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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  ALSSpecificConfig sconf;
196  GetBitContext gb;
197  DSPContext dsp;
198  const AVCRC *crc_table;
199  uint32_t crc_org; ///< CRC value of the original input data
200  uint32_t crc; ///< CRC value calculated from decoded data
201  unsigned int cur_frame_length; ///< length of the current frame to decode
202  unsigned int frame_id; ///< the frame ID / number of the current frame
203  unsigned int js_switch; ///< if true, joint-stereo decoding is enforced
204  unsigned int cs_switch; ///< if true, channel rearrangement is done
205  unsigned int num_blocks; ///< number of blocks used in the current frame
206  unsigned int s_max; ///< maximum Rice parameter allowed in entropy coding
207  uint8_t *bgmc_lut; ///< pointer at lookup tables used for BGMC
208  int *bgmc_lut_status; ///< pointer at lookup table status flags used for BGMC
209  int ltp_lag_length; ///< number of bits used for ltp lag value
210  int *const_block; ///< contains const_block flags for all channels
211  unsigned int *shift_lsbs; ///< contains shift_lsbs flags for all channels
212  unsigned int *opt_order; ///< contains opt_order flags for all channels
213  int *store_prev_samples; ///< contains store_prev_samples flags for all channels
214  int *use_ltp; ///< contains use_ltp flags for all channels
215  int *ltp_lag; ///< contains ltp lag values for all channels
216  int **ltp_gain; ///< gain values for ltp 5-tap filter for a channel
217  int *ltp_gain_buffer; ///< contains all gain values for ltp 5-tap filter
218  int32_t **quant_cof; ///< quantized parcor coefficients for a channel
219  int32_t *quant_cof_buffer; ///< contains all quantized parcor coefficients
220  int32_t **lpc_cof; ///< coefficients of the direct form prediction filter for a channel
221  int32_t *lpc_cof_buffer; ///< contains all coefficients of the direct form prediction filter
222  int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer
223  ALSChannelData **chan_data; ///< channel data for multi-channel correlation
224  ALSChannelData *chan_data_buffer; ///< contains channel data for all channels
225  int *reverted_channels; ///< stores a flag for each reverted channel
226  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
227  int32_t **raw_samples; ///< decoded raw samples for each channel
228  int32_t *raw_buffer; ///< contains all decoded raw samples including carryover samples
229  uint8_t *crc_buffer; ///< buffer of byte order corrected samples used for CRC check
230 } ALSDecContext;
231 
232 
233 typedef struct {
234  unsigned int block_length; ///< number of samples within the block
235  unsigned int ra_block; ///< if true, this is a random access block
236  int *const_block; ///< if true, this is a constant value block
237  int js_blocks; ///< true if this block contains a difference signal
238  unsigned int *shift_lsbs; ///< shift of values for this block
239  unsigned int *opt_order; ///< prediction order of this block
240  int *store_prev_samples;///< if true, carryover samples have to be stored
241  int *use_ltp; ///< if true, long-term prediction is used
242  int *ltp_lag; ///< lag value for long-term prediction
243  int *ltp_gain; ///< gain values for ltp 5-tap filter
244  int32_t *quant_cof; ///< quantized parcor coefficients
245  int32_t *lpc_cof; ///< coefficients of the direct form prediction
246  int32_t *raw_samples; ///< decoded raw samples / residuals for this block
247  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
248  int32_t *raw_other; ///< decoded raw samples of the other channel of a channel pair
249 } ALSBlockData;
250 
251 
252 static av_cold void dprint_specific_config(ALSDecContext *ctx)
253 {
254 #ifdef DEBUG
255  AVCodecContext *avctx = ctx->avctx;
256  ALSSpecificConfig *sconf = &ctx->sconf;
257 
258  av_dlog(avctx, "resolution = %i\n", sconf->resolution);
259  av_dlog(avctx, "floating = %i\n", sconf->floating);
260  av_dlog(avctx, "frame_length = %i\n", sconf->frame_length);
261  av_dlog(avctx, "ra_distance = %i\n", sconf->ra_distance);
262  av_dlog(avctx, "ra_flag = %i\n", sconf->ra_flag);
263  av_dlog(avctx, "adapt_order = %i\n", sconf->adapt_order);
264  av_dlog(avctx, "coef_table = %i\n", sconf->coef_table);
265  av_dlog(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);
266  av_dlog(avctx, "max_order = %i\n", sconf->max_order);
267  av_dlog(avctx, "block_switching = %i\n", sconf->block_switching);
268  av_dlog(avctx, "bgmc = %i\n", sconf->bgmc);
269  av_dlog(avctx, "sb_part = %i\n", sconf->sb_part);
270  av_dlog(avctx, "joint_stereo = %i\n", sconf->joint_stereo);
271  av_dlog(avctx, "mc_coding = %i\n", sconf->mc_coding);
272  av_dlog(avctx, "chan_config = %i\n", sconf->chan_config);
273  av_dlog(avctx, "chan_sort = %i\n", sconf->chan_sort);
274  av_dlog(avctx, "RLSLMS = %i\n", sconf->rlslms);
275  av_dlog(avctx, "chan_config_info = %i\n", sconf->chan_config_info);
276 #endif
277 }
278 
279 
280 /** Read an ALSSpecificConfig from a buffer into the output struct.
