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alsdec.c
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1 /*
2  * MPEG-4 ALS decoder
3  * Copyright (c) 2009 Thilo Borgmann <thilo.borgmann _at_ googlemail.com>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * MPEG-4 ALS decoder
25  * @author Thilo Borgmann <thilo.borgmann _at_ googlemail.com>
26  */
27 
28 
29 //#define DEBUG
30 
31 
32 #include "avcodec.h"
33 #include "get_bits.h"
34 #include "unary.h"
35 #include "mpeg4audio.h"
36 #include "bytestream.h"
37 #include "bgmc.h"
38 #include "dsputil.h"
39 #include "internal.h"
40 #include "libavutil/samplefmt.h"
41 #include "libavutil/crc.h"
42 
43 #include <stdint.h>
44 
45 /** Rice parameters and corresponding index offsets for decoding the
46  * indices of scaled PARCOR values. The table chosen is set globally
47  * by the encoder and stored in ALSSpecificConfig.
48  */
49 static const int8_t parcor_rice_table[3][20][2] = {
50  { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},
51  { 12, 3}, { -7, 3}, { 9, 3}, { -5, 3}, { 6, 3},
52  { -4, 3}, { 3, 3}, { -3, 2}, { 3, 2}, { -2, 2},
53  { 3, 2}, { -1, 2}, { 2, 2}, { -1, 2}, { 2, 2} },
54  { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},
55  { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},
56  {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},
57  { 7, 3}, { -4, 4}, { 3, 3}, { -1, 3}, { 1, 3} },
58  { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},
59  { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},
60  {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},
61  { 3, 3}, { 0, 3}, { -1, 3}, { 2, 3}, { -1, 2} }
62 };
63 
64 
65 /** Scaled PARCOR values used for the first two PARCOR coefficients.
66  * To be indexed by the Rice coded indices.
67  * Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20)
68  * Actual values are divided by 32 in order to be stored in 16 bits.
69  */
70 static const int16_t parcor_scaled_values[] = {
71  -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,
72  -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,
73  -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,
74  -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,
75  -1013728 / 32, -1009376 / 32, -1004768 / 32, -999904 / 32,
76  -994784 / 32, -989408 / 32, -983776 / 32, -977888 / 32,
77  -971744 / 32, -965344 / 32, -958688 / 32, -951776 / 32,
78  -944608 / 32, -937184 / 32, -929504 / 32, -921568 / 32,
79  -913376 / 32, -904928 / 32, -896224 / 32, -887264 / 32,
80  -878048 / 32, -868576 / 32, -858848 / 32, -848864 / 32,
81  -838624 / 32, -828128 / 32, -817376 / 32, -806368 / 32,
82  -795104 / 32, -783584 / 32, -771808 / 32, -759776 / 32,
83  -747488 / 32, -734944 / 32, -722144 / 32, -709088 / 32,
84  -695776 / 32, -682208 / 32, -668384 / 32, -654304 / 32,
85  -639968 / 32, -625376 / 32, -610528 / 32, -595424 / 32,
86  -580064 / 32, -564448 / 32, -548576 / 32, -532448 / 32,
87  -516064 / 32, -499424 / 32, -482528 / 32, -465376 / 32,
88  -447968 / 32, -430304 / 32, -412384 / 32, -394208 / 32,
89  -375776 / 32, -357088 / 32, -338144 / 32, -318944 / 32,
90  -299488 / 32, -279776 / 32, -259808 / 32, -239584 / 32,
91  -219104 / 32, -198368 / 32, -177376 / 32, -156128 / 32,
92  -134624 / 32, -112864 / 32, -90848 / 32, -68576 / 32,
93  -46048 / 32, -23264 / 32, -224 / 32, 23072 / 32,
94  46624 / 32, 70432 / 32, 94496 / 32, 118816 / 32,
95  143392 / 32, 168224 / 32, 193312 / 32, 218656 / 32,
96  244256 / 32, 270112 / 32, 296224 / 32, 322592 / 32,
97  349216 / 32, 376096 / 32, 403232 / 32, 430624 / 32,
98  458272 / 32, 486176 / 32, 514336 / 32, 542752 / 32,
99  571424 / 32, 600352 / 32, 629536 / 32, 658976 / 32,
100  688672 / 32, 718624 / 32, 748832 / 32, 779296 / 32,
101  810016 / 32, 840992 / 32, 872224 / 32, 903712 / 32,
102  935456 / 32, 967456 / 32, 999712 / 32, 1032224 / 32
103 };
104 
105 
106 /** Gain values of p(0) for long-term prediction.
107  * To be indexed by the Rice coded indices.
108  */
109 static const uint8_t ltp_gain_values [4][4] = {
110  { 0, 8, 16, 24},
111  {32, 40, 48, 56},
112  {64, 70, 76, 82},
113  {88, 92, 96, 100}
114 };
115 
116 
117 /** Inter-channel weighting factors for multi-channel correlation.
118  * To be indexed by the Rice coded indices.
119  */
120 static const int16_t mcc_weightings[] = {
121  204, 192, 179, 166, 153, 140, 128, 115,
122  102, 89, 76, 64, 51, 38, 25, 12,
123  0, -12, -25, -38, -51, -64, -76, -89,
124  -102, -115, -128, -140, -153, -166, -179, -192
125 };
126 
127 
128 /** Tail codes used in arithmetic coding using block Gilbert-Moore codes.
129  */
130 static const uint8_t tail_code[16][6] = {
131  { 74, 44, 25, 13, 7, 3},
132  { 68, 42, 24, 13, 7, 3},
133  { 58, 39, 23, 13, 7, 3},
134  {126, 70, 37, 19, 10, 5},
135  {132, 70, 37, 20, 10, 5},
136  {124, 70, 38, 20, 10, 5},
137  {120, 69, 37, 20, 11, 5},
138  {116, 67, 37, 20, 11, 5},
139  {108, 66, 36, 20, 10, 5},
140  {102, 62, 36, 20, 10, 5},
141  { 88, 58, 34, 19, 10, 5},
142  {162, 89, 49, 25, 13, 7},
143  {156, 87, 49, 26, 14, 7},
144  {150, 86, 47, 26, 14, 7},
145  {142, 84, 47, 26, 14, 7},
146  {131, 79, 46, 26, 14, 7}
147 };
148 
149 
150 enum RA_Flag {
151  RA_FLAG_NONE,
152  RA_FLAG_FRAMES,
153  RA_FLAG_HEADER
154 };
155 
156 
157 typedef struct {
158  uint32_t samples; ///< number of samples, 0xFFFFFFFF if unknown
159  int resolution; ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit
160  int floating; ///< 1 = IEEE 32-bit floating-point, 0 = integer
161  int msb_first; ///< 1 = original CRC calculated on big-endian system, 0 = little-endian
162  int frame_length; ///< frame length for each frame (last frame may differ)
163  int ra_distance; ///< distance between RA frames (in frames, 0...255)
164  enum RA_Flag ra_flag; ///< indicates where the size of ra units is stored
165  int adapt_order; ///< adaptive order: 1 = on, 0 = off
166  int coef_table; ///< table index of Rice code parameters
167  int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off
168  int max_order; ///< maximum prediction order (0..1023)
169  int block_switching; ///< number of block switching levels
170  int bgmc; ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)
171  int sb_part; ///< sub-block partition
172  int joint_stereo; ///< joint stereo: 1 = on, 0 = off
173  int mc_coding; ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off
174  int chan_config; ///< indicates that a chan_config_info field is present
175  int chan_sort; ///< channel rearrangement: 1 = on, 0 = off
176  int rlslms; ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off
177  int chan_config_info; ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.
