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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 #include "avcodec.h"
29 #include "get_bits.h"
30 #include "unary.h"
31 #include "mpeg4audio.h"
32 #include "bytestream.h"
33 #include "bgmc.h"
34 #include "dsputil.h"
35 #include "internal.h"
36 #include "libavutil/samplefmt.h"
37 #include "libavutil/crc.h"
38 
39 #include <stdint.h>
40 
41 /** Rice parameters and corresponding index offsets for decoding the
42  * indices of scaled PARCOR values. The table chosen is set globally
43  * by the encoder and stored in ALSSpecificConfig.
44  */
45 static const int8_t parcor_rice_table[3][20][2] = {
46  { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},
47  { 12, 3}, { -7, 3}, { 9, 3}, { -5, 3}, { 6, 3},
48  { -4, 3}, { 3, 3}, { -3, 2}, { 3, 2}, { -2, 2},
49  { 3, 2}, { -1, 2}, { 2, 2}, { -1, 2}, { 2, 2} },
50  { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},
51  { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},
52  {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},
53  { 7, 3}, { -4, 4}, { 3, 3}, { -1, 3}, { 1, 3} },
54  { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},
55  { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},
56  {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},
57  { 3, 3}, { 0, 3}, { -1, 3}, { 2, 3}, { -1, 2} }
58 };
59 
60 
61 /** Scaled PARCOR values used for the first two PARCOR coefficients.
62  * To be indexed by the Rice coded indices.
63  * Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20)
64  * Actual values are divided by 32 in order to be stored in 16 bits.
65  */
66 static const int16_t parcor_scaled_values[] = {
67  -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,
68  -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,
69  -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,
70  -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,
71  -1013728 / 32, -1009376 / 32, -1004768 / 32, -999904 / 32,
72  -994784 / 32, -989408 / 32, -983776 / 32, -977888 / 32,
73  -971744 / 32, -965344 / 32, -958688 / 32, -951776 / 32,
74  -944608 / 32, -937184 / 32, -929504 / 32, -921568 / 32,
75  -913376 / 32, -904928 / 32, -896224 / 32, -887264 / 32,
76  -878048 / 32, -868576 / 32, -858848 / 32, -848864 / 32,
77  -838624 / 32, -828128 / 32, -817376 / 32, -806368 / 32,
78  -795104 / 32, -783584 / 32, -771808 / 32, -759776 / 32,
79  -747488 / 32, -734944 / 32, -722144 / 32, -709088 / 32,
80  -695776 / 32, -682208 / 32, -668384 / 32, -654304 / 32,
81  -639968 / 32, -625376 / 32, -610528 / 32, -595424 / 32,
82  -580064 / 32, -564448 / 32, -548576 / 32, -532448 / 32,
83  -516064 / 32, -499424 / 32, -482528 / 32, -465376 / 32,
84  -447968 / 32, -430304 / 32, -412384 / 32, -394208 / 32,
85  -375776 / 32, -357088 / 32, -338144 / 32, -318944 / 32,
86  -299488 / 32, -279776 / 32, -259808 / 32, -239584 / 32,
87  -219104 / 32, -198368 / 32, -177376 / 32, -156128 / 32,
88  -134624 / 32, -112864 / 32, -90848 / 32, -68576 / 32,
89  -46048 / 32, -23264 / 32, -224 / 32, 23072 / 32,
90  46624 / 32, 70432 / 32, 94496 / 32, 118816 / 32,
91  143392 / 32, 168224 / 32, 193312 / 32, 218656 / 32,
92  244256 / 32, 270112 / 32, 296224 / 32, 322592 / 32,
93  349216 / 32, 376096 / 32, 403232 / 32, 430624 / 32,
94  458272 / 32, 486176 / 32, 514336 / 32, 542752 / 32,
95  571424 / 32, 600352 / 32, 629536 / 32, 658976 / 32,
96  688672 / 32, 718624 / 32, 748832 / 32, 779296 / 32,
97  810016 / 32, 840992 / 32, 872224 / 32, 903712 / 32,
98  935456 / 32, 967456 / 32, 999712 / 32, 1032224 / 32
99 };
100 
101 
102 /** Gain values of p(0) for long-term prediction.
103  * To be indexed by the Rice coded indices.
104  */
105 static const uint8_t ltp_gain_values [4][4] = {
106  { 0, 8, 16, 24},
107  {32, 40, 48, 56},
108  {64, 70, 76, 82},
109  {88, 92, 96, 100}
110 };
111 
112 
113 /** Inter-channel weighting factors for multi-channel correlation.
114  * To be indexed by the Rice coded indices.
115  */
116 static const int16_t mcc_weightings[] = {
117  204, 192, 179, 166, 153, 140, 128, 115,
118  102, 89, 76, 64, 51, 38, 25, 12,
119  0, -12, -25, -38, -51, -64, -76, -89,
120  -102, -115, -128, -140, -153, -166, -179, -192
121 };
122 
123 
124 /** Tail codes used in arithmetic coding using block Gilbert-Moore codes.