281  */
282 static av_cold int read_specific_config(ALSDecContext *ctx)
283 {
284  GetBitContext gb;
285  uint64_t ht_size;
286  int i, config_offset;
287  MPEG4AudioConfig m4ac;
288  ALSSpecificConfig *sconf = &ctx->sconf;
289  AVCodecContext *avctx = ctx->avctx;
290  uint32_t als_id, header_size, trailer_size;
291  int ret;
292 
293  if ((ret = init_get_bits8(&gb, avctx->extradata, avctx->extradata_size)) < 0)
294  return ret;
295 
296  config_offset = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata,
297  avctx->extradata_size * 8, 1);
298 
299  if (config_offset < 0)
300  return -1;
301 
302  skip_bits_long(&gb, config_offset);
303 
304  if (get_bits_left(&gb) < (30 << 3))
305  return -1;
306 
307  // read the fixed items
308  als_id = get_bits_long(&gb, 32);
309  avctx->sample_rate = m4ac.sample_rate;
310  skip_bits_long(&gb, 32); // sample rate already known
311  sconf->samples = get_bits_long(&gb, 32);
312  avctx->channels = m4ac.channels;
313  skip_bits(&gb, 16); // number of channels already known
314  skip_bits(&gb, 3); // skip file_type
315  sconf->resolution = get_bits(&gb, 3);
316  sconf->floating = get_bits1(&gb);
317  sconf->msb_first = get_bits1(&gb);
318  sconf->frame_length = get_bits(&gb, 16) + 1;
319  sconf->ra_distance = get_bits(&gb, 8);
320  sconf->ra_flag = get_bits(&gb, 2);
321  sconf->adapt_order = get_bits1(&gb);
322  sconf->coef_table = get_bits(&gb, 2);
323  sconf->long_term_prediction = get_bits1(&gb);
324  sconf->max_order = get_bits(&gb, 10);
325  sconf->block_switching = get_bits(&gb, 2);
326  sconf->bgmc = get_bits1(&gb);
327  sconf->sb_part = get_bits1(&gb);
328  sconf->joint_stereo = get_bits1(&gb);
329  sconf->mc_coding = get_bits1(&gb);
330  sconf->chan_config = get_bits1(&gb);
331  sconf->chan_sort = get_bits1(&gb);
332  sconf->crc_enabled = get_bits1(&gb);
333  sconf->rlslms = get_bits1(&gb);
334  skip_bits(&gb, 5); // skip 5 reserved bits
335  skip_bits1(&gb); // skip aux_data_enabled
336 
337 
338  // check for ALSSpecificConfig struct
339  if (als_id != MKBETAG('A','L','S','\0'))
340  return -1;
341 
342  ctx->cur_frame_length = sconf->frame_length;
343 
344  // read channel config
345  if (sconf->chan_config)
346  sconf->chan_config_info = get_bits(&gb, 16);
347  // TODO: use this to set avctx->channel_layout
348 
349 
350  // read channel sorting
351  if (sconf->chan_sort && avctx->channels > 1) {
352  int chan_pos_bits = av_ceil_log2(avctx->channels);
353  int bits_needed = avctx->channels * chan_pos_bits + 7;
354  if (get_bits_left(&gb) < bits_needed)
355  return -1;
356 
357  if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))
358  return AVERROR(ENOMEM);
359 
360  ctx->cs_switch = 1;
361 
362  for (i = 0; i < avctx->channels; i++) {
363  int idx;
364 
365  idx = get_bits(&gb, chan_pos_bits);
366  if (idx >= avctx->channels) {
367  av_log(avctx, AV_LOG_WARNING, "Invalid channel reordering.\n");
368  ctx->cs_switch = 0;
369  break;
370  }
371  sconf->chan_pos[idx] = i;
372  }
373 
374  align_get_bits(&gb);
375  }
376 
377 
378  // read fixed header and trailer sizes,
379  // if size = 0xFFFFFFFF then there is no data field!
380  if (get_bits_left(&gb) < 64)
381  return -1;
382 
383  header_size = get_bits_long(&gb, 32);
384  trailer_size = get_bits_long(&gb, 32);
385  if (header_size == 0xFFFFFFFF)
386  header_size = 0;
387  if (trailer_size == 0xFFFFFFFF)
388  trailer_size = 0;
389 
390  ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3;
391 
392 
393  // skip the header and trailer data
394  if (get_bits_left(&gb) < ht_size)
395  return -1;
396 
397  if (ht_size > INT32_MAX)
398  return -1;
399 
400  skip_bits_long(&gb, ht_size);
401 
402 
403  // initialize CRC calculation
404  if (sconf->crc_enabled) {
405  if (get_bits_left(&gb) < 32)
406  return -1;
407 
408  if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
409  ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
410  ctx->crc = 0xFFFFFFFF;
411  ctx->crc_org = ~get_bits_long(&gb, 32);
412  } else
413  skip_bits_long(&gb, 32);
414  }
415 
416 
417  // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)
418 
419  dprint_specific_config(ctx);
420 
421  return 0;
422 }
423 
424 
425 /** Check the ALSSpecificConfig for unsupported features.
426  */
427 static int check_specific_config(ALSDecContext *ctx)
428 {
429  ALSSpecificConfig *sconf = &ctx->sconf;
430  int error = 0;
431 
432  // report unsupported feature and set error value
433  #define MISSING_ERR(cond, str, errval) \
434  { \
435  if (cond) { \
436  av_log_missing_feature(ctx->avctx, str, 0); \
437  error = errval; \
438  } \
439  }
440 
441  MISSING_ERR(sconf->floating, "Floating point decoding", AVERROR_PATCHWELCOME);
442  MISSING_ERR(sconf->rlslms, "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME);
443 
444  return error;
445 }
446 
447 
448 /** Parse the bs_info field to extract the block partitioning used in
449  * block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.
450  */
451 static void parse_bs_info(const uint32_t bs_info, unsigned int n,
452  unsigned int div, unsigned int **div_blocks,
453  unsigned int *num_blocks)
454 {
455  if (n < 31 && ((bs_info << n) & 0x40000000)) {
456  // if the level is valid and the investigated bit n is set
457  // then recursively check both children at bits (2n+1) and (2n+2)
458  n *= 2;
459  div += 1;
460  parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);
461  parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);
462  } else {
463  // else the bit is not set or the last level has been reached
464  // (bit implicitly not set)
465  **div_blocks = div;
466  (*div_blocks)++;
467  (*num_blocks)++;
468  }
469 }
470 
471 
472 /** Read and decode a Rice codeword.
473  */
474 static int32_t decode_rice(GetBitContext *gb, unsigned int k)
475 {
476  int max = get_bits_left(gb) - k;
477  int q = get_unary(gb, 0, max);
478  int r = k ? get_bits1(gb) : !(q & 1);
479 
480  if (k > 1) {
481  q <<= (k - 1);
482  q += get_bits_long(gb, k - 1);
483  } else if (!k) {
484  q >>= 1;
485  }
486  return r ? q : ~q;
487 }
488 
489 
490 /** Convert PARCOR coefficient k to direct filter coefficient.