178  int *chan_pos; ///< original channel positions
179  int crc_enabled; ///< enable Cyclic Redundancy Checksum
180 } ALSSpecificConfig;
181 
182 
183 typedef struct {
184  int stop_flag;
185  int master_channel;
186  int time_diff_flag;
187  int time_diff_sign;
188  int time_diff_index;
189  int weighting[6];
190 } ALSChannelData;
191 
192 
193 typedef struct {
194  AVCodecContext *avctx;
195  AVFrame frame;
196  ALSSpecificConfig sconf;
197  GetBitContext gb;
198  DSPContext dsp;
199  const AVCRC *crc_table;
200  uint32_t crc_org; ///< CRC value of the original input data
201  uint32_t crc; ///< CRC value calculated from decoded data
202  unsigned int cur_frame_length; ///< length of the current frame to decode
203  unsigned int frame_id; ///< the frame ID / number of the current frame
204  unsigned int js_switch; ///< if true, joint-stereo decoding is enforced
205  unsigned int cs_switch; ///< if true, channel rearrangement is done
206  unsigned int num_blocks; ///< number of blocks used in the current frame
207  unsigned int s_max; ///< maximum Rice parameter allowed in entropy coding
208  uint8_t *bgmc_lut; ///< pointer at lookup tables used for BGMC
209  int *bgmc_lut_status; ///< pointer at lookup table status flags used for BGMC
210  int ltp_lag_length; ///< number of bits used for ltp lag value
211  int *const_block; ///< contains const_block flags for all channels
212  unsigned int *shift_lsbs; ///< contains shift_lsbs flags for all channels
213  unsigned int *opt_order; ///< contains opt_order flags for all channels
214  int *store_prev_samples; ///< contains store_prev_samples flags for all channels
215  int *use_ltp; ///< contains use_ltp flags for all channels
216  int *ltp_lag; ///< contains ltp lag values for all channels
217  int **ltp_gain; ///< gain values for ltp 5-tap filter for a channel
218  int *ltp_gain_buffer; ///< contains all gain values for ltp 5-tap filter
219  int32_t **quant_cof; ///< quantized parcor coefficients for a channel
220  int32_t *quant_cof_buffer; ///< contains all quantized parcor coefficients
221  int32_t **lpc_cof; ///< coefficients of the direct form prediction filter for a channel
222  int32_t *lpc_cof_buffer; ///< contains all coefficients of the direct form prediction filter
223  int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer
224  ALSChannelData **chan_data; ///< channel data for multi-channel correlation
225  ALSChannelData *chan_data_buffer; ///< contains channel data for all channels
226  int *reverted_channels; ///< stores a flag for each reverted channel
227  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
228  int32_t **raw_samples; ///< decoded raw samples for each channel
229  int32_t *raw_buffer; ///< contains all decoded raw samples including carryover samples
230  uint8_t *crc_buffer; ///< buffer of byte order corrected samples used for CRC check
231 } ALSDecContext;
232 
233 
234 typedef struct {
235  unsigned int block_length; ///< number of samples within the block
236  unsigned int ra_block; ///< if true, this is a random access block
237  int *const_block; ///< if true, this is a constant value block
238  int js_blocks; ///< true if this block contains a difference signal
239  unsigned int *shift_lsbs; ///< shift of values for this block
240  unsigned int *opt_order; ///< prediction order of this block
241  int *store_prev_samples;///< if true, carryover samples have to be stored
242  int *use_ltp; ///< if true, long-term prediction is used
243  int *ltp_lag; ///< lag value for long-term prediction
244  int *ltp_gain; ///< gain values for ltp 5-tap filter
245  int32_t *quant_cof; ///< quantized parcor coefficients
246  int32_t *lpc_cof; ///< coefficients of the direct form prediction
247  int32_t *raw_samples; ///< decoded raw samples / residuals for this block
248  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
249  int32_t *raw_other; ///< decoded raw samples of the other channel of a channel pair
250 } ALSBlockData;
251 
252 
253 static av_cold void dprint_specific_config(ALSDecContext *ctx)
254 {
255 #ifdef DEBUG
256  AVCodecContext *avctx = ctx->avctx;
257  ALSSpecificConfig *sconf = &ctx->sconf;
258 
259  av_dlog(avctx, "resolution = %i\n", sconf->resolution);
260  av_dlog(avctx, "floating = %i\n", sconf->floating);
261  av_dlog(avctx, "frame_length = %i\n", sconf->frame_length);
262  av_dlog(avctx, "ra_distance = %i\n", sconf->ra_distance);
263  av_dlog(avctx, "ra_flag = %i\n", sconf->ra_flag);
264  av_dlog(avctx, "adapt_order = %i\n", sconf->adapt_order);
265  av_dlog(avctx, "coef_table = %i\n", sconf->coef_table);
266  av_dlog(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);
267  av_dlog(avctx, "max_order = %i\n", sconf->max_order);
268  av_dlog(avctx, "block_switching = %i\n", sconf->block_switching);
269  av_dlog(avctx, "bgmc = %i\n", sconf->bgmc);
270  av_dlog(avctx, "sb_part = %i\n", sconf->sb_part);
271  av_dlog(avctx, "joint_stereo = %i\n", sconf->joint_stereo);
272  av_dlog(avctx, "mc_coding = %i\n", sconf->mc_coding);
273  av_dlog(avctx, "chan_config = %i\n", sconf->chan_config);
274  av_dlog(avctx, "chan_sort = %i\n", sconf->chan_sort);
275  av_dlog(avctx, "RLSLMS = %i\n", sconf->rlslms);
276  av_dlog(avctx, "chan_config_info = %i\n", sconf->chan_config_info);
277 #endif
278 }
279 
280 
281 /** Read an ALSSpecificConfig from a buffer into the output struct.
282  */
283 static av_cold int read_specific_config(ALSDecContext *ctx)
284 {
285  GetBitContext gb;
286  uint64_t ht_size;
287  int i, config_offset;
288  MPEG4AudioConfig m4ac;
289  ALSSpecificConfig *sconf = &ctx->sconf;
290  AVCodecContext *avctx = ctx->avctx;
291  uint32_t als_id, header_size, trailer_size;
292 
293  init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);
294 
295  config_offset = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata,
296  avctx->extradata_size * 8, 1);
297 
298  if (config_offset < 0)
299  return -1;
300 
301  skip_bits_long(&gb, config_offset);
302 
303  if (get_bits_left(&gb) < (30 << 3))
304  return -1;
305 
306  // read the fixed items
307  als_id = get_bits_long(&gb, 32);
308  avctx->sample_rate = m4ac.sample_rate;
309  skip_bits_long(&gb, 32); // sample rate already known
310  sconf->samples = get_bits_long(&gb, 32);
311  avctx->channels = m4ac.channels;
312  skip_bits(&gb, 16); // number of channels already known
313  skip_bits(&gb, 3); // skip file_type
314  sconf->resolution = get_bits(&gb, 3);
315  sconf->floating = get_bits1(&gb);
316  sconf->msb_first = get_bits1(&gb);
317  sconf->frame_length = get_bits(&gb, 16) + 1;
318  sconf->ra_distance = get_bits(&gb, 8);
319  sconf->ra_flag = get_bits(&gb, 2);
320  sconf->adapt_order = get_bits1(&gb);
321  sconf->coef_table = get_bits(&gb, 2);
322  sconf->long_term_prediction = get_bits1(&gb);
323  sconf->max_order = get_bits(&gb, 10);
324  sconf->block_switching = get_bits(&gb, 2);
325  sconf->bgmc = get_bits1(&gb);
326  sconf->sb_part = get_bits1(&gb);
327  sconf->joint_stereo = get_bits1(&gb);
328  sconf->mc_coding = get_bits1(&gb);
329  sconf->chan_config = get_bits1(&gb);
330  sconf->chan_sort = get_bits1(&gb);
331  sconf->crc_enabled = get_bits1(&gb);
332  sconf->rlslms = get_bits1(&gb);
333  skip_bits(&gb, 5); // skip 5 reserved bits
334  skip_bits1(&gb); // skip aux_data_enabled
335 
336 
337  // check for ALSSpecificConfig struct
338  if (als_id != MKBETAG('A','L','S','\0'))
339  return -1;
340 
341  ctx->cur_frame_length = sconf->frame_length;
342 
343  // read channel config
344  if (sconf->chan_config)
345  sconf->chan_config_info = get_bits(&gb, 16);
346  // TODO: use this to set avctx->channel_layout
347 
348 
349  // read channel sorting
350  if (sconf->chan_sort && avctx->channels > 1) {
351  int chan_pos_bits = av_ceil_log2(avctx->channels);
352  int bits_needed = avctx->channels * chan_pos_bits + 7;
353  if (get_bits_left(&gb) < bits_needed)
354  return -1;
355 
356  if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))
357  return AVERROR(ENOMEM);
358 
359  ctx->cs_switch = 1;
360 
361  for (i = 0; i < avctx->channels; i++) {
362  int idx;
363 
364  idx = get_bits(&gb, chan_pos_bits);
365  if (idx >= avctx->channels) {
366  av_log(avctx, AV_LOG_WARNING, "Invalid channel reordering.\n");
367  ctx->cs_switch = 0;
368  break;
369  }
370  sconf->chan_pos[idx] = i;
371  }
372 
373  align_get_bits(&gb);
374  }
375 
376 
377  // read fixed header and trailer sizes,
378  // if size = 0xFFFFFFFF then there is no data field!