125  */
126 static const uint8_t tail_code[16][6] = {
127  { 74, 44, 25, 13, 7, 3},
128  { 68, 42, 24, 13, 7, 3},
129  { 58, 39, 23, 13, 7, 3},
130  {126, 70, 37, 19, 10, 5},
131  {132, 70, 37, 20, 10, 5},
132  {124, 70, 38, 20, 10, 5},
133  {120, 69, 37, 20, 11, 5},
134  {116, 67, 37, 20, 11, 5},
135  {108, 66, 36, 20, 10, 5},
136  {102, 62, 36, 20, 10, 5},
137  { 88, 58, 34, 19, 10, 5},
138  {162, 89, 49, 25, 13, 7},
139  {156, 87, 49, 26, 14, 7},
140  {150, 86, 47, 26, 14, 7},
141  {142, 84, 47, 26, 14, 7},
142  {131, 79, 46, 26, 14, 7}
143 };
144 
145 
146 enum RA_Flag {
147  RA_FLAG_NONE,
148  RA_FLAG_FRAMES,
149  RA_FLAG_HEADER
150 };
151 
152 
153 typedef struct {
154  uint32_t samples; ///< number of samples, 0xFFFFFFFF if unknown
155  int resolution; ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit
156  int floating; ///< 1 = IEEE 32-bit floating-point, 0 = integer
157  int msb_first; ///< 1 = original CRC calculated on big-endian system, 0 = little-endian
158  int frame_length; ///< frame length for each frame (last frame may differ)
159  int ra_distance; ///< distance between RA frames (in frames, 0...255)
160  enum RA_Flag ra_flag; ///< indicates where the size of ra units is stored
161  int adapt_order; ///< adaptive order: 1 = on, 0 = off
162  int coef_table; ///< table index of Rice code parameters
163  int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off
164  int max_order; ///< maximum prediction order (0..1023)
165  int block_switching; ///< number of block switching levels
166  int bgmc; ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)
167  int sb_part; ///< sub-block partition
168  int joint_stereo; ///< joint stereo: 1 = on, 0 = off
169  int mc_coding; ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off
170  int chan_config; ///< indicates that a chan_config_info field is present
171  int chan_sort; ///< channel rearrangement: 1 = on, 0 = off
172  int rlslms; ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off
173  int chan_config_info; ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.
174  int *chan_pos; ///< original channel positions
175  int crc_enabled; ///< enable Cyclic Redundancy Checksum
176 } ALSSpecificConfig;
177 
178 
179 typedef struct {
180  int stop_flag;
181  int master_channel;
182  int time_diff_flag;
183  int time_diff_sign;
184  int time_diff_index;
185  int weighting[6];
186 } ALSChannelData;
187 
188 
189 typedef struct {
190  AVCodecContext *avctx;
191  ALSSpecificConfig sconf;
192  GetBitContext gb;
193  DSPContext dsp;
194  const AVCRC *crc_table;
195  uint32_t crc_org; ///< CRC value of the original input data
196  uint32_t crc; ///< CRC value calculated from decoded data
197  unsigned int cur_frame_length; ///< length of the current frame to decode
198  unsigned int frame_id; ///< the frame ID / number of the current frame
199  unsigned int js_switch; ///< if true, joint-stereo decoding is enforced
200  unsigned int cs_switch; ///< if true, channel rearrangement is done
201  unsigned int num_blocks; ///< number of blocks used in the current frame
202  unsigned int s_max; ///< maximum Rice parameter allowed in entropy coding
203  uint8_t *bgmc_lut; ///< pointer at lookup tables used for BGMC
204  int *bgmc_lut_status; ///< pointer at lookup table status flags used for BGMC
205  int ltp_lag_length; ///< number of bits used for ltp lag value
206  int *const_block; ///< contains const_block flags for all channels
207  unsigned int *shift_lsbs; ///< contains shift_lsbs flags for all channels
208  unsigned int *opt_order; ///< contains opt_order flags for all channels
209  int *store_prev_samples; ///< contains store_prev_samples flags for all channels
210  int *use_ltp; ///< contains use_ltp flags for all channels
211  int *ltp_lag; ///< contains ltp lag values for all channels
212  int **ltp_gain; ///< gain values for ltp 5-tap filter for a channel
213  int *ltp_gain_buffer; ///< contains all gain values for ltp 5-tap filter
214  int32_t **quant_cof; ///< quantized parcor coefficients for a channel
215  int32_t *quant_cof_buffer; ///< contains all quantized parcor coefficients
216  int32_t **lpc_cof; ///< coefficients of the direct form prediction filter for a channel
217  int32_t *lpc_cof_buffer; ///< contains all coefficients of the direct form prediction filter
218  int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer
219  ALSChannelData **chan_data; ///< channel data for multi-channel correlation
220  ALSChannelData *chan_data_buffer; ///< contains channel data for all channels
221  int *reverted_channels; ///< stores a flag for each reverted channel
222  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
223  int32_t **raw_samples; ///< decoded raw samples for each channel
224  int32_t *raw_buffer; ///< contains all decoded raw samples including carryover samples
225  uint8_t *crc_buffer; ///< buffer of byte order corrected samples used for CRC check
226 } ALSDecContext;
227 
228 
229 typedef struct {
230  unsigned int block_length; ///< number of samples within the block
231  unsigned int ra_block; ///< if true, this is a random access block
232  int *const_block; ///< if true, this is a constant value block
233  int js_blocks; ///< true if this block contains a difference signal
234  unsigned int *shift_lsbs; ///< shift of values for this block
235  unsigned int *opt_order; ///< prediction order of this block
236  int *store_prev_samples;///< if true, carryover samples have to be stored
237  int *use_ltp; ///< if true, long-term prediction is used
238  int *ltp_lag; ///< lag value for long-term prediction
239  int *ltp_gain; ///< gain values for ltp 5-tap filter
240  int32_t *quant_cof; ///< quantized parcor coefficients
241  int32_t *lpc_cof; ///< coefficients of the direct form prediction
242  int32_t *raw_samples; ///< decoded raw samples / residuals for this block
243  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
244  int32_t *raw_other; ///< decoded raw samples of the other channel of a channel pair
245 } ALSBlockData;
246 
247 
248 static av_cold void dprint_specific_config(ALSDecContext *ctx)
249 {
250 #ifdef DEBUG
251  AVCodecContext *avctx = ctx->avctx;
252  ALSSpecificConfig *sconf = &ctx->sconf;
253 
254  av_dlog(avctx, "resolution = %i\n", sconf->resolution);
255  av_dlog(avctx, "floating = %i\n", sconf->floating);
256  av_dlog(avctx, "frame_length = %i\n", sconf->frame_length);
257  av_dlog(avctx, "ra_distance = %i\n", sconf->ra_distance);
258  av_dlog(avctx, "ra_flag = %i\n", sconf->ra_flag);
259  av_dlog(avctx, "adapt_order = %i\n", sconf->adapt_order);
260  av_dlog(avctx, "coef_table = %i\n", sconf->coef_table);
261  av_dlog(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);
262  av_dlog(avctx, "max_order = %i\n", sconf->max_order);
263  av_dlog(avctx, "block_switching = %i\n", sconf->block_switching);
264  av_dlog(avctx, "bgmc = %i\n", sconf->bgmc);
265  av_dlog(avctx, "sb_part = %i\n", sconf->sb_part);
266  av_dlog(avctx, "joint_stereo = %i\n", sconf->joint_stereo);
267  av_dlog(avctx, "mc_coding = %i\n", sconf->mc_coding);
268  av_dlog(avctx, "chan_config = %i\n", sconf->chan_config);
269  av_dlog(avctx, "chan_sort = %i\n", sconf->chan_sort);
270  av_dlog(avctx, "RLSLMS = %i\n", sconf->rlslms);
271  av_dlog(avctx, "chan_config_info = %i\n", sconf->chan_config_info);
272 #endif
273 }
274 
275 
276 /** Read an ALSSpecificConfig from a buffer into the output struct.