491  */
492 static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)
493 {
494  int i, j;
495 
496  for (i = 0, j = k - 1; i < j; i++, j--) {
497  int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
498  cof[j] += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);
499  cof[i] += tmp1;
500  }
501  if (i == j)
502  cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
503 
504  cof[k] = par[k];
505 }
506 
507 
508 /** Read block switching field if necessary and set actual block sizes.
509  * Also assure that the block sizes of the last frame correspond to the
510  * actual number of samples.
511  */
512 static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
513  uint32_t *bs_info)
514 {
515  ALSSpecificConfig *sconf = &ctx->sconf;
516  GetBitContext *gb = &ctx->gb;
517  unsigned int *ptr_div_blocks = div_blocks;
518  unsigned int b;
519 
520  if (sconf->block_switching) {
521  unsigned int bs_info_len = 1 << (sconf->block_switching + 2);
522  *bs_info = get_bits_long(gb, bs_info_len);
523  *bs_info <<= (32 - bs_info_len);
524  }
525 
526  ctx->num_blocks = 0;
527  parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);
528 
529  // The last frame may have an overdetermined block structure given in
530  // the bitstream. In that case the defined block structure would need
531  // more samples than available to be consistent.
532  // The block structure is actually used but the block sizes are adapted
533  // to fit the actual number of available samples.
534  // Example: 5 samples, 2nd level block sizes: 2 2 2 2.
535  // This results in the actual block sizes: 2 2 1 0.
536  // This is not specified in 14496-3 but actually done by the reference
537  // codec RM22 revision 2.
538  // This appears to happen in case of an odd number of samples in the last
539  // frame which is actually not allowed by the block length switching part
540  // of 14496-3.
541  // The ALS conformance files feature an odd number of samples in the last
542  // frame.
543 
544  for (b = 0; b < ctx->num_blocks; b++)
545  div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];
546 
547  if (ctx->cur_frame_length != ctx->sconf.frame_length) {
548  unsigned int remaining = ctx->cur_frame_length;
549 
550  for (b = 0; b < ctx->num_blocks; b++) {
551  if (remaining <= div_blocks[b]) {
552  div_blocks[b] = remaining;
553  ctx->num_blocks = b + 1;
554  break;
555  }
556 
557  remaining -= div_blocks[b];
558  }
559  }
560 }
561 
562 
563 /** Read the block data for a constant block
564  */
565 static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
566 {
567  ALSSpecificConfig *sconf = &ctx->sconf;
568  AVCodecContext *avctx = ctx->avctx;
569  GetBitContext *gb = &ctx->gb;
570 
571  if (bd->block_length <= 0)
572  return AVERROR_INVALIDDATA;
573 
574  *bd->raw_samples = 0;
575  *bd->const_block = get_bits1(gb); // 1 = constant value, 0 = zero block (silence)
576  bd->js_blocks = get_bits1(gb);
577 
578  // skip 5 reserved bits
579  skip_bits(gb, 5);
580 
581  if (*bd->const_block) {
582  unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;
583  *bd->raw_samples = get_sbits_long(gb, const_val_bits);
584  }
585 
586  // ensure constant block decoding by reusing this field
587  *bd->const_block = 1;
588 
589  return 0;
590 }
591 
592 
593 /** Decode the block data for a constant block
594  */
595 static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
596 {
597  int smp = bd->block_length - 1;
598  int32_t val = *bd->raw_samples;
599  int32_t *dst = bd->raw_samples + 1;
600 
601  // write raw samples into buffer
602  for (; smp; smp--)
603  *dst++ = val;
604 }
605 
606 
607 /** Read the block data for a non-constant block
608  */
609 static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
610 {
611  ALSSpecificConfig *sconf = &ctx->sconf;
612  AVCodecContext *avctx = ctx->avctx;
613  GetBitContext *gb = &ctx->gb;
614  unsigned int k;
615  unsigned int s[8];
616  unsigned int sx[8];
617  unsigned int sub_blocks, log2_sub_blocks, sb_length;
618  unsigned int start = 0;
619  unsigned int opt_order;
620  int sb;
621  int32_t *quant_cof = bd->quant_cof;
622  int32_t *current_res;
623 
624 
625  // ensure variable block decoding by reusing this field
626  *bd->const_block = 0;
627 
628  *bd->opt_order = 1;
629  bd->js_blocks = get_bits1(gb);
630 
631  opt_order = *bd->opt_order;
632 
633  // determine the number of subblocks for entropy decoding
634  if (!sconf->bgmc && !sconf->sb_part) {
635  log2_sub_blocks = 0;
636  } else {
637  if (sconf->bgmc && sconf->sb_part)
638  log2_sub_blocks = get_bits(gb, 2);
639  else
640  log2_sub_blocks = 2 * get_bits1(gb);
641  }
642 
643  sub_blocks = 1 << log2_sub_blocks;
644 
645  // do not continue in case of a damaged stream since
646  // block_length must be evenly divisible by sub_blocks
647  if (bd->block_length & (sub_blocks - 1)) {
648  av_log(avctx, AV_LOG_WARNING,
649  "Block length is not evenly divisible by the number of subblocks.\n");
650  return -1;
651  }
652 
653  sb_length = bd->block_length >> log2_sub_blocks;
654 
655  if (sconf->bgmc) {
656  s[0] = get_bits(gb, 8 + (sconf->resolution > 1));
657  for (k = 1; k < sub_blocks; k++)
658  s[k] = s[k - 1] + decode_rice(gb, 2);
659 
660  for (k = 0; k < sub_blocks; k++) {
661  sx[k] = s[k] & 0x0F;
662  s [k] >>= 4;
663  }
664  } else {
665  s[0] = get_bits(gb, 4 + (sconf->resolution > 1));
666  for (k = 1; k < sub_blocks; k++)
667  s[k] = s[k - 1] + decode_rice(gb, 0);
668  }
669  for (k = 1; k < sub_blocks; k++)
670  if (s[k] > 32) {
671  av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");
672  return AVERROR_INVALIDDATA;
673  }
674 
675  if (get_bits1(gb))