379  if (get_bits_left(&gb) < 64)
380  return -1;
381 
382  header_size = get_bits_long(&gb, 32);
383  trailer_size = get_bits_long(&gb, 32);
384  if (header_size == 0xFFFFFFFF)
385  header_size = 0;
386  if (trailer_size == 0xFFFFFFFF)
387  trailer_size = 0;
388 
389  ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3;
390 
391 
392  // skip the header and trailer data
393  if (get_bits_left(&gb) < ht_size)
394  return -1;
395 
396  if (ht_size > INT32_MAX)
397  return -1;
398 
399  skip_bits_long(&gb, ht_size);
400 
401 
402  // initialize CRC calculation
403  if (sconf->crc_enabled) {
404  if (get_bits_left(&gb) < 32)
405  return -1;
406 
407  if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
408  ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
409  ctx->crc = 0xFFFFFFFF;
410  ctx->crc_org = ~get_bits_long(&gb, 32);
411  } else
412  skip_bits_long(&gb, 32);
413  }
414 
415 
416  // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)
417 
418  dprint_specific_config(ctx);
419 
420  return 0;
421 }
422 
423 
424 /** Check the ALSSpecificConfig for unsupported features.
425  */
426 static int check_specific_config(ALSDecContext *ctx)
427 {
428  ALSSpecificConfig *sconf = &ctx->sconf;
429  int error = 0;
430 
431  // report unsupported feature and set error value
432  #define MISSING_ERR(cond, str, errval) \
433  { \
434  if (cond) { \
435  av_log_missing_feature(ctx->avctx, str, 0); \
436  error = errval; \
437  } \
438  }
439 
440  MISSING_ERR(sconf->floating, "Floating point decoding", AVERROR_PATCHWELCOME);
441  MISSING_ERR(sconf->rlslms, "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME);
442 
443  return error;
444 }
445 
446 
447 /** Parse the bs_info field to extract the block partitioning used in
448  * block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.
449  */
450 static void parse_bs_info(const uint32_t bs_info, unsigned int n,
451  unsigned int div, unsigned int **div_blocks,
452  unsigned int *num_blocks)
453 {
454  if (n < 31 && ((bs_info << n) & 0x40000000)) {
455  // if the level is valid and the investigated bit n is set
456  // then recursively check both children at bits (2n+1) and (2n+2)
457  n *= 2;
458  div += 1;
459  parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);
460  parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);
461  } else {
462  // else the bit is not set or the last level has been reached
463  // (bit implicitly not set)
464  **div_blocks = div;
465  (*div_blocks)++;
466  (*num_blocks)++;
467  }
468 }
469 
470 
471 /** Read and decode a Rice codeword.
472  */
473 static int32_t decode_rice(GetBitContext *gb, unsigned int k)
474 {
475  int max = get_bits_left(gb) - k;
476  int q = get_unary(gb, 0, max);
477  int r = k ? get_bits1(gb) : !(q & 1);
478 
479  if (k > 1) {
480  q <<= (k - 1);
481  q += get_bits_long(gb, k - 1);
482  } else if (!k) {
483  q >>= 1;
484  }
485  return r ? q : ~q;
486 }
487 
488 
489 /** Convert PARCOR coefficient k to direct filter coefficient.
490  */
491 static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)
492 {
493  int i, j;
494 
495  for (i = 0, j = k - 1; i < j; i++, j--) {
496  int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
497  cof[j] += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);
498  cof[i] += tmp1;
499  }
500  if (i == j)
501  cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
502 
503  cof[k] = par[k];
504 }
505 
506 
507 /** Read block switching field if necessary and set actual block sizes.
508  * Also assure that the block sizes of the last frame correspond to the
509  * actual number of samples.
510  */
511 static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
512  uint32_t *bs_info)
513 {
514  ALSSpecificConfig *sconf = &ctx->sconf;
515  GetBitContext *gb = &ctx->gb;
516  unsigned int *ptr_div_blocks = div_blocks;
517  unsigned int b;
518 
519  if (sconf->block_switching) {
520  unsigned int bs_info_len = 1 << (sconf->block_switching + 2);
521  *bs_info = get_bits_long(gb, bs_info_len);
522  *bs_info <<= (32 - bs_info_len);
523  }
524 
525  ctx->num_blocks = 0;
526  parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);
527 
528  // The last frame may have an overdetermined block structure given in
529  // the bitstream. In that case the defined block structure would need
530  // more samples than available to be consistent.
531  // The block structure is actually used but the block sizes are adapted
532  // to fit the actual number of available samples.
533  // Example: 5 samples, 2nd level block sizes: 2 2 2 2.
534  // This results in the actual block sizes: 2 2 1 0.
535  // This is not specified in 14496-3 but actually done by the reference
536  // codec RM22 revision 2.
537  // This appears to happen in case of an odd number of samples in the last
538  // frame which is actually not allowed by the block length switching part
539  // of 14496-3.
540  // The ALS conformance files feature an odd number of samples in the last
541  // frame.