277  */
278 static av_cold int read_specific_config(ALSDecContext *ctx)
279 {
280  GetBitContext gb;
281  uint64_t ht_size;
282  int i, config_offset;
283  MPEG4AudioConfig m4ac;
284  ALSSpecificConfig *sconf = &ctx->sconf;
285  AVCodecContext *avctx = ctx->avctx;
286  uint32_t als_id, header_size, trailer_size;
287  int ret;
288 
289  if ((ret = init_get_bits8(&gb, avctx->extradata, avctx->extradata_size)) < 0)
290  return ret;
291 
292  config_offset = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata,
293  avctx->extradata_size * 8, 1);
294 
295  if (config_offset < 0)
296  return -1;
297 
298  skip_bits_long(&gb, config_offset);
299 
300  if (get_bits_left(&gb) < (30 << 3))
301  return -1;
302 
303  // read the fixed items
304  als_id = get_bits_long(&gb, 32);
305  avctx->sample_rate = m4ac.sample_rate;
306  skip_bits_long(&gb, 32); // sample rate already known
307  sconf->samples = get_bits_long(&gb, 32);
308  avctx->channels = m4ac.channels;
309  skip_bits(&gb, 16); // number of channels already known
310  skip_bits(&gb, 3); // skip file_type
311  sconf->resolution = get_bits(&gb, 3);
312  sconf->floating = get_bits1(&gb);
313  sconf->msb_first = get_bits1(&gb);
314  sconf->frame_length = get_bits(&gb, 16) + 1;
315  sconf->ra_distance = get_bits(&gb, 8);
316  sconf->ra_flag = get_bits(&gb, 2);
317  sconf->adapt_order = get_bits1(&gb);
318  sconf->coef_table = get_bits(&gb, 2);
319  sconf->long_term_prediction = get_bits1(&gb);
320  sconf->max_order = get_bits(&gb, 10);
321  sconf->block_switching = get_bits(&gb, 2);
322  sconf->bgmc = get_bits1(&gb);
323  sconf->sb_part = get_bits1(&gb);
324  sconf->joint_stereo = get_bits1(&gb);
325  sconf->mc_coding = get_bits1(&gb);
326  sconf->chan_config = get_bits1(&gb);
327  sconf->chan_sort = get_bits1(&gb);
328  sconf->crc_enabled = get_bits1(&gb);
329  sconf->rlslms = get_bits1(&gb);
330  skip_bits(&gb, 5); // skip 5 reserved bits
331  skip_bits1(&gb); // skip aux_data_enabled
332 
333 
334  // check for ALSSpecificConfig struct
335  if (als_id != MKBETAG('A','L','S','\0'))
336  return -1;
337 
338  ctx->cur_frame_length = sconf->frame_length;
339 
340  // read channel config
341  if (sconf->chan_config)
342  sconf->chan_config_info = get_bits(&gb, 16);
343  // TODO: use this to set avctx->channel_layout
344 
345 
346  // read channel sorting
347  if (sconf->chan_sort && avctx->channels > 1) {
348  int chan_pos_bits = av_ceil_log2(avctx->channels);
349  int bits_needed = avctx->channels * chan_pos_bits + 7;
350  if (get_bits_left(&gb) < bits_needed)
351  return -1;
352 
353  if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))
354  return AVERROR(ENOMEM);
355 
356  ctx->cs_switch = 1;
357 
358  for (i = 0; i < avctx->channels; i++) {
359  int idx;
360 
361  idx = get_bits(&gb, chan_pos_bits);
362  if (idx >= avctx->channels) {
363  av_log(avctx, AV_LOG_WARNING, "Invalid channel reordering.\n");
364  ctx->cs_switch = 0;
365  break;
366  }
367  sconf->chan_pos[idx] = i;
368  }
369 
370  align_get_bits(&gb);
371  }
372 
373 
374  // read fixed header and trailer sizes,
375  // if size = 0xFFFFFFFF then there is no data field!
376  if (get_bits_left(&gb) < 64)
377  return -1;
378 
379  header_size = get_bits_long(&gb, 32);
380  trailer_size = get_bits_long(&gb, 32);
381  if (header_size == 0xFFFFFFFF)
382  header_size = 0;
383  if (trailer_size == 0xFFFFFFFF)
384  trailer_size = 0;
385 
386  ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3;
387 
388 
389  // skip the header and trailer data
390  if (get_bits_left(&gb) < ht_size)
391  return -1;
392 
393  if (ht_size > INT32_MAX)
394  return -1;
395 
396  skip_bits_long(&gb, ht_size);
397 
398 
399  // initialize CRC calculation
400  if (sconf->crc_enabled) {
401  if (get_bits_left(&gb) < 32)
402  return -1;
403 
404  if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
405  ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
406  ctx->crc = 0xFFFFFFFF;
407  ctx->crc_org = ~get_bits_long(&gb, 32);
408  } else
409  skip_bits_long(&gb, 32);
410  }
411 
412 
413  // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)
414 
415  dprint_specific_config(ctx);
416 
417  return 0;
418 }
419 
420 
421 /** Check the ALSSpecificConfig for unsupported features.