676  *bd->shift_lsbs = get_bits(gb, 4) + 1;
677 
678  *bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || *bd->shift_lsbs;
679 
680 
681  if (!sconf->rlslms) {
682  if (sconf->adapt_order) {
683  int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,
684  2, sconf->max_order + 1));
685  *bd->opt_order = get_bits(gb, opt_order_length);
686  if (*bd->opt_order > sconf->max_order) {
687  *bd->opt_order = sconf->max_order;
688  av_log(avctx, AV_LOG_ERROR, "Predictor order too large.\n");
689  return AVERROR_INVALIDDATA;
690  }
691  } else {
692  *bd->opt_order = sconf->max_order;
693  }
694 
695  opt_order = *bd->opt_order;
696 
697  if (opt_order) {
698  int add_base;
699 
700  if (sconf->coef_table == 3) {
701  add_base = 0x7F;
702 
703  // read coefficient 0
704  quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];
705 
706  // read coefficient 1
707  if (opt_order > 1)
708  quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];
709 
710  // read coefficients 2 to opt_order
711  for (k = 2; k < opt_order; k++)
712  quant_cof[k] = get_bits(gb, 7);
713  } else {
714  int k_max;
715  add_base = 1;
716 
717  // read coefficient 0 to 19
718  k_max = FFMIN(opt_order, 20);
719  for (k = 0; k < k_max; k++) {
720  int rice_param = parcor_rice_table[sconf->coef_table][k][1];
721  int offset = parcor_rice_table[sconf->coef_table][k][0];
722  quant_cof[k] = decode_rice(gb, rice_param) + offset;
723  if (quant_cof[k] < -64 || quant_cof[k] > 63) {
724  av_log(avctx, AV_LOG_ERROR, "quant_cof %d is out of range.\n", quant_cof[k]);
725  return AVERROR_INVALIDDATA;
726  }
727  }
728 
729  // read coefficients 20 to 126
730  k_max = FFMIN(opt_order, 127);
731  for (; k < k_max; k++)
732  quant_cof[k] = decode_rice(gb, 2) + (k & 1);
733 
734  // read coefficients 127 to opt_order
735  for (; k < opt_order; k++)
736  quant_cof[k] = decode_rice(gb, 1);
737 
738  quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];
739 
740  if (opt_order > 1)
741  quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];
742  }
743 
744  for (k = 2; k < opt_order; k++)
745  quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);
746  }
747  }
748 
749  // read LTP gain and lag values
750  if (sconf->long_term_prediction) {
751  *bd->use_ltp = get_bits1(gb);
752 
753  if (*bd->use_ltp) {
754  int r, c;
755 
756  bd->ltp_gain[0] = decode_rice(gb, 1) << 3;
757  bd->ltp_gain[1] = decode_rice(gb, 2) << 3;
758 
759  r = get_unary(gb, 0, 3);
760  c = get_bits(gb, 2);
761  bd->ltp_gain[2] = ltp_gain_values[r][c];
762 
763  bd->ltp_gain[3] = decode_rice(gb, 2) << 3;
764  bd->ltp_gain[4] = decode_rice(gb, 1) << 3;
765 
766  *bd->ltp_lag = get_bits(gb, ctx->ltp_lag_length);
767  *bd->ltp_lag += FFMAX(4, opt_order + 1);
768  }
769  }
770 
771  // read first value and residuals in case of a random access block
772  if (bd->ra_block) {
773  if (opt_order)
774  bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
775  if (opt_order > 1)
776  bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));
777  if (opt_order > 2)
778  bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));
779 
780  start = FFMIN(opt_order, 3);
781  }
782 
783  // read all residuals
784  if (sconf->bgmc) {
785  int delta[8];
786  unsigned int k [8];
787  unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5);
788 
789  // read most significant bits
790  unsigned int high;
791  unsigned int low;
792  unsigned int value;
793 
794  ff_bgmc_decode_init(gb, &high, &low, &value);
795 
796  current_res = bd->raw_samples + start;
797 
798  for (sb = 0; sb < sub_blocks; sb++) {
799  unsigned int sb_len = sb_length - (sb ? 0 : start);
800 
801  k [sb] = s[sb] > b ? s[sb] - b : 0;
802  delta[sb] = 5 - s[sb] + k[sb];
803 
804  ff_bgmc_decode(gb, sb_len, current_res,
805  delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);
806 
807  current_res += sb_len;
808  }
809 
810  ff_bgmc_decode_end(gb);
811 
812 
813  // read least significant bits and tails
814  current_res = bd->raw_samples + start;
815 
816  for (sb = 0; sb < sub_blocks; sb++, start = 0) {
817  unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]];
818  unsigned int cur_k = k[sb];
819  unsigned int cur_s = s[sb];
820 
821  for (; start < sb_length; start++) {
822  int32_t res = *current_res;
823 
824  if (res == cur_tail_code) {
825  unsigned int max_msb = (2 + (sx[sb] > 2) + (sx[sb] > 10))
826  << (5 - delta[sb]);
827 
828  res = decode_rice(gb, cur_s);
829 
830  if (res >= 0) {
831  res += (max_msb ) << cur_k;
832  } else {
833  res -= (max_msb - 1) << cur_k;
834  }
835  } else {
836  if (res > cur_tail_code)
837  res--;
838 
839  if (res & 1)
840  res = -res;
841 
842  res >>= 1;
843 
844  if (cur_k) {
845  res <<= cur_k;
846  res |= get_bits_long(gb, cur_k);
847  }
848  }
849 
850  *current_res++ = res;
851  }
852  }
853  } else {
854  current_res = bd->raw_samples + start;
855 
856  for (sb = 0; sb < sub_blocks; sb++, start = 0)
857  for (; start < sb_length; start++)
858  *current_res++ = decode_rice(gb, s[sb]);
859  }
860 
861  if (!sconf->mc_coding || ctx->js_switch)
862  align_get_bits(gb);
863 
864  return 0;
865 }
866 
867 
868 /** Decode the block data for a non-constant block
869  */
870 static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
871 {
872  ALSSpecificConfig *sconf = &ctx->sconf;
873  unsigned int block_length = bd->block_length;
874  unsigned int smp = 0;
875  unsigned int k;
876  int opt_order = *bd->opt_order;
877  int sb;
878  int64_t y;
879  int32_t *quant_cof = bd->quant_cof;
880  int32_t *lpc_cof = bd->lpc_cof;
881  int32_t *raw_samples = bd->raw_samples;
882  int32_t *raw_samples_end = bd->raw_samples + bd->block_length;
