_table[q->superblocktype_2_3 ? 0 : 1][q->fft_coefs[j].exp & 63];
1516                     tone.complex = &q->fft.complex[ch][offset];
1517                     tone.table = fft_tone_sample_table[i][q->fft_coefs[j].offset - (offset << four_i)];
1518                     tone.phase = 64 * q->fft_coefs[j].phase - (offset << 8) - 128;
1519                     tone.phase_shift = (2 * q->fft_coefs[j].offset + 1) << (7 - four_i);
1520                     tone.duration = i;
1521                     tone.time_index = 0;
1522 
1523                     qdm2_fft_generate_tone(q, &tone);
1524                 }
1525             }
1526             q->fft_coefs_min_index[i] = j;
1527         }
1528 }
1529 
qdm2_calculate_fft(QDM2Context * q,int channel,int sub_packet)1530 static void qdm2_calculate_fft(QDM2Context *q, int channel, int sub_packet)
1531 {
1532     const float gain = (q->channels == 1 && q->nb_channels == 2) ? 0.5f : 1.0f;
1533     float *out       = q->output_buffer + channel;
1534     int i;
1535     q->fft.complex[channel][0].re *= 2.0f;
1536     q->fft.complex[channel][0].im  = 0.0f;
1537     q->rdft_ctx.rdft_calc(&q->rdft_ctx, (FFTSample *)q->fft.complex[channel]);
1538     /* add samples to output buffer */
1539     for (i = 0; i < FFALIGN(q->fft_size, 8); i++) {
1540         out[0]           += q->fft.complex[channel][i].re * gain;
1541         out[q->channels] += q->fft.complex[channel][i].im * gain;
1542         out              += 2 * q->channels;
1543     }
1544 }
1545 
1546 /**
1547  * @param q        context
1548  * @param index    subpacket number
1549  */
qdm2_synthesis_filter(QDM2Context * q,int index)1550 static void qdm2_synthesis_filter(QDM2Context *q, int index)
1551 {
1552     int i, k, ch, sb_used, sub_sampling, dither_state = 0;
1553 
1554     /* copy sb_samples */
1555     sb_used = QDM2_SB_USED(q->sub_sampling);
1556 
1557     for (ch = 0; ch < q->channels; ch++)
1558         for (i = 0; i < 8; i++)
1559             for (k = sb_used; k < SBLIMIT; k++)
1560                 q->sb_samples[ch][(8 * index) + i][k] = 0;
1561 
1562     for (ch = 0; ch < q->nb_channels; ch++) {
1563         float *samples_ptr = q->samples + ch;
1564 
1565         for (i = 0; i < 8; i++) {
1566             ff_mpa_synth_filter_float(&q->mpadsp,
1567                                       q->synth_buf[ch], &(q->synth_buf_offset[ch]),
1568                                       ff_mpa_synth_window_float, &dither_state,
1569                                       samples_ptr, q->nb_channels,
1570                                       q->sb_samples[ch][(8 * index) + i]);
1571             samples_ptr += 32 * q->nb_channels;
1572         }
1573     }
1574 
1575     /* add samples to output buffer */
1576     sub_sampling = (4 >> q->sub_sampling);
1577 
1578     for (ch = 0; ch < q->channels; ch++)
1579         for (i = 0; i < q->frame_size; i++)
1580             q->output_buffer[q->channels * i + ch] += (1 << 23) * q->samples[q->nb_channels * sub_sampling * i + ch];
1581 }
1582 
1583 /**
1584  * Init static data (does not depend on specific file)
1585  *
1586  * @param q    context
1587  */
qdm2_init_static_data(void)1588 static av_cold void qdm2_init_static_data(void) {
1589     static int done;
1590 
1591     if(done)
1592         return;
1593 
1594     qdm2_init_vlc();