542 
543  for (b = 0; b < ctx->num_blocks; b++)
544  div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];
545 
546  if (ctx->cur_frame_length != ctx->sconf.frame_length) {
547  unsigned int remaining = ctx->cur_frame_length;
548 
549  for (b = 0; b < ctx->num_blocks; b++) {
550  if (remaining <= div_blocks[b]) {
551  div_blocks[b] = remaining;
552  ctx->num_blocks = b + 1;
553  break;
554  }
555 
556  remaining -= div_blocks[b];
557  }
558  }
559 }
560 
561 
562 /** Read the block data for a constant block
563  */
564 static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
565 {
566  ALSSpecificConfig *sconf = &ctx->sconf;
567  AVCodecContext *avctx = ctx->avctx;
568  GetBitContext *gb = &ctx->gb;
569 
570  if (bd->block_length <= 0)
571  return AVERROR_INVALIDDATA;
572 
573  *bd->raw_samples = 0;
574  *bd->const_block = get_bits1(gb); // 1 = constant value, 0 = zero block (silence)
575  bd->js_blocks = get_bits1(gb);
576 
577  // skip 5 reserved bits
578  skip_bits(gb, 5);
579 
580  if (*bd->const_block) {
581  unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;
582  *bd->raw_samples = get_sbits_long(gb, const_val_bits);
583  }
584 
585  // ensure constant block decoding by reusing this field
586  *bd->const_block = 1;
587 
588  return 0;
589 }
590 
591 
592 /** Decode the block data for a constant block
593  */
594 static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
595 {
596  int smp = bd->block_length - 1;
597  int32_t val = *bd->raw_samples;
598  int32_t *dst = bd->raw_samples + 1;
599 
600  // write raw samples into buffer
601  for (; smp; smp--)
602  *dst++ = val;
603 }
604 
605 
606 /** Read the block data for a non-constant block
607  */
608 static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
609 {
610  ALSSpecificConfig *sconf = &ctx->sconf;
611  AVCodecContext *avctx = ctx->avctx;
612  GetBitContext *gb = &ctx->gb;
613  unsigned int k;
614  unsigned int s[8];
615  unsigned int sx[8];
616  unsigned int sub_blocks, log2_sub_blocks, sb_length;
617  unsigned int start = 0;
618  unsigned int opt_order;
619  int sb;
620  int32_t *quant_cof = bd->quant_cof;
621  int32_t *current_res;
622 
623 
624  // ensure variable block decoding by reusing this field
625  *bd->const_block = 0;
626 
627  *bd->opt_order = 1;
628  bd->js_blocks = get_bits1(gb);
629 
630  opt_order = *bd->opt_order;
631 
632  // determine the number of subblocks for entropy decoding
633  if (!sconf->bgmc && !sconf->sb_part) {
634  log2_sub_blocks = 0;
635  } else {
636  if (sconf->bgmc && sconf->sb_part)
637  log2_sub_blocks = get_bits(gb, 2);
638  else
639  log2_sub_blocks = 2 * get_bits1(gb);
640  }
641 
642  sub_blocks = 1 << log2_sub_blocks;
643 
644  // do not continue in case of a damaged stream since
645  // block_length must be evenly divisible by sub_blocks
646  if (bd->block_length & (sub_blocks - 1)) {
647  av_log(avctx, AV_LOG_WARNING,
648  "Block length is not evenly divisible by the number of subblocks.\n");
649  return -1;
650  }
651 
652  sb_length = bd->block_length >> log2_sub_blocks;
653 
654  if (sconf->bgmc) {
655  s[0] = get_bits(gb, 8 + (sconf->resolution > 1));
656  for (k = 1; k < sub_blocks; k++)
657  s[k] = s[k - 1] + decode_rice(gb, 2);
658 
659  for (k = 0; k < sub_blocks; k++) {
660  sx[k] = s[k] & 0x0F;
661  s [k] >>= 4;
662  }
663  } else {
664  s[0] = get_bits(gb, 4 + (sconf->resolution > 1));
665  for (k = 1; k < sub_blocks; k++)
666  s[k] = s[k - 1] + decode_rice(gb, 0);
667  }
668  for (k = 1; k < sub_blocks; k++)
669  if (s[k] > 32) {
670  av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");
671  return AVERROR_INVALIDDATA;
672  }
673 
674  if (get_bits1(gb))
675  *bd->shift_lsbs = get_bits(gb, 4) + 1;
676 
677  *bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || *bd->shift_lsbs;
678 
679 
680  if (!sconf->rlslms) {
681  if (sconf->adapt_order) {
682  int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,
683  2, sconf->max_order + 1));
684  *bd->opt_order = get_bits(gb, opt_order_length);
685  if (*bd->opt_order > sconf->max_order) {
686  *bd->opt_order = sconf->max_order;
687  av_log(avctx, AV_LOG_ERROR, "Predictor order too large.\n");
688  return AVERROR_INVALIDDATA;
689  }
690  } else {
691  *bd->opt_order = sconf->max_order;
692  }
693 
694  opt_order = *bd->opt_order;
695 
696  if (opt_order) {
697  int add_base;
698 
699  if (sconf->coef_table == 3) {
700  add_base = 0x7F;
701 
702  // read coefficient 0
703  quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];
704 
705  // read coefficient 1
706  if (opt_order > 1)
707  quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];
708 
709  // read coefficients 2 to opt_order
710  for (k = 2; k < opt_order; k++)
711  quant_cof[k] = get_bits(gb, 7);
712  } else {
713  int k_max;
714  add_base = 1;
715 
716  // read coefficient 0 to 19
717  k_max = FFMIN(opt_order, 20);
718  for (k = 0; k < k_max; k++) {
719  int rice_param = parcor_rice_table[sconf->coef_table][k][1];
720  int offset = parcor_rice_table[sconf->coef_table][k][0];
721  quant_cof[k] = decode_rice(gb, rice_param) + offset;
722  if (quant_cof[k] < -64 || quant_cof[k] > 63) {
723  av_log(avctx, AV_LOG_ERROR, "quant_cof %d is out of range.\n", quant_cof[k]);
724  return AVERROR_INVALIDDATA;
725  }
726  }
727 
728  // read coefficients 20 to 126
729  k_max = FFMIN(opt_order, 127);
730  for (; k < k_max; k++)
731  quant_cof[k] = decode_rice(gb, 2) + (k & 1);
732 
733  // read coefficients 127 to opt_order
734  for (; k < opt_order; k++)
735  quant_cof[k] = decode_rice(gb, 1);
736 
737  quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];
738 
739  if (opt_order > 1)
740  quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];
741  }
742 
743  for (k = 2; k < opt_order; k++)
744  quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);
745  }
746  }
747 
748  // read LTP gain and lag values
749  if (sconf->long_term_prediction) {
750  *bd->use_ltp = get_bits1(gb);
751 
752  if (*bd->use_ltp) {
753  int r, c;
754 
755  bd->ltp_gain[0] = decode_rice(gb, 1) << 3;
756  bd->ltp_gain[1] = decode_rice(gb, 2) << 3;
757 
758  r = get_unary(gb, 0, 3);
759  c = get_bits(gb, 2);
760  bd->ltp_gain[2] = ltp_gain_values[r][c];
761 
762  bd->ltp_gain[3] = decode_rice(gb, 2) << 3;
763  bd->ltp_gain[4] = decode_rice(gb, 1) << 3;
764 
765  *bd->ltp_lag = get_bits(gb, ctx->ltp_lag_length);
766  *bd->ltp_lag += FFMAX(4, opt_order + 1);
767  }
768  }
769 
770  // read first value and residuals in case of a random access block
771  if (bd->ra_block) {
772  if (opt_order)
773  bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
774  if (opt_order > 1)
775  bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));
776  if (opt_order > 2)
777  bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));
778 
779  start = FFMIN(opt_order, 3);
780  }
781 
782  // read all residuals
783  if (sconf->bgmc) {
784  int delta[8];
785  unsigned int k [8];
786  unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5);
787 
788  // read most significant bits
789  unsigned int high;
790  unsigned int low;
791  unsigned int value;
792 
793  ff_bgmc_decode_init(gb, &high, &low, &value);
794 
795  current_res = bd->raw_samples + start;
796 
797  for (sb = 0; sb < sub_blocks; sb++) {
798  unsigned int sb_len = sb_length - (sb ? 0 : start);
799 
800  k [sb] = s[sb] > b ? s[sb] - b : 0;
801  delta[sb] = 5 - s[sb] + k[sb];
802 
803  ff_bgmc_decode(gb, sb_len, current_res,
804  delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);