883  int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;
884 
885  // reverse long-term prediction
886  if (*bd->use_ltp) {
887  int ltp_smp;
888 
889  for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {
890  int center = ltp_smp - *bd->ltp_lag;
891  int begin = FFMAX(0, center - 2);
892  int end = center + 3;
893  int tab = 5 - (end - begin);
894  int base;
895 
896  y = 1 << 6;
897 
898  for (base = begin; base < end; base++, tab++)
899  y += MUL64(bd->ltp_gain[tab], raw_samples[base]);
900 
901  raw_samples[ltp_smp] += y >> 7;
902  }
903  }
904 
905  // reconstruct all samples from residuals
906  if (bd->ra_block) {
907  for (smp = 0; smp < opt_order; smp++) {
908  y = 1 << 19;
909 
910  for (sb = 0; sb < smp; sb++)
911  y += MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);
912 
913  *raw_samples++ -= y >> 20;
914  parcor_to_lpc(smp, quant_cof, lpc_cof);
915  }
916  } else {
917  for (k = 0; k < opt_order; k++)
918  parcor_to_lpc(k, quant_cof, lpc_cof);
919 
920  // store previous samples in case that they have to be altered
921  if (*bd->store_prev_samples)
922  memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,
923  sizeof(*bd->prev_raw_samples) * sconf->max_order);
924 
925  // reconstruct difference signal for prediction (joint-stereo)
926  if (bd->js_blocks && bd->raw_other) {
927  int32_t *left, *right;
928 
929  if (bd->raw_other > raw_samples) { // D = R - L
930  left = raw_samples;
931  right = bd->raw_other;
932  } else { // D = R - L
933  left = bd->raw_other;
934  right = raw_samples;
935  }
936 
937  for (sb = -1; sb >= -sconf->max_order; sb--)
938  raw_samples[sb] = right[sb] - left[sb];
939  }
940 
941  // reconstruct shifted signal
942  if (*bd->shift_lsbs)
943  for (sb = -1; sb >= -sconf->max_order; sb--)
944  raw_samples[sb] >>= *bd->shift_lsbs;
945  }
946 
947  // reverse linear prediction coefficients for efficiency
948  lpc_cof = lpc_cof + opt_order;
949 
950  for (sb = 0; sb < opt_order; sb++)
951  lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];
952 
953  // reconstruct raw samples
954  raw_samples = bd->raw_samples + smp;
955  lpc_cof = lpc_cof_reversed + opt_order;
956 
957  for (; raw_samples < raw_samples_end; raw_samples++) {
958  y = 1 << 19;
959 
960  for (sb = -opt_order; sb < 0; sb++)
961  y += MUL64(lpc_cof[sb], raw_samples[sb]);
962 
963  *raw_samples -= y >> 20;
964  }
965 
966  raw_samples = bd->raw_samples;
967 
968  // restore previous samples in case that they have been altered
969  if (*bd->store_prev_samples)
970  memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,
971  sizeof(*raw_samples) * sconf->max_order);
972 
973  return 0;
974 }
975 
976 
977 /** Read the block data.
978  */
979 static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
980 {
981  GetBitContext *gb = &ctx->gb;
982  int ret;
983 
984  *bd->shift_lsbs = 0;
985  // read block type flag and read the samples accordingly
986  if (get_bits1(gb)) {
987  if ((ret = read_var_block_data(ctx, bd)) < 0)
988  return ret;
989  } else {
990  if ((ret = read_const_block_data(ctx, bd)) < 0)
991  return ret;
992  }
993 
994  return 0;
995 }
996 
997 
998 /** Decode the block data.
999  */
1000 static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1001 {
1002  unsigned int smp;
1003 
1004  // read block type flag and read the samples accordingly
1005  if (*bd->const_block)
1006  decode_const_block_data(ctx, bd);
1007  else if (decode_var_block_data(ctx, bd))
1008  return -1;
1009 
1010  // TODO: read RLSLMS extension data
1011 
1012  if (*bd->shift_lsbs)
1013  for (smp = 0; smp < bd->block_length; smp++)
1014  bd->raw_samples[smp] <<= *bd->shift_lsbs;
1015 
1016  return 0;
1017 }
1018 
1019 
1020 /** Read and decode block data successively.
1021  */
1022 static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1023 {
1024  int ret;
1025 
1026  ret = read_block(ctx, bd);
1027 
1028  if (ret)
1029  return ret;
1030 
1031  ret = decode_block(ctx, bd);
1032 
1033  return ret;
1034 }
1035 
1036 
1037 /** Compute the number of samples left to decode for the current frame and
1038  * sets these samples to zero.
1039  */
1040 static void zero_remaining(unsigned int b, unsigned int b_max,
1041  const unsigned int *div_blocks, int32_t *buf)
1042 {
1043  unsigned int count = 0;
1044 
1045  while (b < b_max)
1046  count += div_blocks[b++];
1047 
1048  if (count)
1049  memset(buf, 0, sizeof(*buf) * count);
1050 }
1051 
1052 
1053 /** Decode blocks independently.
1054  */
1055 static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,
1056  unsigned int c, const unsigned int *div_blocks,
1057  unsigned int *js_blocks)
1058 {
1059  unsigned int b;
1060  ALSBlockData bd = { 0 };
1061 
1062  bd.ra_block = ra_frame;
1063  bd.const_block = ctx->const_block;
1064  bd.shift_lsbs = ctx->shift_lsbs;
1065  bd.opt_order = ctx->opt_order;
1066  bd.store_prev_samples = ctx->store_prev_samples;
1067  bd.use_ltp = ctx->use_ltp;
1068  bd.ltp_lag = ctx->ltp_lag;
1069  bd.ltp_gain = ctx->ltp_gain[0];
1070  bd.quant_cof = ctx->quant_cof[0];
1071  bd.lpc_cof = ctx->lpc_cof[0];
1072  bd.prev_raw_samples = ctx->prev_raw_samples;
1073  bd.raw_samples = ctx->raw_samples[c];
1074 
1075 
1076  for (b = 0; b < ctx->num_blocks; b++) {
1077  bd.block_length = div_blocks[b];
1078 
1079  if (read_decode_block(ctx, &bd)) {
1080  // damaged block, write zero for the rest of the frame
1081  zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);
1082  return -1;
1083  }
1084  bd.raw_samples += div_blocks[b];
1085  bd.ra_block = 0;
1086  }
1087 
1088  return 0;
1089 }
1090 
1091 
1092 /** Decode blocks dependently.