1595     ff_mpa_synth_init_float(ff_mpa_synth_window_float);
1596     softclip_table_init();
1597     rnd_table_init();
1598     init_noise_samples();
1599 
1600     done = 1;
1601 }
1602 
1603 /**
1604  * Init parameters from codec extradata
1605  */
qdm2_decode_init(AVCodecContext * avctx)1606 static av_cold int qdm2_decode_init(AVCodecContext *avctx)
1607 {
1608     QDM2Context *s = avctx->priv_data;
1609     int tmp_val, tmp, size;
1610     GetByteContext gb;
1611 
1612     qdm2_init_static_data();
1613 
1614     /* extradata parsing
1615 
1616     Structure:
1617     wave {
1618         frma (QDM2)
1619         QDCA
1620         QDCP
1621     }
1622 
1623     32  size (including this field)
1624     32  tag (=frma)
1625     32  type (=QDM2 or QDMC)
1626 
1627     32  size (including this field, in bytes)
1628     32  tag (=QDCA) // maybe mandatory parameters
1629     32  unknown (=1)
1630     32  channels (=2)
1631     32  samplerate (=44100)
1632     32  bitrate (=96000)
1633     32  block size (=4096)
1634     32  frame size (=256) (for one channel)
1635     32  packet size (=1300)
1636 
1637     32  size (including this field, in bytes)
1638     32  tag (=QDCP) // maybe some tuneable parameters
1639     32  float1 (=1.0)
1640     32  zero ?
1641     32  float2 (=1.0)
1642     32  float3 (=1.0)
1643     32  unknown (27)
1644     32  unknown (8)
1645     32  zero ?
1646     */
1647 
1648     if (!avctx->extradata || (avctx->extradata_size < 48)) {
1649         av_log(avctx, AV_LOG_ERROR, "extradata missing or truncated\n");
1650         return AVERROR_INVALIDDATA;
1651     }
1652 
1653     bytestream2_init(&gb, avctx->extradata, avctx->extradata_size);
1654 
1655     while (bytestream2_get_bytes_left(&gb) > 8) {
1656         if (bytestream2_peek_be64(&gb) == (((uint64_t)MKBETAG('f','r','m','a') << 32) |
1657                                             (uint64_t)MKBETAG('Q','D','M','2')))
1658             break;
1659         bytestream2_skip(&gb, 1);
1660     }
1661 
1662     if (bytestream2_get_bytes_left(&gb) < 12) {
1663         av_log(avctx, AV_LOG_ERROR, "not enough extradata (%i)\n",
1664                bytestream2_get_bytes_left(&gb));
1665         return AVERROR_INVALIDDATA;
1666     }
1667 
1668     bytestream2_skip(&gb, 8);
1669     size = bytestream2_get_be32(&gb);
1670 
1671     if (size > bytestream2_get_bytes_left(&gb)) {
1672         av_log(avctx, AV_LOG_ERROR, "extradata size too small, %i < %i\n",
1673                bytestream2_get_bytes_left(&gb), size);
1674         return AVERROR_INVALIDDATA;
1675     }
1676 
1677     av_log(avctx, AV_LOG_DEBUG, "size: %d\n", size);
1678     if (bytestream2_get_be32(&gb) != MKBETAG('Q','D','C','A')) {
1679         av_log(avctx, AV_LOG_ERROR, "invalid extradata, expecting QDCA\n");
1680         return AVERROR_INVALIDDATA;
1681     }
1682 
1683     bytestream2_skip(&gb, 4);
1684 
1685     avctx->channels = s->nb_channels = s->channels = bytestream2_get_be32(&gb);
1686     if (s->channels <= 0 || s->channels > MPA_MAX_CHANNELS) {
1687         av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n");
1688         return AVERROR_INVALIDDATA;
1689     }
1690     avctx->channel_layout = avctx->channels == 2 ? AV_CH_LAYOUT_STEREO :
1691                                                    AV_CH_LAYOUT_MONO;