422  */
423 static int check_specific_config(ALSDecContext *ctx)
424 {
425  ALSSpecificConfig *sconf = &ctx->sconf;
426  int error = 0;
427 
428  // report unsupported feature and set error value
429  #define MISSING_ERR(cond, str, errval) \
430  { \
431  if (cond) { \
432  avpriv_report_missing_feature(ctx->avctx, \
433  str); \
434  error = errval; \
435  } \
436  }
437 
438  MISSING_ERR(sconf->floating, "Floating point decoding", AVERROR_PATCHWELCOME);
439  MISSING_ERR(sconf->rlslms, "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME);
440 
441  return error;
442 }
443 
444 
445 /** Parse the bs_info field to extract the block partitioning used in
446  * block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.
447  */
448 static void parse_bs_info(const uint32_t bs_info, unsigned int n,
449  unsigned int div, unsigned int **div_blocks,
450  unsigned int *num_blocks)
451 {
452  if (n < 31 && ((bs_info << n) & 0x40000000)) {
453  // if the level is valid and the investigated bit n is set
454  // then recursively check both children at bits (2n+1) and (2n+2)
455  n *= 2;
456  div += 1;
457  parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);
458  parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);
459  } else {
460  // else the bit is not set or the last level has been reached
461  // (bit implicitly not set)
462  **div_blocks = div;
463  (*div_blocks)++;
464  (*num_blocks)++;
465  }
466 }
467 
468 
469 /** Read and decode a Rice codeword.
470  */
471 static int32_t decode_rice(GetBitContext *gb, unsigned int k)
472 {
473  int max = get_bits_left(gb) - k;
474  int q = get_unary(gb, 0, max);
475  int r = k ? get_bits1(gb) : !(q & 1);
476 
477  if (k > 1) {
478  q <<= (k - 1);
479  q += get_bits_long(gb, k - 1);
480  } else if (!k) {
481  q >>= 1;
482  }
483  return r ? q : ~q;
484 }
485 
486 
487 /** Convert PARCOR coefficient k to direct filter coefficient.
488  */
489 static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)
490 {
491  int i, j;
492 
493  for (i = 0, j = k - 1; i < j; i++, j--) {
494  int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
495  cof[j] += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);
496  cof[i] += tmp1;
497  }
498  if (i == j)
499  cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
500 
501  cof[k] = par[k];
502 }
503 
504 
505 /** Read block switching field if necessary and set actual block sizes.
506  * Also assure that the block sizes of the last frame correspond to the
507  * actual number of samples.
508  */
509 static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
510  uint32_t *bs_info)
511 {
512  ALSSpecificConfig *sconf = &ctx->sconf;
513  GetBitContext *gb = &ctx->gb;
514  unsigned int *ptr_div_blocks = div_blocks;
515  unsigned int b;
516 
517  if (sconf->block_switching) {
518  unsigned int bs_info_len = 1 << (sconf->block_switching + 2);
519  *bs_info = get_bits_long(gb, bs_info_len);
520  *bs_info <<= (32 - bs_info_len);
521  }
522 
523  ctx->num_blocks = 0;
524  parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);
525 
526  // The last frame may have an overdetermined block structure given in
527  // the bitstream. In that case the defined block structure would need
528  // more samples than available to be consistent.
529  // The block structure is actually used but the block sizes are adapted
530  // to fit the actual number of available samples.
531  // Example: 5 samples, 2nd level block sizes: 2 2 2 2.
532  // This results in the actual block sizes: 2 2 1 0.
533  // This is not specified in 14496-3 but actually done by the reference
534  // codec RM22 revision 2.
535  // This appears to happen in case of an odd number of samples in the last
536  // frame which is actually not allowed by the block length switching part
537  // of 14496-3.
538  // The ALS conformance files feature an odd number of samples in the last
539  // frame.