1093  */
1094 static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
1095  unsigned int c, const unsigned int *div_blocks,
1096  unsigned int *js_blocks)
1097 {
1098  ALSSpecificConfig *sconf = &ctx->sconf;
1099  unsigned int offset = 0;
1100  unsigned int b;
1101  ALSBlockData bd[2] = { { 0 } };
1102 
1103  bd[0].ra_block = ra_frame;
1104  bd[0].const_block = ctx->const_block;
1105  bd[0].shift_lsbs = ctx->shift_lsbs;
1106  bd[0].opt_order = ctx->opt_order;
1107  bd[0].store_prev_samples = ctx->store_prev_samples;
1108  bd[0].use_ltp = ctx->use_ltp;
1109  bd[0].ltp_lag = ctx->ltp_lag;
1110  bd[0].ltp_gain = ctx->ltp_gain[0];
1111  bd[0].quant_cof = ctx->quant_cof[0];
1112  bd[0].lpc_cof = ctx->lpc_cof[0];
1113  bd[0].prev_raw_samples = ctx->prev_raw_samples;
1114  bd[0].js_blocks = *js_blocks;
1115 
1116  bd[1].ra_block = ra_frame;
1117  bd[1].const_block = ctx->const_block;
1118  bd[1].shift_lsbs = ctx->shift_lsbs;
1119  bd[1].opt_order = ctx->opt_order;
1120  bd[1].store_prev_samples = ctx->store_prev_samples;
1121  bd[1].use_ltp = ctx->use_ltp;
1122  bd[1].ltp_lag = ctx->ltp_lag;
1123  bd[1].ltp_gain = ctx->ltp_gain[0];
1124  bd[1].quant_cof = ctx->quant_cof[0];
1125  bd[1].lpc_cof = ctx->lpc_cof[0];
1126  bd[1].prev_raw_samples = ctx->prev_raw_samples;
1127  bd[1].js_blocks = *(js_blocks + 1);
1128 
1129  // decode all blocks
1130  for (b = 0; b < ctx->num_blocks; b++) {
1131  unsigned int s;
1132 
1133  bd[0].block_length = div_blocks[b];
1134  bd[1].block_length = div_blocks[b];
1135 
1136  bd[0].raw_samples = ctx->raw_samples[c ] + offset;
1137  bd[1].raw_samples = ctx->raw_samples[c + 1] + offset;
1138 
1139  bd[0].raw_other = bd[1].raw_samples;
1140  bd[1].raw_other = bd[0].raw_samples;
1141 
1142  if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {
1143  // damaged block, write zero for the rest of the frame
1144  zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);
1145  zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);
1146  return -1;
1147  }
1148 
1149  // reconstruct joint-stereo blocks
1150  if (bd[0].js_blocks) {
1151  if (bd[1].js_blocks)
1152  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");
1153 
1154  for (s = 0; s < div_blocks[b]; s++)
1155  bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];
1156  } else if (bd[1].js_blocks) {
1157  for (s = 0; s < div_blocks[b]; s++)
1158  bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];
1159  }
1160 
1161  offset += div_blocks[b];
1162  bd[0].ra_block = 0;
1163  bd[1].ra_block = 0;
1164  }
1165 
1166  // store carryover raw samples,
1167  // the others channel raw samples are stored by the calling function.
1168  memmove(ctx->raw_samples[c] - sconf->max_order,
1169  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1170  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1171 
1172  return 0;
1173 }
1174 
1175 
1176 /** Read the channel data.
1177  */
1178 static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)
1179 {
1180  GetBitContext *gb = &ctx->gb;
1181  ALSChannelData *current = cd;
1182  unsigned int channels = ctx->avctx->channels;
1183  int entries = 0;
1184 
1185  while (entries < channels && !(current->stop_flag = get_bits1(gb))) {
1186  current->master_channel = get_bits_long(gb, av_ceil_log2(channels));
1187 
1188  if (current->master_channel >= channels) {
1189  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n");
1190  return -1;
1191  }
1192 
1193  if (current->master_channel != c) {
1194  current->time_diff_flag = get_bits1(gb);
1195  current->weighting[0] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1196  current->weighting[1] = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 31)];
1197  current->weighting[2] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1198 
1199  if (current->time_diff_flag) {
1200  current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1201  current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1202  current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1203 
1204  current->time_diff_sign = get_bits1(gb);
1205  current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;
1206  }
1207  }
1208 
1209  current++;
1210  entries++;
1211  }
1212 
1213  if (entries == channels) {
1214  av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data.\n");
1215  return -1;
1216  }
1217 
1218  align_get_bits(gb);
1219  return 0;
1220 }
1221 
1222 
1223 /** Recursively reverts the inter-channel correlation for a block.