805 
806  current_res += sb_len;
807  }
808 
809  ff_bgmc_decode_end(gb);
810 
811 
812  // read least significant bits and tails
813  current_res = bd->raw_samples + start;
814 
815  for (sb = 0; sb < sub_blocks; sb++, start = 0) {
816  unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]];
817  unsigned int cur_k = k[sb];
818  unsigned int cur_s = s[sb];
819 
820  for (; start < sb_length; start++) {
821  int32_t res = *current_res;
822 
823  if (res == cur_tail_code) {
824  unsigned int max_msb = (2 + (sx[sb] > 2) + (sx[sb] > 10))
825  << (5 - delta[sb]);
826 
827  res = decode_rice(gb, cur_s);
828 
829  if (res >= 0) {
830  res += (max_msb ) << cur_k;
831  } else {
832  res -= (max_msb - 1) << cur_k;
833  }
834  } else {
835  if (res > cur_tail_code)
836  res--;
837 
838  if (res & 1)
839  res = -res;
840 
841  res >>= 1;
842 
843  if (cur_k) {
844  res <<= cur_k;
845  res |= get_bits_long(gb, cur_k);
846  }
847  }
848 
849  *current_res++ = res;
850  }
851  }
852  } else {
853  current_res = bd->raw_samples + start;
854 
855  for (sb = 0; sb < sub_blocks; sb++, start = 0)
856  for (; start < sb_length; start++)
857  *current_res++ = decode_rice(gb, s[sb]);
858  }
859 
860  if (!sconf->mc_coding || ctx->js_switch)
861  align_get_bits(gb);
862 
863  return 0;
864 }
865 
866 
867 /** Decode the block data for a non-constant block
868  */
869 static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
870 {
871  ALSSpecificConfig *sconf = &ctx->sconf;
872  unsigned int block_length = bd->block_length;
873  unsigned int smp = 0;
874  unsigned int k;
875  int opt_order = *bd->opt_order;
876  int sb;
877  int64_t y;
878  int32_t *quant_cof = bd->quant_cof;
879  int32_t *lpc_cof = bd->lpc_cof;
880  int32_t *raw_samples = bd->raw_samples;
881  int32_t *raw_samples_end = bd->raw_samples + bd->block_length;
882  int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;
883 
884  // reverse long-term prediction
885  if (*bd->use_ltp) {
886  int ltp_smp;
887 
888  for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {
889  int center = ltp_smp - *bd->ltp_lag;
890  int begin = FFMAX(0, center - 2);
891  int end = center + 3;
892  int tab = 5 - (end - begin);
893  int base;
894 
895  y = 1 << 6;
896 
897  for (base = begin; base < end; base++, tab++)
898  y += MUL64(bd->ltp_gain[tab], raw_samples[base]);
899 
900  raw_samples[ltp_smp] += y >> 7;
901  }
902  }
903 
904  // reconstruct all samples from residuals
905  if (bd->ra_block) {
906  for (smp = 0; smp < opt_order; smp++) {
907  y = 1 << 19;
908 
909  for (sb = 0; sb < smp; sb++)
910  y += MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);
911 
912  *raw_samples++ -= y >> 20;
913  parcor_to_lpc(smp, quant_cof, lpc_cof);
914  }
915  } else {
916  for (k = 0; k < opt_order; k++)
917  parcor_to_lpc(k, quant_cof, lpc_cof);
918 
919  // store previous samples in case that they have to be altered
920  if (*bd->store_prev_samples)
921  memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,
922  sizeof(*bd->prev_raw_samples) * sconf->max_order);
923 
924  // reconstruct difference signal for prediction (joint-stereo)
925  if (bd->js_blocks && bd->raw_other) {
926  int32_t *left, *right;
927 
928  if (bd->raw_other > raw_samples) { // D = R - L
929  left = raw_samples;
930  right = bd->raw_other;
931  } else { // D = R - L
932  left = bd->raw_other;
933  right = raw_samples;
934  }
935 
936  for (sb = -1; sb >= -sconf->max_order; sb--)
937  raw_samples[sb] = right[sb] - left[sb];
938  }
939 
940  // reconstruct shifted signal
941  if (*bd->shift_lsbs)
942  for (sb = -1; sb >= -sconf->max_order; sb--)
943  raw_samples[sb] >>= *bd->shift_lsbs;
944  }
945 
946  // reverse linear prediction coefficients for efficiency
947  lpc_cof = lpc_cof + opt_order;
948 
949  for (sb = 0; sb < opt_order; sb++)
950  lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];
951 
952  // reconstruct raw samples
953  raw_samples = bd->raw_samples + smp;
954  lpc_cof = lpc_cof_reversed + opt_order;
955 
956  for (; raw_samples < raw_samples_end; raw_samples++) {
957  y = 1 << 19;
958 
959  for (sb = -opt_order; sb < 0; sb++)
960  y += MUL64(lpc_cof[sb], raw_samples[sb]);
961 
962  *raw_samples -= y >> 20;
963  }
964 
965  raw_samples = bd->raw_samples;
966 
967  // restore previous samples in case that they have been altered
968  if (*bd->store_prev_samples)
969  memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,
970  sizeof(*raw_samples) * sconf->max_order);
971 
972  return 0;
973 }
974 
975 
976 /** Read the block data.
977  */
978 static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
979 {
980  GetBitContext *gb = &ctx->gb;
981  int ret;
982 
983  *bd->shift_lsbs = 0;
984  // read block type flag and read the samples accordingly
985  if (get_bits1(gb)) {
986  if ((ret = read_var_block_data(ctx, bd)) < 0)
987  return ret;
988  } else {
989  if ((ret = read_const_block_data(ctx, bd)) < 0)
990  return ret;
991  }
992 
993  return 0;
994 }
995 
996 
997 /** Decode the block data.
998  */
999 static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1000 {
1001  unsigned int smp;
1002 
1003  // read block type flag and read the samples accordingly
1004  if (*bd->const_block)
1005  decode_const_block_data(ctx, bd);
1006  else if (decode_var_block_data(ctx, bd))
1007  return -1;
1008 
1009  // TODO: read RLSLMS extension data
1010 
1011  if (*bd->shift_lsbs)
1012  for (smp = 0; smp < bd->block_length; smp++)
1013  bd->raw_samples[smp] <<= *bd->shift_lsbs;
1014 
1015  return 0;
1016 }
1017 
1018 
1019 /** Read and decode block data successively.
1020  */
1021 static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1022 {
1023  int ret;
1024 
1025  ret = read_block(ctx, bd);
1026 
1027  if (ret)
1028  return ret;
1029 
1030  ret = decode_block(ctx, bd);
1031 
1032  return ret;
1033 }
1034 
1035 
1036 /** Compute the number of samples left to decode for the current frame and
1037  * sets these samples to zero.
1038  */
1039 static void zero_remaining(unsigned int b, unsigned int b_max,
1040  const unsigned int *div_blocks, int32_t *buf)
1041 {
1042  unsigned int count = 0;
1043 
1044  while (b < b_max)
1045  count += div_blocks[b++];
1046 
1047  if (count)
1048  memset(buf, 0, sizeof(*buf) * count);
1049 }
1050 
1051 
1052 /** Decode blocks independently.
1053  */
1054 static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,
1055  unsigned int c, const unsigned int *div_blocks,
1056  unsigned int *js_blocks)
1057 {
1058  unsigned int b;
1059  ALSBlockData bd = { 0 };
1060 
1061  bd.ra_block = ra_frame;
1062  bd.const_block = ctx->const_block;
1063  bd.shift_lsbs = ctx->shift_lsbs;
1064  bd.opt_order = ctx->opt_order;
1065  bd.store_prev_samples = ctx->store_prev_samples;
1066  bd.use_ltp = ctx->use_ltp;
1067  bd.ltp_lag = ctx->ltp_lag;
1068  bd.ltp_gain = ctx->ltp_gain[0];
1069  bd.quant_cof = ctx->quant_cof[0];
1070  bd.lpc_cof = ctx->lpc_cof[0];
1071  bd.prev_raw_samples = ctx->prev_raw_samples;
1072  bd.raw_samples = ctx->raw_samples[c];
1073 
1074 
1075  for (b = 0; b < ctx->num_blocks; b++) {
1076  bd.block_length = div_blocks[b];
1077 
1078  if (read_decode_block(ctx, &bd)) {
1079  // damaged block, write zero for the rest of the frame
1080  zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);
1081  return -1;
1082  }
1083  bd.raw_samples += div_blocks[b];
1084  bd.ra_block = 0;
1085  }
1086 
1087  return 0;
1088 }
1089 
1090 
1091 /** Decode blocks dependently.