540 
541  for (b = 0; b < ctx->num_blocks; b++)
542  div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];
543 
544  if (ctx->cur_frame_length != ctx->sconf.frame_length) {
545  unsigned int remaining = ctx->cur_frame_length;
546 
547  for (b = 0; b < ctx->num_blocks; b++) {
548  if (remaining <= div_blocks[b]) {
549  div_blocks[b] = remaining;
550  ctx->num_blocks = b + 1;
551  break;
552  }
553 
554  remaining -= div_blocks[b];
555  }
556  }
557 }
558 
559 
560 /** Read the block data for a constant block
561  */
562 static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
563 {
564  ALSSpecificConfig *sconf = &ctx->sconf;
565  AVCodecContext *avctx = ctx->avctx;
566  GetBitContext *gb = &ctx->gb;
567 
568  if (bd->block_length <= 0)
569  return AVERROR_INVALIDDATA;
570 
571  *bd->raw_samples = 0;
572  *bd->const_block = get_bits1(gb); // 1 = constant value, 0 = zero block (silence)
573  bd->js_blocks = get_bits1(gb);
574 
575  // skip 5 reserved bits
576  skip_bits(gb, 5);
577 
578  if (*bd->const_block) {
579  unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;
580  *bd->raw_samples = get_sbits_long(gb, const_val_bits);
581  }
582 
583  // ensure constant block decoding by reusing this field
584  *bd->const_block = 1;
585 
586  return 0;
587 }
588 
589 
590 /** Decode the block data for a constant block
591  */
592 static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
593 {
594  int smp = bd->block_length - 1;
595  int32_t val = *bd->raw_samples;
596  int32_t *dst = bd->raw_samples + 1;
597 
598  // write raw samples into buffer
599  for (; smp; smp--)
600  *dst++ = val;
601 }
602 
603 
604 /** Read the block data for a non-constant block
605  */
606 static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
607 {
608  ALSSpecificConfig *sconf = &ctx->sconf;
609  AVCodecContext *avctx = ctx->avctx;
610  GetBitContext *gb = &ctx->gb;
611  unsigned int k;
612  unsigned int s[8];
613  unsigned int sx[8];
614  unsigned int sub_blocks, log2_sub_blocks, sb_length;
615  unsigned int start = 0;
616  unsigned int opt_order;
617  int sb;
618  int32_t *quant_cof = bd->quant_cof;
619  int32_t *current_res;
620 
621 
622  // ensure variable block decoding by reusing this field
623  *bd->const_block = 0;
624 
625  *bd->opt_order = 1;
626  bd->js_blocks = get_bits1(gb);
627 
628  opt_order = *bd->opt_order;
629 
630  // determine the number of subblocks for entropy decoding
631  if (!sconf->bgmc && !sconf->sb_part) {
632  log2_sub_blocks = 0;
633  } else {
634  if (sconf->bgmc && sconf->sb_part)
635  log2_sub_blocks = get_bits(gb, 2);
636  else
637  log2_sub_blocks = 2 * get_bits1(gb);
638  }
639 
640  sub_blocks = 1 << log2_sub_blocks;
641 
642  // do not continue in case of a damaged stream since
643  // block_length must be evenly divisible by sub_blocks
644  if (bd->block_length & (sub_blocks - 1)) {
645  av_log(avctx, AV_LOG_WARNING,
646  "Block length is not evenly divisible by the number of subblocks.\n");
647  return -1;
648  }
649 
650  sb_length = bd->block_length >> log2_sub_blocks;
651 
652  if (sconf->bgmc) {
653  s[0] = get_bits(gb, 8 + (sconf->resolution > 1));
654  for (k = 1; k < sub_blocks; k++)
655  s[k] = s[k - 1] + decode_rice(gb, 2);
656 
657  for (k = 0; k < sub_blocks; k++) {
658  sx[k] = s[k] & 0x0F;
659  s [k] >>= 4;
660  }
661  } else {
662  s[0] = get_bits(gb, 4 + (sconf->resolution > 1));
663  for (k = 1; k < sub_blocks; k++)
664  s[k] = s[k - 1] + decode_rice(gb, 0);
665  }
666  for (k = 1; k < sub_blocks; k++)
667  if (s[k] > 32) {
668  av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");
669  return AVERROR_INVALIDDATA;
670  }
671 
672  if (get_bits1(gb))
673  *bd->shift_lsbs = get_bits(gb, 4) + 1;
674 
675  *bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || *bd->shift_lsbs;
676 
677 
678  if (!sconf->rlslms) {
679  if (sconf->adapt_order) {
680  int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,
681  2, sconf->max_order + 1));
682  *bd->opt_order = get_bits(gb, opt_order_length);
683  if (*bd->opt_order > sconf->max_order) {
684  *bd->opt_order = sconf->max_order;
685  av_log(avctx, AV_LOG_ERROR, "Predictor order too large.\n");
686  return AVERROR_INVALIDDATA;
687  }
688  } else {
689  *bd->opt_order = sconf->max_order;
690  }
691 
692  opt_order = *bd->opt_order;
693 
694  if (opt_order) {
695  int add_base;
696 
697  if (sconf->coef_table == 3) {
698  add_base = 0x7F;
699 
700  // read coefficient 0
701  quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];
702 
703  // read coefficient 1
704  if (opt_order > 1)
705  quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];
706 
707  // read coefficients 2 to opt_order
708  for (k = 2; k < opt_order; k++)
709  quant_cof[k] = get_bits(gb, 7);
710  } else {
711  int k_max;
712  add_base = 1;
713 
714  // read coefficient 0 to 19
715  k_max = FFMIN(opt_order, 20);
716  for (k = 0; k < k_max; k++) {
717  int rice_param = parcor_rice_table[sconf->coef_table][k][1];
718  int offset = parcor_rice_table[sconf->coef_table][k][0];
719  quant_cof[k] = decode_rice(gb, rice_param) + offset;
720  if (quant_cof[k] < -64 || quant_cof[k] > 63) {
721  av_log(avctx, AV_LOG_ERROR, "quant_cof %d is out of range.\n", quant_cof[k]);
722  return AVERROR_INVALIDDATA;
723  }
724  }
725 
726  // read coefficients 20 to 126
727  k_max = FFMIN(opt_order, 127);
728  for (; k < k_max; k++)
729  quant_cof[k] = decode_rice(gb, 2) + (k & 1);
730 
731  // read coefficients 127 to opt_order
732  for (; k < opt_order; k++)
733  quant_cof[k] = decode_rice(gb, 1);
734 
735  quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];
736 
737  if (opt_order > 1)
738  quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];
739  }
740 
741  for (k = 2; k < opt_order; k++)
742  quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);
743  }
744  }
745 
746  // read LTP gain and lag values
747  if (sconf->long_term_prediction) {
748  *bd->use_ltp = get_bits1(gb);
749 
750  if (*bd->use_ltp) {
751  int r, c;
752 
753  bd->ltp_gain[0] = decode_rice(gb, 1) << 3;