1692 
1693     avctx->sample_rate = bytestream2_get_be32(&gb);
1694     avctx->bit_rate = bytestream2_get_be32(&gb);
1695     s->group_size = bytestream2_get_be32(&gb);
1696     s->fft_size = bytestream2_get_be32(&gb);
1697     s->checksum_size = bytestream2_get_be32(&gb);
1698     if (s->checksum_size >= 1U << 28) {
1699         av_log(avctx, AV_LOG_ERROR, "data block size too large (%u)\n", s->checksum_size);
1700         return AVERROR_INVALIDDATA;
1701     }
1702 
1703     s->fft_order = av_log2(s->fft_size) + 1;
1704 
1705     // something like max decodable tones
1706     s->group_order = av_log2(s->group_size) + 1;
1707     s->frame_size = s->group_size / 16; // 16 iterations per super block
1708 
1709     if (s->frame_size > QDM2_MAX_FRAME_SIZE)
1710         return AVERROR_INVALIDDATA;
1711 
1712     s->sub_sampling = s->fft_order - 7;
1713     s->frequency_range = 255 / (1 << (2 - s->sub_sampling));
1714 
1715     switch ((s->sub_sampling * 2 + s->channels - 1)) {
1716         case 0: tmp = 40; break;
1717         case 1: tmp = 48; break;
1718         case 2: tmp = 56; break;
1719         case 3: tmp = 72; break;
1720         case 4: tmp = 80; break;
1721         case 5: tmp = 100;break;
1722         default: tmp=s->sub_sampling; break;
1723     }
1724     tmp_val = 0;
1725     if ((tmp * 1000) < avctx->bit_rate)  tmp_val = 1;
1726     if ((tmp * 1440) < avctx->bit_rate)  tmp_val = 2;
1727     if ((tmp * 1760) < avctx->bit_rate)  tmp_val = 3;
1728     if ((tmp * 2240) < avctx->bit_rate)  tmp_val = 4;
1729     s->cm_table_select = tmp_val;
1730 
1731     if (avctx->bit_rate <= 8000)
1732         s->coeff_per_sb_select = 0;
1733     else if (avctx->bit_rate < 16000)
1734         s->coeff_per_sb_select = 1;
1735     else
1736         s->coeff_per_sb_select = 2;
1737 
1738     // Fail on unknown fft order
1739     if ((s->fft_order < 7) || (s->fft_order > 9)) {
1740         avpriv_request_sample(avctx, "Unknown FFT order %d", s->fft_order);
1741         return AVERROR_PATCHWELCOME;
1742     }
1743     if (s->fft_size != (1 << (s->fft_order - 1))) {
1744         av_log(avctx, AV_LOG_ERROR, "FFT size %d not power of 2.\n", s->fft_size);
1745         return AVERROR_INVALIDDATA;
1746     }
1747 
1748     ff_rdft_init(&s->rdft_ctx, s->fft_order, IDFT_C2R);
1749     ff_mpadsp_init(&s->mpadsp);
1750 
1751     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
1752 
1753     return 0;
1754 }
1755 
qdm2_decode_close(AVCodecContext * avctx)1756 static av_cold int qdm2_decode_close(AVCodecContext *avctx)
1757 {
1758     QDM2Context *s = avctx->priv_data;
1759 
1760     ff_rdft_end(&s->rdft_ctx);
1761 
1762     return 0;
1763 }
1764 
qdm2_decode(QDM2Context * q,const uint8_t * in,int16_t * out)1765 static int qdm2_decode(QDM2Context *q, const uint8_t *in, int16_t *out)
1766 {
1767     int ch, i;
1768     const int frame_size = (q->frame_size * q->channels);
1769 
1770     if((unsigned)frame_size > FF_ARRAY_ELEMS(q->output_buffer)/2)
1771         return -1;
1772 
1773     /* select input buffer */
1774     q->compressed_data = in;
1775     q->compressed_size = q->checksum_size;
1776 
1777     /* copy old block, clear new block of output samples */
1778     memmove(q->output_buffer, &q->output_buffer[frame_size], frame_size * sizeof(float));