1092  */
1093 static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
1094  unsigned int c, const unsigned int *div_blocks,
1095  unsigned int *js_blocks)
1096 {
1097  ALSSpecificConfig *sconf = &ctx->sconf;
1098  unsigned int offset = 0;
1099  unsigned int b;
1100  ALSBlockData bd[2] = { { 0 } };
1101 
1102  bd[0].ra_block = ra_frame;
1103  bd[0].const_block = ctx->const_block;
1104  bd[0].shift_lsbs = ctx->shift_lsbs;
1105  bd[0].opt_order = ctx->opt_order;
1106  bd[0].store_prev_samples = ctx->store_prev_samples;
1107  bd[0].use_ltp = ctx->use_ltp;
1108  bd[0].ltp_lag = ctx->ltp_lag;
1109  bd[0].ltp_gain = ctx->ltp_gain[0];
1110  bd[0].quant_cof = ctx->quant_cof[0];
1111  bd[0].lpc_cof = ctx->lpc_cof[0];
1112  bd[0].prev_raw_samples = ctx->prev_raw_samples;
1113  bd[0].js_blocks = *js_blocks;
1114 
1115  bd[1].ra_block = ra_frame;
1116  bd[1].const_block = ctx->const_block;
1117  bd[1].shift_lsbs = ctx->shift_lsbs;
1118  bd[1].opt_order = ctx->opt_order;
1119  bd[1].store_prev_samples = ctx->store_prev_samples;
1120  bd[1].use_ltp = ctx->use_ltp;
1121  bd[1].ltp_lag = ctx->ltp_lag;
1122  bd[1].ltp_gain = ctx->ltp_gain[0];
1123  bd[1].quant_cof = ctx->quant_cof[0];
1124  bd[1].lpc_cof = ctx->lpc_cof[0];
1125  bd[1].prev_raw_samples = ctx->prev_raw_samples;
1126  bd[1].js_blocks = *(js_blocks + 1);
1127 
1128  // decode all blocks
1129  for (b = 0; b < ctx->num_blocks; b++) {
1130  unsigned int s;
1131 
1132  bd[0].block_length = div_blocks[b];
1133  bd[1].block_length = div_blocks[b];
1134 
1135  bd[0].raw_samples = ctx->raw_samples[c ] + offset;
1136  bd[1].raw_samples = ctx->raw_samples[c + 1] + offset;
1137 
1138  bd[0].raw_other = bd[1].raw_samples;
1139  bd[1].raw_other = bd[0].raw_samples;
1140 
1141  if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {
1142  // damaged block, write zero for the rest of the frame
1143  zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);
1144  zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);
1145  return -1;
1146  }
1147 
1148  // reconstruct joint-stereo blocks
1149  if (bd[0].js_blocks) {
1150  if (bd[1].js_blocks)
1151  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");
1152 
1153  for (s = 0; s < div_blocks[b]; s++)
1154  bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];
1155  } else if (bd[1].js_blocks) {
1156  for (s = 0; s < div_blocks[b]; s++)
1157  bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];
1158  }
1159 
1160  offset += div_blocks[b];
1161  bd[0].ra_block = 0;
1162  bd[1].ra_block = 0;
1163  }
1164 
1165  // store carryover raw samples,
1166  // the others channel raw samples are stored by the calling function.
1167  memmove(ctx->raw_samples[c] - sconf->max_order,
1168  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1169  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1170 
1171  return 0;
1172 }
1173 
1174 
1175 /** Read the channel data.
1176  */
1177 static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)
1178 {
1179  GetBitContext *gb = &ctx->gb;
1180  ALSChannelData *current = cd;
1181  unsigned int channels = ctx->avctx->channels;
1182  int entries = 0;
1183 
1184  while (entries < channels && !(current->stop_flag = get_bits1(gb))) {
1185  current->master_channel = get_bits_long(gb, av_ceil_log2(channels));
1186 
1187  if (current->master_channel >= channels) {
1188  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n");
1189  return -1;
1190  }
1191 
1192  if (current->master_channel != c) {
1193  current->time_diff_flag = get_bits1(gb);
1194  current->weighting[0] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1195  current->weighting[1] = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 31)];
1196  current->weighting[2] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1197 
1198  if (current->time_diff_flag) {
1199  current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1200  current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1201  current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1202 
1203  current->time_diff_sign = get_bits1(gb);
1204  current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;
1205  }
1206  }
1207 
1208  current++;
1209  entries++;
1210  }
1211 
1212  if (entries == channels) {
1213  av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data.\n");
1214  return -1;
1215  }
1216 
1217  align_get_bits(gb);
1218  return 0;
1219 }
1220 
1221 
1222 /** Recursively reverts the inter-channel correlation for a block.
1223  */
1224 static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,
1225  ALSChannelData **cd, int *reverted,
1226  unsigned int offset, int c)
1227 {
1228  ALSChannelData *ch = cd[c];
1229  unsigned int dep = 0;
1230  unsigned int channels = ctx->avctx->channels;
1231 
1232  if (reverted[c])
1233  return 0;
1234 
1235  reverted[c] = 1;
1236 
1237  while (dep < channels && !ch[dep].stop_flag) {
1238  revert_channel_correlation(ctx, bd, cd, reverted, offset,
1239  ch[dep].master_channel);
1240 
1241  dep++;
1242  }
1243 
1244  if (dep == channels) {
1245  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n");
1246  return -1;
1247  }
1248 
1249  bd->const_block = ctx->const_block + c;
1250  bd->shift_lsbs = ctx->shift_lsbs + c;
1251  bd->opt_order = ctx->opt_order + c;
1252  bd->store_prev_samples = ctx->store_prev_samples + c;
1253  bd->use_ltp = ctx->use_ltp + c;
1254  bd->ltp_lag = ctx->ltp_lag + c;
1255  bd->ltp_gain = ctx->ltp_gain[c];
1256  bd->lpc_cof = ctx->lpc_cof[c];
1257  bd->quant_cof = ctx->quant_cof[c];
1258  bd->raw_samples = ctx->raw_samples[c] + offset;
1259 
1260  dep = 0;
1261  while (!ch[dep].stop_flag) {
1262  unsigned int smp;
1263  unsigned int begin = 1;
1264  unsigned int end = bd->block_length - 1;
1265  int64_t y;
1266  int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;
1267 
1268  if (ch[dep].time_diff_flag) {
1269  int t = ch[dep].time_diff_index;
1270 
1271  if (ch[dep].time_diff_sign) {
1272  t = -t;
1273  begin -= t;
1274  } else {
1275  end -= t;
1276  }
1277 
1278  for (smp = begin; smp < end; smp++) {
1279  y = (1 << 6) +
1280  MUL64(ch[dep].weighting[0], master[smp - 1 ]) +
1281  MUL64(ch[dep].weighting[1], master[smp ]) +
1282  MUL64(ch[dep].weighting[2], master[smp + 1 ]) +
1283  MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +
1284  MUL64(ch[dep].weighting[4], master[smp + t]) +
1285  MUL64(ch[dep].weighting[5], master[smp + 1 + t]);
1286 
1287  bd->raw_samples[smp] += y >> 7;
1288  }
1289  } else {
1290  for (smp = begin; smp < end; smp++) {
1291  y = (1 << 6) +
1292  MUL64(ch[dep].weighting[0], master[smp - 1]) +
1293  MUL64(ch[dep].weighting[1], master[smp ]) +
1294  MUL64(ch[dep].weighting[2], master[smp + 1]);
1295 
1296  bd->raw_samples[smp] += y >> 7;
1297  }
1298  }
1299 
1300  dep++;
1301  }
1302 
1303  return 0;
1304 }
1305 
1306 
1307 /** Read the frame data.
1308  */
1309 static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
1310 {
1311  ALSSpecificConfig *sconf = &ctx->sconf;
1312  AVCodecContext *avctx = ctx->avctx;
1313  GetBitContext *gb = &ctx->gb;
1314  unsigned int div_blocks[32]; ///< block sizes.