754  bd->ltp_gain[1] = decode_rice(gb, 2) << 3;
755 
756  r = get_unary(gb, 0, 3);
757  c = get_bits(gb, 2);
758  bd->ltp_gain[2] = ltp_gain_values[r][c];
759 
760  bd->ltp_gain[3] = decode_rice(gb, 2) << 3;
761  bd->ltp_gain[4] = decode_rice(gb, 1) << 3;
762 
763  *bd->ltp_lag = get_bits(gb, ctx->ltp_lag_length);
764  *bd->ltp_lag += FFMAX(4, opt_order + 1);
765  }
766  }
767 
768  // read first value and residuals in case of a random access block
769  if (bd->ra_block) {
770  if (opt_order)
771  bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
772  if (opt_order > 1)
773  bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));
774  if (opt_order > 2)
775  bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));
776 
777  start = FFMIN(opt_order, 3);
778  }
779 
780  // read all residuals
781  if (sconf->bgmc) {
782  int delta[8];
783  unsigned int k [8];
784  unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5);
785 
786  // read most significant bits
787  unsigned int high;
788  unsigned int low;
789  unsigned int value;
790 
791  ff_bgmc_decode_init(gb, &high, &low, &value);
792 
793  current_res = bd->raw_samples + start;
794 
795  for (sb = 0; sb < sub_blocks; sb++) {
796  unsigned int sb_len = sb_length - (sb ? 0 : start);
797 
798  k [sb] = s[sb] > b ? s[sb] - b : 0;
799  delta[sb] = 5 - s[sb] + k[sb];
800 
801  ff_bgmc_decode(gb, sb_len, current_res,
802  delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);
803 
804  current_res += sb_len;
805  }
806 
807  ff_bgmc_decode_end(gb);
808 
809 
810  // read least significant bits and tails
811  current_res = bd->raw_samples + start;
812 
813  for (sb = 0; sb < sub_blocks; sb++, start = 0) {
814  unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]];
815  unsigned int cur_k = k[sb];
816  unsigned int cur_s = s[sb];
817 
818  for (; start < sb_length; start++) {
819  int32_t res = *current_res;
820 
821  if (res == cur_tail_code) {
822  unsigned int max_msb = (2 + (sx[sb] > 2) + (sx[sb] > 10))
823  << (5 - delta[sb]);
824 
825  res = decode_rice(gb, cur_s);
826 
827  if (res >= 0) {
828  res += (max_msb ) << cur_k;
829  } else {
830  res -= (max_msb - 1) << cur_k;
831  }
832  } else {
833  if (res > cur_tail_code)
834  res--;
835 
836  if (res & 1)
837  res = -res;
838 
839  res >>= 1;
840 
841  if (cur_k) {
842  res <<= cur_k;
843  res |= get_bits_long(gb, cur_k);
844  }
845  }
846 
847  *current_res++ = res;
848  }
849  }
850  } else {
851  current_res = bd->raw_samples + start;
852 
853  for (sb = 0; sb < sub_blocks; sb++, start = 0)
854  for (; start < sb_length; start++)
855  *current_res++ = decode_rice(gb, s[sb]);
856  }
857 
858  if (!sconf->mc_coding || ctx->js_switch)
859  align_get_bits(gb);
860 
861  return 0;
862 }
863 
864 
865 /** Decode the block data for a non-constant block
866  */
867 static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
868 {
869  ALSSpecificConfig *sconf = &ctx->sconf;
870  unsigned int block_length = bd->block_length;
871  unsigned int smp = 0;
872  unsigned int k;
873  int opt_order = *bd->opt_order;
874  int sb;
875  int64_t y;
876  int32_t *quant_cof = bd->quant_cof;
877  int32_t *lpc_cof = bd->lpc_cof;
878  int32_t *raw_samples = bd->raw_samples;
879  int32_t *raw_samples_end = bd->raw_samples + bd->block_length;
880  int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;
881 
882  // reverse long-term prediction
883  if (*bd->use_ltp) {
884  int ltp_smp;
885 
886  for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {
887  int center = ltp_smp - *bd->ltp_lag;
888  int begin = FFMAX(0, center - 2);
889  int end = center + 3;
890  int tab = 5 - (end - begin);
891  int base;
892 
893  y = 1 << 6;
894 
895  for (base = begin; base < end; base++, tab++)
896  y += MUL64(bd->ltp_gain[tab], raw_samples[base]);
897 
898  raw_samples[ltp_smp] += y >> 7;
899  }
900  }
901 
902  // reconstruct all samples from residuals
903  if (bd->ra_block) {
904  for (smp = 0; smp < opt_order; smp++) {
905  y = 1 << 19;
906 
907  for (sb = 0; sb < smp; sb++)
908  y += MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);
909 
910  *raw_samples++ -= y >> 20;
911  parcor_to_lpc(smp, quant_cof, lpc_cof);
912  }
913  } else {
914  for (k = 0; k < opt_order; k++)
915  parcor_to_lpc(k, quant_cof, lpc_cof);
916 
917  // store previous samples in case that they have to be altered
918  if (*bd->store_prev_samples)
919  memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,
920  sizeof(*bd->prev_raw_samples) * sconf->max_order);
921 
922  // reconstruct difference signal for prediction (joint-stereo)
923  if (bd->js_blocks && bd->raw_other) {
924  int32_t *left, *right;
925 
926  if (bd->raw_other > raw_samples) { // D = R - L
927  left = raw_samples;
928  right = bd->raw_other;
929  } else { // D = R - L
930  left = bd->raw_other;
931  right = raw_samples;
932  }
933 
934  for (sb = -1; sb >= -sconf->max_order; sb--)
935  raw_samples[sb] = right[sb] - left[sb];
936  }
937 
938  // reconstruct shifted signal
939  if (*bd->shift_lsbs)
940  for (sb = -1; sb >= -sconf->max_order; sb--)
941  raw_samples[sb] >>= *bd->shift_lsbs;
942  }
943 
944  // reverse linear prediction coefficients for efficiency
945  lpc_cof = lpc_cof + opt_order;
946 
947  for (sb = 0; sb < opt_order; sb++)
948  lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];
949 
950  // reconstruct raw samples
951  raw_samples = bd->raw_samples + smp;
952  lpc_cof = lpc_cof_reversed + opt_order;
953 
954  for (; raw_samples < raw_samples_end; raw_samples++) {
955  y = 1 << 19;
956 
957  for (sb = -opt_order; sb < 0; sb++)
958  y += MUL64(lpc_cof[sb], raw_samples[sb]);
959 
960  *raw_samples -= y >> 20;
961  }
962 
963  raw_samples = bd->raw_samples;
964 
965  // restore previous samples in case that they have been altered
966  if (*bd->store_prev_samples)
967  memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,
968  sizeof(*raw_samples) * sconf->max_order);
969 
970  return 0;
971 }
972 
973 
974 /** Read the block data.