1224  */
1225 static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,
1226  ALSChannelData **cd, int *reverted,
1227  unsigned int offset, int c)
1228 {
1229  ALSChannelData *ch = cd[c];
1230  unsigned int dep = 0;
1231  unsigned int channels = ctx->avctx->channels;
1232 
1233  if (reverted[c])
1234  return 0;
1235 
1236  reverted[c] = 1;
1237 
1238  while (dep < channels && !ch[dep].stop_flag) {
1239  revert_channel_correlation(ctx, bd, cd, reverted, offset,
1240  ch[dep].master_channel);
1241 
1242  dep++;
1243  }
1244 
1245  if (dep == channels) {
1246  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n");
1247  return -1;
1248  }
1249 
1250  bd->const_block = ctx->const_block + c;
1251  bd->shift_lsbs = ctx->shift_lsbs + c;
1252  bd->opt_order = ctx->opt_order + c;
1253  bd->store_prev_samples = ctx->store_prev_samples + c;
1254  bd->use_ltp = ctx->use_ltp + c;
1255  bd->ltp_lag = ctx->ltp_lag + c;
1256  bd->ltp_gain = ctx->ltp_gain[c];
1257  bd->lpc_cof = ctx->lpc_cof[c];
1258  bd->quant_cof = ctx->quant_cof[c];
1259  bd->raw_samples = ctx->raw_samples[c] + offset;
1260 
1261  dep = 0;
1262  while (!ch[dep].stop_flag) {
1263  unsigned int smp;
1264  unsigned int begin = 1;
1265  unsigned int end = bd->block_length - 1;
1266  int64_t y;
1267  int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;
1268 
1269  if (ch[dep].time_diff_flag) {
1270  int t = ch[dep].time_diff_index;
1271 
1272  if (ch[dep].time_diff_sign) {
1273  t = -t;
1274  begin -= t;
1275  } else {
1276  end -= t;
1277  }
1278 
1279  for (smp = begin; smp < end; smp++) {
1280  y = (1 << 6) +
1281  MUL64(ch[dep].weighting[0], master[smp - 1 ]) +
1282  MUL64(ch[dep].weighting[1], master[smp ]) +
1283  MUL64(ch[dep].weighting[2], master[smp + 1 ]) +
1284  MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +
1285  MUL64(ch[dep].weighting[4], master[smp + t]) +
1286  MUL64(ch[dep].weighting[5], master[smp + 1 + t]);
1287 
1288  bd->raw_samples[smp] += y >> 7;
1289  }
1290  } else {
1291  for (smp = begin; smp < end; smp++) {
1292  y = (1 << 6) +
1293  MUL64(ch[dep].weighting[0], master[smp - 1]) +
1294  MUL64(ch[dep].weighting[1], master[smp ]) +
1295  MUL64(ch[dep].weighting[2], master[smp + 1]);
1296 
1297  bd->raw_samples[smp] += y >> 7;
1298  }
1299  }
1300 
1301  dep++;
1302  }
1303 
1304  return 0;
1305 }
1306 
1307 
1308 /** Read the frame data.
1309  */
1310 static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
1311 {
1312  ALSSpecificConfig *sconf = &ctx->sconf;
1313  AVCodecContext *avctx = ctx->avctx;
1314  GetBitContext *gb = &ctx->gb;
1315  unsigned int div_blocks[32]; ///< block sizes.
1316  unsigned int c;
1317  unsigned int js_blocks[2];
1318 
1319  uint32_t bs_info = 0;
1320 
1321  // skip the size of the ra unit if present in the frame
1322  if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)
1323  skip_bits_long(gb, 32);
1324 
1325  if (sconf->mc_coding && sconf->joint_stereo) {
1326  ctx->js_switch = get_bits1(gb);
1327  align_get_bits(gb);
1328  }
1329 
1330  if (!sconf->mc_coding || ctx->js_switch) {
1331  int independent_bs = !sconf->joint_stereo;
1332 
1333  for (c = 0; c < avctx->channels; c++) {
1334  js_blocks[0] = 0;
1335  js_blocks[1] = 0;
1336 
1337  get_block_sizes(ctx, div_blocks, &bs_info);
1338 
1339  // if joint_stereo and block_switching is set, independent decoding
1340  // is signaled via the first bit of bs_info
1341  if (sconf->joint_stereo && sconf->block_switching)
1342  if (bs_info >> 31)
1343  independent_bs = 2;
1344 
1345  // if this is the last channel, it has to be decoded independently
1346  if (c == avctx->channels - 1)
1347  independent_bs = 1;
1348 
1349  if (independent_bs) {
1350  if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))
1351  return -1;
1352 
1353  independent_bs--;
1354  } else {
1355  if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))
1356  return -1;
1357 
1358  c++;
1359  }
1360 
1361  // store carryover raw samples
1362  memmove(ctx->raw_samples[c] - sconf->max_order,
1363  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1364  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1365  }
1366  } else { // multi-channel coding
1367  ALSBlockData bd = { 0 };
1368  int b, ret;
1369  int *reverted_channels = ctx->reverted_channels;
1370  unsigned int offset = 0;
1371 
1372  for (c = 0; c < avctx->channels; c++)
1373  if (ctx->chan_data[c] < ctx->chan_data_buffer) {
1374  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n");
1375  return -1;
1376  }
1377 
1378  memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);
1379 
1380  bd.ra_block = ra_frame;
1381  bd.prev_raw_samples = ctx->prev_raw_samples;
1382 
1383  get_block_sizes(ctx, div_blocks, &bs_info);
1384 
1385  for (b = 0; b < ctx->num_blocks; b++) {
1386  bd.block_length = div_blocks[b];
1387 
1388  for (c = 0; c < avctx->channels; c++) {
1389  bd.const_block = ctx->const_block + c;
1390  bd.shift_lsbs = ctx->shift_lsbs + c;
1391  bd.opt_order = ctx->opt_order + c;
1392  bd.store_prev_samples = ctx->store_prev_samples + c;
1393  bd.use_ltp = ctx->use_ltp + c;
1394  bd.ltp_lag = ctx->ltp_lag + c;
1395  bd.ltp_gain = ctx->ltp_gain[c];
1396  bd.lpc_cof = ctx->lpc_cof[c];
1397  bd.quant_cof = ctx->quant_cof[c];
1398  bd.raw_samples = ctx->raw_samples[c] + offset;
1399  bd.raw_other = NULL;
1400 
1401  if ((ret = read_block(ctx, &bd)) < 0)
1402  return ret;
1403  if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)
1404  return ret;
1405  }
1406 
1407  for (c = 0; c < avctx->channels; c++)
1408  if (revert_channel_correlation(ctx, &bd, ctx->chan_data,
1409  reverted_channels, offset, c))
1410  return -1;
1411 
1412  for (c = 0; c < avctx->channels; c++) {
1413  bd.const_block = ctx->const_block + c;
1414  bd.shift_lsbs = ctx->shift_lsbs + c;
1415  bd.opt_order = ctx->opt_order + c;
1416  bd.store_prev_samples = ctx->store_prev_samples + c;
1417  bd.use_ltp = ctx->use_ltp + c;
1418  bd.ltp_lag = ctx->ltp_lag + c;
1419  bd.ltp_gain = ctx->ltp_gain[c];
1420  bd.lpc_cof = ctx->lpc_cof[c];
1421  bd.quant_cof = ctx->quant_cof[c];
1422  bd.raw_samples = ctx->raw_samples[c] + offset;
1423 
1424  if ((ret = decode_block(ctx, &bd)) < 0)
1425  return ret;
1426  }
1427 
1428  memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));
1429  offset += div_blocks[b];
1430  bd.ra_block = 0;
1431  }
1432 
1433  // store carryover raw samples
1434  for (c = 0; c < avctx->channels; c++)
1435  memmove(ctx->raw_samples[c] - sconf->max_order,
1436  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1437  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1438  }
1439 
1440  // TODO: read_diff_float_data
1441 
1442  return 0;
1443 }
1444 
1445 
1446 /** Decode an ALS frame.