1315  unsigned int c;
1316  unsigned int js_blocks[2];
1317 
1318  uint32_t bs_info = 0;
1319 
1320  // skip the size of the ra unit if present in the frame
1321  if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)
1322  skip_bits_long(gb, 32);
1323 
1324  if (sconf->mc_coding && sconf->joint_stereo) {
1325  ctx->js_switch = get_bits1(gb);
1326  align_get_bits(gb);
1327  }
1328 
1329  if (!sconf->mc_coding || ctx->js_switch) {
1330  int independent_bs = !sconf->joint_stereo;
1331 
1332  for (c = 0; c < avctx->channels; c++) {
1333  js_blocks[0] = 0;
1334  js_blocks[1] = 0;
1335 
1336  get_block_sizes(ctx, div_blocks, &bs_info);
1337 
1338  // if joint_stereo and block_switching is set, independent decoding
1339  // is signaled via the first bit of bs_info
1340  if (sconf->joint_stereo && sconf->block_switching)
1341  if (bs_info >> 31)
1342  independent_bs = 2;
1343 
1344  // if this is the last channel, it has to be decoded independently
1345  if (c == avctx->channels - 1)
1346  independent_bs = 1;
1347 
1348  if (independent_bs) {
1349  if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))
1350  return -1;
1351 
1352  independent_bs--;
1353  } else {
1354  if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))
1355  return -1;
1356 
1357  c++;
1358  }
1359 
1360  // store carryover raw samples
1361  memmove(ctx->raw_samples[c] - sconf->max_order,
1362  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1363  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1364  }
1365  } else { // multi-channel coding
1366  ALSBlockData bd = { 0 };
1367  int b, ret;
1368  int *reverted_channels = ctx->reverted_channels;
1369  unsigned int offset = 0;
1370 
1371  for (c = 0; c < avctx->channels; c++)
1372  if (ctx->chan_data[c] < ctx->chan_data_buffer) {
1373  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n");
1374  return -1;
1375  }
1376 
1377  memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);
1378 
1379  bd.ra_block = ra_frame;
1380  bd.prev_raw_samples = ctx->prev_raw_samples;
1381 
1382  get_block_sizes(ctx, div_blocks, &bs_info);
1383 
1384  for (b = 0; b < ctx->num_blocks; b++) {
1385  bd.block_length = div_blocks[b];
1386 
1387  for (c = 0; c < avctx->channels; c++) {
1388  bd.const_block = ctx->const_block + c;
1389  bd.shift_lsbs = ctx->shift_lsbs + c;
1390  bd.opt_order = ctx->opt_order + c;
1391  bd.store_prev_samples = ctx->store_prev_samples + c;
1392  bd.use_ltp = ctx->use_ltp + c;
1393  bd.ltp_lag = ctx->ltp_lag + c;
1394  bd.ltp_gain = ctx->ltp_gain[c];
1395  bd.lpc_cof = ctx->lpc_cof[c];
1396  bd.quant_cof = ctx->quant_cof[c];
1397  bd.raw_samples = ctx->raw_samples[c] + offset;
1398  bd.raw_other = NULL;
1399 
1400  if ((ret = read_block(ctx, &bd)) < 0)
1401  return ret;
1402  if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)
1403  return ret;
1404  }
1405 
1406  for (c = 0; c < avctx->channels; c++)
1407  if (revert_channel_correlation(ctx, &bd, ctx->chan_data,
1408  reverted_channels, offset, c))
1409  return -1;
1410 
1411  for (c = 0; c < avctx->channels; c++) {
1412  bd.const_block = ctx->const_block + c;
1413  bd.shift_lsbs = ctx->shift_lsbs + c;
1414  bd.opt_order = ctx->opt_order + c;
1415  bd.store_prev_samples = ctx->store_prev_samples + c;
1416  bd.use_ltp = ctx->use_ltp + c;
1417  bd.ltp_lag = ctx->ltp_lag + c;
1418  bd.ltp_gain = ctx->ltp_gain[c];
1419  bd.lpc_cof = ctx->lpc_cof[c];
1420  bd.quant_cof = ctx->quant_cof[c];
1421  bd.raw_samples = ctx->raw_samples[c] + offset;
1422 
1423  if ((ret = decode_block(ctx, &bd)) < 0)
1424  return ret;
1425  }
1426 
1427  memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));
1428  offset += div_blocks[b];
1429  bd.ra_block = 0;
1430  }
1431 
1432  // store carryover raw samples
1433  for (c = 0; c < avctx->channels; c++)
1434  memmove(ctx->raw_samples[c] - sconf->max_order,
1435  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1436  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1437  }
1438 
1439  // TODO: read_diff_float_data
1440 
1441  return 0;
1442 }
1443 
1444 
1445 /** Decode an ALS frame.
1446  */
1447 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
1448  AVPacket *avpkt)
1449 {
1450  ALSDecContext *ctx = avctx->priv_data;
1451  ALSSpecificConfig *sconf = &ctx->sconf;
1452  const uint8_t *buffer = avpkt->data;
1453  int buffer_size = avpkt->size;
1454  int invalid_frame, ret;
1455  unsigned int c, sample, ra_frame, bytes_read, shift;
1456 
1457  init_get_bits(&ctx->gb, buffer, buffer_size * 8);
1458 
1459  // In the case that the distance between random access frames is set to zero
1460  // (sconf->ra_distance == 0) no frame is treated as a random access frame.
1461  // For the first frame, if prediction is used, all samples used from the
1462  // previous frame are assumed to be zero.
1463  ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);
1464 
1465  // the last frame to decode might have a different length
1466  if (sconf->samples != 0xFFFFFFFF)
1467  ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,
1468  sconf->frame_length);
1469  else
1470  ctx->cur_frame_length = sconf->frame_length;
1471 
1472  // decode the frame data
1473  if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)
1474  av_log(ctx->avctx, AV_LOG_WARNING,
1475  "Reading frame data failed. Skipping RA unit.\n");
1476 
1477  ctx->frame_id++;
1478 
1479  /* get output buffer */
1480  ctx->frame.nb_samples = ctx->cur_frame_length;
1481  if ((ret = ff_get_buffer(avctx, &ctx->frame)) < 0) {
1482  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
1483  return ret;
1484  }
1485 
1486  // transform decoded frame into output format
1487  #define INTERLEAVE_OUTPUT(bps) \
1488  { \
1489  int##bps##_t *dest = (int##bps##_t*)ctx->frame.data[0]; \
1490  shift = bps - ctx->avctx->bits_per_raw_sample; \
1491  if (!ctx->cs_switch) { \
1492  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1493  for (c = 0; c < avctx->channels; c++) \
1494  *dest++ = ctx->raw_samples[c][sample] << shift; \
1495  } else { \
1496  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1497  for (c = 0; c < avctx->channels; c++) \
1498  *dest++ = ctx->raw_samples[sconf->chan_pos[c]][sample] << shift; \
1499  } \
1500  }
1501 
1502  if (ctx->avctx->bits_per_raw_sample <= 16) {
1503  INTERLEAVE_OUTPUT(16)
1504  } else {
1505  INTERLEAVE_OUTPUT(32)
1506  }
1507 
1508  // update CRC
1509  if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1510  int swap = HAVE_BIGENDIAN != sconf->msb_first;
1511 
1512  if (ctx->avctx->bits_per_raw_sample == 24) {
1513  int32_t *src = (int32_t *)ctx->frame.data[0];
1514 
1515  for (sample = 0;
1516  sample < ctx->cur_frame_length * avctx->channels;
1517  sample++) {
1518  int32_t v;
1519 
1520  if (swap)
1521  v = av_bswap32(src[sample]);
1522  else
1523  v = src[sample];
1524  if (!HAVE_BIGENDIAN)
1525  v >>= 8;
1526 
1527  ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);
1528  }
1529  } else {
1530  uint8_t *crc_source;
1531 
1532  if (swap) {
1533  if (ctx->avctx->bits_per_raw_sample <= 16) {
1534  int16_t *src = (int16_t*) ctx->frame.data[0];
1535  int16_t *dest = (int16_t*) ctx->crc_buffer;
1536  for (sample = 0;
1537  sample < ctx->cur_frame_length * avctx->channels;
1538  sample++)
1539  *dest++ = av_bswap16(src[sample]);
1540  } else {
1541  ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,
1542  (uint32_t *)ctx->frame.data[0],
1543  ctx->cur_frame_length * avctx->channels);
1544  }
1545  crc_source = ctx->crc_buffer;
1546  } else {
1547  crc_source = ctx->frame.data[0];
1548  }
1549 
1550  ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,
1551  ctx->cur_frame_length * avctx->channels *
1552  av_get_bytes_per_sample(avctx->sample_fmt));
1553  }
1554 
1555 
1556  // check CRC sums if this is the last frame
1557  if (ctx->cur_frame_length != sconf->frame_length &&
1558  ctx->crc_org != ctx->crc) {
1559  av_log(avctx, AV_LOG_ERROR, "CRC error.\n");
1560  }
1561  }
1562 
1563  *got_frame_ptr = 1;
1564  *(AVFrame *)data = ctx->frame;
1565 
1566 
1567  bytes_read = invalid_frame ? buffer_size :
1568  (get_bits_count(&ctx->gb) + 7) >> 3;
1569 
1570  return bytes_read;
1571 }
1572 
1573 
1574 /** Uninitialize the ALS decoder.