975  */
976 static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
977 {
978  GetBitContext *gb = &ctx->gb;
979  int ret;
980 
981  *bd->shift_lsbs = 0;
982  // read block type flag and read the samples accordingly
983  if (get_bits1(gb)) {
984  if ((ret = read_var_block_data(ctx, bd)) < 0)
985  return ret;
986  } else {
987  if ((ret = read_const_block_data(ctx, bd)) < 0)
988  return ret;
989  }
990 
991  return 0;
992 }
993 
994 
995 /** Decode the block data.
996  */
997 static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)
998 {
999  unsigned int smp;
1000 
1001  // read block type flag and read the samples accordingly
1002  if (*bd->const_block)
1003  decode_const_block_data(ctx, bd);
1004  else if (decode_var_block_data(ctx, bd))
1005  return -1;
1006 
1007  // TODO: read RLSLMS extension data
1008 
1009  if (*bd->shift_lsbs)
1010  for (smp = 0; smp < bd->block_length; smp++)
1011  bd->raw_samples[smp] <<= *bd->shift_lsbs;
1012 
1013  return 0;
1014 }
1015 
1016 
1017 /** Read and decode block data successively.
1018  */
1019 static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1020 {
1021  int ret;
1022 
1023  ret = read_block(ctx, bd);
1024 
1025  if (ret)
1026  return ret;
1027 
1028  ret = decode_block(ctx, bd);
1029 
1030  return ret;
1031 }
1032 
1033 
1034 /** Compute the number of samples left to decode for the current frame and
1035  * sets these samples to zero.
1036  */
1037 static void zero_remaining(unsigned int b, unsigned int b_max,
1038  const unsigned int *div_blocks, int32_t *buf)
1039 {
1040  unsigned int count = 0;
1041 
1042  while (b < b_max)
1043  count += div_blocks[b++];
1044 
1045  if (count)
1046  memset(buf, 0, sizeof(*buf) * count);
1047 }
1048 
1049 
1050 /** Decode blocks independently.
1051  */
1052 static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,
1053  unsigned int c, const unsigned int *div_blocks,
1054  unsigned int *js_blocks)
1055 {
1056  unsigned int b;
1057  ALSBlockData bd = { 0 };
1058 
1059  bd.ra_block = ra_frame;
1060  bd.const_block = ctx->const_block;
1061  bd.shift_lsbs = ctx->shift_lsbs;
1062  bd.opt_order = ctx->opt_order;
1063  bd.store_prev_samples = ctx->store_prev_samples;
1064  bd.use_ltp = ctx->use_ltp;
1065  bd.ltp_lag = ctx->ltp_lag;
1066  bd.ltp_gain = ctx->ltp_gain[0];
1067  bd.quant_cof = ctx->quant_cof[0];
1068  bd.lpc_cof = ctx->lpc_cof[0];
1069  bd.prev_raw_samples = ctx->prev_raw_samples;
1070  bd.raw_samples = ctx->raw_samples[c];
1071 
1072 
1073  for (b = 0; b < ctx->num_blocks; b++) {
1074  bd.block_length = div_blocks[b];
1075 
1076  if (read_decode_block(ctx, &bd)) {
1077  // damaged block, write zero for the rest of the frame
1078  zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);
1079  return -1;
1080  }
1081  bd.raw_samples += div_blocks[b];
1082  bd.ra_block = 0;
1083  }
1084 
1085  return 0;
1086 }
1087 
1088 
1089 /** Decode blocks dependently.
1090  */
1091 static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
1092  unsigned int c, const unsigned int *div_blocks,
1093  unsigned int *js_blocks)
1094 {
1095  ALSSpecificConfig *sconf = &ctx->sconf;
1096  unsigned int offset = 0;
1097  unsigned int b;
1098  ALSBlockData bd[2] = { { 0 } };
1099 
1100  bd[0].ra_block = ra_frame;
1101  bd[0].const_block = ctx->const_block;
1102  bd[0].shift_lsbs = ctx->shift_lsbs;
1103  bd[0].opt_order = ctx->opt_order;
1104  bd[0].store_prev_samples = ctx->store_prev_samples;
1105  bd[0].use_ltp = ctx->use_ltp;
1106  bd[0].ltp_lag = ctx->ltp_lag;
1107  bd[0].ltp_gain = ctx->ltp_gain[0];
1108  bd[0].quant_cof = ctx->quant_cof[0];
1109  bd[0].lpc_cof = ctx->lpc_cof[0];
1110  bd[0].prev_raw_samples = ctx->prev_raw_samples;
1111  bd[0].js_blocks = *js_blocks;
1112 
1113  bd[1].ra_block = ra_frame;
1114  bd[1].const_block = ctx->const_block;
1115  bd[1].shift_lsbs = ctx->shift_lsbs;
1116  bd[1].opt_order = ctx->opt_order;
1117  bd[1].store_prev_samples = ctx->store_prev_samples;
1118  bd[1].use_ltp = ctx->use_ltp;
1119  bd[1].ltp_lag = ctx->ltp_lag;
1120  bd[1].ltp_gain = ctx->ltp_gain[0];
1121  bd[1].quant_cof = ctx->quant_cof[0];
1122  bd[1].lpc_cof = ctx->lpc_cof[0];
1123  bd[1].prev_raw_samples = ctx->prev_raw_samples;
1124  bd[1].js_blocks = *(js_blocks + 1);
1125 
1126  // decode all blocks
1127  for (b = 0; b < ctx->num_blocks; b++) {
1128  unsigned int s;
1129 
1130  bd[0].block_length = div_blocks[b];
1131  bd[1].block_length = div_blocks[b];
1132 
1133  bd[0].raw_samples = ctx->raw_samples[c ] + offset;
1134  bd[1].raw_samples = ctx->raw_samples[c + 1] + offset;
1135 
1136  bd[0].raw_other = bd[1].raw_samples;
1137  bd[1].raw_other = bd[0].raw_samples;
1138 
1139  if(read_decode_block(ctx, &bd[0]) || read_decode_block(ctx, &bd[1])) {
1140  // damaged block, write zero for the rest of the frame
1141  zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);
1142  zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);
1143  return -1;
1144  }
1145 
1146  // reconstruct joint-stereo blocks
1147  if (bd[0].js_blocks) {
1148  if (bd[1].js_blocks)
1149  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");
1150 
1151  for (s = 0; s < div_blocks[b]; s++)
1152  bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];
1153  } else if (bd[1].js_blocks) {
1154  for (s = 0; s < div_blocks[b]; s++)
1155  bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];
1156  }
1157 
1158  offset += div_blocks[b];
1159  bd[0].ra_block = 0;
1160  bd[1].ra_block = 0;
1161  }
1162 
1163  // store carryover raw samples,
1164  // the others channel raw samples are stored by the calling function.