1779     memset(&q->output_buffer[frame_size], 0, frame_size * sizeof(float));
1780 
1781     /* decode block of QDM2 compressed data */
1782     if (q->sub_packet == 0) {
1783         q->has_errors = 0; // zero it for a new super block
1784         av_log(NULL,AV_LOG_DEBUG,"Superblock follows\n");
1785         qdm2_decode_super_block(q);
1786     }
1787 
1788     /* parse subpackets */
1789     if (!q->has_errors) {
1790         if (q->sub_packet == 2)
1791             qdm2_decode_fft_packets(q);
1792 
1793         qdm2_fft_tone_synthesizer(q, q->sub_packet);
1794     }
1795 
1796     /* sound synthesis stage 1 (FFT) */
1797     for (ch = 0; ch < q->channels; ch++) {
1798         qdm2_calculate_fft(q, ch, q->sub_packet);
1799 
1800         if (!q->has_errors && q->sub_packet_list_C[0].packet) {
1801             SAMPLES_NEEDED_2("has errors, and C list is not empty")
1802             return -1;
1803         }
1804     }
1805 
1806     /* sound synthesis stage 2 (MPEG audio like synthesis filter) */
1807     if (!q->has_errors && q->do_synth_filter)
1808         qdm2_synthesis_filter(q, q->sub_packet);
1809 
1810     q->sub_packet = (q->sub_packet + 1) % 16;
1811 
1812     /* clip and convert output float[] to 16-bit signed samples */
1813     for (i = 0; i < frame_size; i++) {
1814         int value = (int)q->output_buffer[i];
1815 
1816         if (value > SOFTCLIP_THRESHOLD)
1817             value = (value >  HARDCLIP_THRESHOLD) ?  32767 :  softclip_table[ value - SOFTCLIP_THRESHOLD];
1818         else if (value < -SOFTCLIP_THRESHOLD)
1819             value = (value < -HARDCLIP_THRESHOLD) ? -32767 : -softclip_table[-value - SOFTCLIP_THRESHOLD];
1820 
1821         out[i] = value;
1822     }
1823 
1824     return 0;
1825 }
1826 
qdm2_decode_frame(AVCodecContext * avctx,void * data,int * got_frame_ptr,AVPacket * avpkt)1827 static int qdm2_decode_frame(AVCodecContext *avctx, void *data,
1828                              int *got_frame_ptr, AVPacket *avpkt)
1829 {
1830     AVFrame *frame     = data;
1831     const uint8_t *buf = avpkt->data;
1832     int buf_size = avpkt->size;
1833     QDM2Context *s = avctx->priv_data;
1834     int16_t *out;
1835     int i, ret;
1836 
1837     if(!buf)
1838         return 0;
1839     if(buf_size < s->checksum_size)
1840         return -1;
1841 
1842     /* get output buffer */
1843     frame->nb_samples = 16 * s->frame_size;
1844     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1845         return ret;
1846     out = (int16_t *)frame->data[0];
1847 
1848     for (i = 0; i < 16; i++) {
1849         if ((ret = qdm2_decode(s, buf, out)) < 0)
1850             return ret;
1851         out += s->channels * s->frame_size;
1852     }
1853 
1854     *got_frame_ptr = 1;
1855 
1856     return s->checksum_size;
1857 }
1858 
1859 AVCodec ff_qdm2_decoder = {
1860     .name             = "qdm2",
1861     .long_name        = NULL_IF_CONFIG_SMALL("QDesign Music Codec 2"),
1862     .type             = AVMEDIA_TYPE_AUDIO,
1863     .id               = AV_CODEC_ID_QDM2,
1864     .priv_data_size   = sizeof(QDM2Context),
1865     .init             = qdm2_decode_init,
1866     .close            = qdm2_decode_close,
1867     .decode           = qdm2_decode_frame,
1868     .capabilities     = AV_CODEC_CAP_DR1,
1869 };
1870