1575  */
1576 static av_cold int decode_end(AVCodecContext *avctx)
1577 {
1578  ALSDecContext *ctx = avctx->priv_data;
1579 
1580  av_freep(&ctx->sconf.chan_pos);
1581 
1582  ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);
1583 
1584  av_freep(&ctx->const_block);
1585  av_freep(&ctx->shift_lsbs);
1586  av_freep(&ctx->opt_order);
1587  av_freep(&ctx->store_prev_samples);
1588  av_freep(&ctx->use_ltp);
1589  av_freep(&ctx->ltp_lag);
1590  av_freep(&ctx->ltp_gain);
1591  av_freep(&ctx->ltp_gain_buffer);
1592  av_freep(&ctx->quant_cof);
1593  av_freep(&ctx->lpc_cof);
1594  av_freep(&ctx->quant_cof_buffer);
1595  av_freep(&ctx->lpc_cof_buffer);
1596  av_freep(&ctx->lpc_cof_reversed_buffer);
1597  av_freep(&ctx->prev_raw_samples);
1598  av_freep(&ctx->raw_samples);
1599  av_freep(&ctx->raw_buffer);
1600  av_freep(&ctx->chan_data);
1601  av_freep(&ctx->chan_data_buffer);
1602  av_freep(&ctx->reverted_channels);
1603  av_freep(&ctx->crc_buffer);
1604 
1605  return 0;
1606 }
1607 
1608 
1609 /** Initialize the ALS decoder.
1610  */
1611 static av_cold int decode_init(AVCodecContext *avctx)
1612 {
1613  unsigned int c;
1614  unsigned int channel_size;
1615  int num_buffers;
1616  ALSDecContext *ctx = avctx->priv_data;
1617  ALSSpecificConfig *sconf = &ctx->sconf;
1618  ctx->avctx = avctx;
1619 
1620  if (!avctx->extradata) {
1621  av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");
1622  return -1;
1623  }
1624 
1625  if (read_specific_config(ctx)) {
1626  av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");
1627  decode_end(avctx);
1628  return -1;
1629  }
1630 
1631  if (check_specific_config(ctx)) {
1632  decode_end(avctx);
1633  return -1;
1634  }
1635 
1636  if (sconf->bgmc)
1637  ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);
1638 
1639  if (sconf->floating) {
1640  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
1641  avctx->bits_per_raw_sample = 32;
1642  } else {
1643  avctx->sample_fmt = sconf->resolution > 1
1644  ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
1645  avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;
1646  }
1647 
1648  // set maximum Rice parameter for progressive decoding based on resolution
1649  // This is not specified in 14496-3 but actually done by the reference
1650  // codec RM22 revision 2.
1651  ctx->s_max = sconf->resolution > 1 ? 31 : 15;
1652 
1653  // set lag value for long-term prediction
1654  ctx->ltp_lag_length = 8 + (avctx->sample_rate >= 96000) +
1655  (avctx->sample_rate >= 192000);
1656 
1657  // allocate quantized parcor coefficient buffer
1658  num_buffers = sconf->mc_coding ? avctx->channels : 1;
1659 
1660  ctx->quant_cof = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);
1661  ctx->lpc_cof = av_malloc(sizeof(*ctx->lpc_cof) * num_buffers);
1662  ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *
1663  num_buffers * sconf->max_order);
1664  ctx->lpc_cof_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *
1665  num_buffers * sconf->max_order);
1666  ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *
1667  sconf->max_order);
1668 
1669  if (!ctx->quant_cof || !ctx->lpc_cof ||
1670  !ctx->quant_cof_buffer || !ctx->lpc_cof_buffer ||
1671  !ctx->lpc_cof_reversed_buffer) {
1672  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1673  return AVERROR(ENOMEM);
1674  }
1675 
1676  // assign quantized parcor coefficient buffers
1677  for (c = 0; c < num_buffers; c++) {
1678  ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;
1679  ctx->lpc_cof[c] = ctx->lpc_cof_buffer + c * sconf->max_order;
1680  }
1681 
1682  // allocate and assign lag and gain data buffer for ltp mode
1683  ctx->const_block = av_malloc (sizeof(*ctx->const_block) * num_buffers);
1684  ctx->shift_lsbs = av_malloc (sizeof(*ctx->shift_lsbs) * num_buffers);
1685  ctx->opt_order = av_malloc (sizeof(*ctx->opt_order) * num_buffers);
1686  ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);
1687  ctx->use_ltp = av_mallocz(sizeof(*ctx->use_ltp) * num_buffers);
1688  ctx->ltp_lag = av_malloc (sizeof(*ctx->ltp_lag) * num_buffers);
1689  ctx->ltp_gain = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);
1690  ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *
1691  num_buffers * 5);
1692 
1693  if (!ctx->const_block || !ctx->shift_lsbs ||
1694  !ctx->opt_order || !ctx->store_prev_samples ||
1695  !ctx->use_ltp || !ctx->ltp_lag ||
1696  !ctx->ltp_gain || !ctx->ltp_gain_buffer) {
1697  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1698  decode_end(avctx);
1699  return AVERROR(ENOMEM);
1700  }
1701 
1702  for (c = 0; c < num_buffers; c++)
1703  ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;
1704 
1705  // allocate and assign channel data buffer for mcc mode
1706  if (sconf->mc_coding) {
1707  ctx->chan_data_buffer = av_malloc(sizeof(*ctx->chan_data_buffer) *
1708  num_buffers * num_buffers);
1709  ctx->chan_data = av_malloc(sizeof(*ctx->chan_data) *
1710  num_buffers);
1711  ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *
1712  num_buffers);
1713 
1714  if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {
1715  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1716  decode_end(avctx);
1717  return AVERROR(ENOMEM);
1718  }
1719 
1720  for (c = 0; c < num_buffers; c++)
1721  ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;
1722  } else {
1723  ctx->chan_data = NULL;
1724  ctx->chan_data_buffer = NULL;
1725  ctx->reverted_channels = NULL;
1726  }
1727 
1728  channel_size = sconf->frame_length + sconf->max_order;
1729 
1730  ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);
1731  ctx->raw_buffer = av_mallocz(sizeof(*ctx-> raw_buffer) * avctx->channels * channel_size);
1732  ctx->raw_samples = av_malloc (sizeof(*ctx-> raw_samples) * avctx->channels);
1733 
1734  // allocate previous raw sample buffer
1735  if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {
1736  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1737  decode_end(avctx);
1738  return AVERROR(ENOMEM);
1739  }
1740 
1741  // assign raw samples buffers
1742  ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;
1743  for (c = 1; c < avctx->channels; c++)
1744  ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;
1745 
1746  // allocate crc buffer
1747  if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&
1748  (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1749  ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *
1750  ctx->cur_frame_length *
1751  avctx->channels *
1752  av_get_bytes_per_sample(avctx->sample_fmt));
1753  if (!ctx->crc_buffer) {
1754  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1755  decode_end(avctx);
1756  return AVERROR(ENOMEM);
1757  }
1758  }
1759 
1760  ff_dsputil_init(&ctx->dsp, avctx);
1761 
1762  avcodec_get_frame_defaults(&ctx->frame);
1763  avctx->coded_frame = &ctx->frame;
1764 
1765  return 0;
1766 }
1767 
1768 
1769 /** Flush (reset) the frame ID after seeking.
1770  */
1771 static av_cold void flush(AVCodecContext *avctx)
1772 {
1773  ALSDecContext *ctx = avctx->priv_data;
1774 
1775  ctx->frame_id = 0;
1776 }
1777 
1778 
1779 AVCodec ff_als_decoder = {
1780  .name = "als",
1781  .type = AVMEDIA_TYPE_AUDIO,
1782  .id = AV_CODEC_ID_MP4ALS,
1783  .priv_data_size = sizeof(ALSDecContext),
1784  .init = decode_init,
1785  .close = decode_end,
1786  .decode = decode_frame,
1787  .flush = flush,
1788  .capabilities = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
1789  .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),
1790 };
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