1447  */
1448 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
1449  AVPacket *avpkt)
1450 {
1451  ALSDecContext *ctx = avctx->priv_data;
1452  AVFrame *frame = data;
1453  ALSSpecificConfig *sconf = &ctx->sconf;
1454  const uint8_t *buffer = avpkt->data;
1455  int buffer_size = avpkt->size;
1456  int invalid_frame, ret;
1457  unsigned int c, sample, ra_frame, bytes_read, shift;
1458 
1459  init_get_bits(&ctx->gb, buffer, buffer_size * 8);
1460 
1461  // In the case that the distance between random access frames is set to zero
1462  // (sconf->ra_distance == 0) no frame is treated as a random access frame.
1463  // For the first frame, if prediction is used, all samples used from the
1464  // previous frame are assumed to be zero.
1465  ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);
1466 
1467  // the last frame to decode might have a different length
1468  if (sconf->samples != 0xFFFFFFFF)
1469  ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,
1470  sconf->frame_length);
1471  else
1472  ctx->cur_frame_length = sconf->frame_length;
1473 
1474  // decode the frame data
1475  if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)
1476  av_log(ctx->avctx, AV_LOG_WARNING,
1477  "Reading frame data failed. Skipping RA unit.\n");
1478 
1479  ctx->frame_id++;
1480 
1481  /* get output buffer */
1482  frame->nb_samples = ctx->cur_frame_length;
1483  if ((ret = ff_get_buffer(avctx, frame)) < 0) {
1484  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
1485  return ret;
1486  }
1487 
1488  // transform decoded frame into output format
1489  #define INTERLEAVE_OUTPUT(bps) \
1490  { \
1491  int##bps##_t *dest = (int##bps##_t*)frame->data[0]; \
1492  shift = bps - ctx->avctx->bits_per_raw_sample; \
1493  if (!ctx->cs_switch) { \
1494  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1495  for (c = 0; c < avctx->channels; c++) \
1496  *dest++ = ctx->raw_samples[c][sample] << shift; \
1497  } else { \
1498  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1499  for (c = 0; c < avctx->channels; c++) \
1500  *dest++ = ctx->raw_samples[sconf->chan_pos[c]][sample] << shift; \
1501  } \
1502  }
1503 
1504  if (ctx->avctx->bits_per_raw_sample <= 16) {
1505  INTERLEAVE_OUTPUT(16)
1506  } else {
1507  INTERLEAVE_OUTPUT(32)
1508  }
1509 
1510  // update CRC
1511  if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1512  int swap = HAVE_BIGENDIAN != sconf->msb_first;
1513 
1514  if (ctx->avctx->bits_per_raw_sample == 24) {
1515  int32_t *src = (int32_t *)frame->data[0];
1516 
1517  for (sample = 0;
1518  sample < ctx->cur_frame_length * avctx->channels;
1519  sample++) {
1520  int32_t v;
1521 
1522  if (swap)
1523  v = av_bswap32(src[sample]);
1524  else
1525  v = src[sample];
1526  if (!HAVE_BIGENDIAN)
1527  v >>= 8;
1528 
1529  ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);
1530  }
1531  } else {
1532  uint8_t *crc_source;
1533 
1534  if (swap) {
1535  if (ctx->avctx->bits_per_raw_sample <= 16) {
1536  int16_t *src = (int16_t*) frame->data[0];
1537  int16_t *dest = (int16_t*) ctx->crc_buffer;
1538  for (sample = 0;
1539  sample < ctx->cur_frame_length * avctx->channels;
1540  sample++)
1541  *dest++ = av_bswap16(src[sample]);
1542  } else {
1543  ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,
1544  (uint32_t *)frame->data[0],
1545  ctx->cur_frame_length * avctx->channels);
1546  }
1547  crc_source = ctx->crc_buffer;
1548  } else {
1549  crc_source = frame->data[0];
1550  }
1551 
1552  ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,
1553  ctx->cur_frame_length * avctx->channels *
1554  av_get_bytes_per_sample(avctx->sample_fmt));
1555  }
1556 
1557 
1558  // check CRC sums if this is the last frame
1559  if (ctx->cur_frame_length != sconf->frame_length &&
1560  ctx->crc_org != ctx->crc) {
1561  av_log(avctx, AV_LOG_ERROR, "CRC error.\n");
1562  }
1563  }
1564 
1565  *got_frame_ptr = 1;
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  return 0;
1763 }
1764 
1765 
1766 /** Flush (reset) the frame ID after seeking.
1767  */
1768 static av_cold void flush(AVCodecContext *avctx)
1769 {
1770  ALSDecContext *ctx = avctx->priv_data;
1771 
1772  ctx->frame_id = 0;
1773 }
1774 
1775 
1776 AVCodec ff_als_decoder = {
1777  .name = "als",
1778  .type = AVMEDIA_TYPE_AUDIO,
1779  .id = AV_CODEC_ID_MP4ALS,
1780  .priv_data_size = sizeof(ALSDecContext),
1781  .init = decode_init,
1782  .close = decode_end,
1783  .decode = decode_frame,
1784  .flush = flush,
1785  .capabilities = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
1786  .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),
1787 };
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