1165  memmove(ctx->raw_samples[c] - sconf->max_order,
1166  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1167  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1168 
1169  return 0;
1170 }
1171 
1172 
1173 /** Read the channel data.
1174  */
1175 static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)
1176 {
1177  GetBitContext *gb = &ctx->gb;
1178  ALSChannelData *current = cd;
1179  unsigned int channels = ctx->avctx->channels;
1180  int entries = 0;
1181 
1182  while (entries < channels && !(current->stop_flag = get_bits1(gb))) {
1183  current->master_channel = get_bits_long(gb, av_ceil_log2(channels));
1184 
1185  if (current->master_channel >= channels) {
1186  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n");
1187  return -1;
1188  }
1189 
1190  if (current->master_channel != c) {
1191  current->time_diff_flag = get_bits1(gb);
1192  current->weighting[0] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1193  current->weighting[1] = mcc_weightings[av_clip(decode_rice(gb, 2) + 14, 0, 31)];
1194  current->weighting[2] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1195 
1196  if (current->time_diff_flag) {
1197  current->weighting[3] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1198  current->weighting[4] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1199  current->weighting[5] = mcc_weightings[av_clip(decode_rice(gb, 1) + 16, 0, 31)];
1200 
1201  current->time_diff_sign = get_bits1(gb);
1202  current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;
1203  }
1204  }
1205 
1206  current++;
1207  entries++;
1208  }
1209 
1210  if (entries == channels) {
1211  av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data.\n");
1212  return -1;
1213  }
1214 
1215  align_get_bits(gb);
1216  return 0;
1217 }
1218 
1219 
1220 /** Recursively reverts the inter-channel correlation for a block.
1221  */
1222 static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,
1223  ALSChannelData **cd, int *reverted,
1224  unsigned int offset, int c)
1225 {
1226  ALSChannelData *ch = cd[c];
1227  unsigned int dep = 0;
1228  unsigned int channels = ctx->avctx->channels;
1229 
1230  if (reverted[c])
1231  return 0;
1232 
1233  reverted[c] = 1;
1234 
1235  while (dep < channels && !ch[dep].stop_flag) {
1236  revert_channel_correlation(ctx, bd, cd, reverted, offset,
1237  ch[dep].master_channel);
1238 
1239  dep++;
1240  }
1241 
1242  if (dep == channels) {
1243  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n");
1244  return -1;
1245  }
1246 
1247  bd->const_block = ctx->const_block + c;
1248  bd->shift_lsbs = ctx->shift_lsbs + c;
1249  bd->opt_order = ctx->opt_order + c;
1250  bd->store_prev_samples = ctx->store_prev_samples + c;
1251  bd->use_ltp = ctx->use_ltp + c;
1252  bd->ltp_lag = ctx->ltp_lag + c;
1253  bd->ltp_gain = ctx->ltp_gain[c];
1254  bd->lpc_cof = ctx->lpc_cof[c];
1255  bd->quant_cof = ctx->quant_cof[c];
1256  bd->raw_samples = ctx->raw_samples[c] + offset;
1257 
1258  dep = 0;
1259  while (!ch[dep].stop_flag) {
1260  unsigned int smp;
1261  unsigned int begin = 1;
1262  unsigned int end = bd->block_length - 1;
1263  int64_t y;
1264  int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;
1265 
1266  if (ch[dep].time_diff_flag) {
1267  int t = ch[dep].time_diff_index;
1268 
1269  if (ch[dep].time_diff_sign) {
1270  t = -t;
1271  begin -= t;
1272  } else {
1273  end -= t;
1274  }
1275 
1276  for (smp = begin; smp < end; smp++) {
1277  y = (1 << 6) +
1278  MUL64(ch[dep].weighting[0], master[smp - 1 ]) +
1279  MUL64(ch[dep].weighting[1], master[smp ]) +
1280  MUL64(ch[dep].weighting[2], master[smp + 1 ]) +
1281  MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +
1282  MUL64(ch[dep].weighting[4], master[smp + t]) +
1283  MUL64(ch[dep].weighting[5], master[smp + 1 + t]);
1284 
1285  bd->raw_samples[smp] += y >> 7;
1286  }
1287  } else {
1288  for (smp = begin; smp < end; smp++) {
1289  y = (1 << 6) +
1290  MUL64(ch[dep].weighting[0], master[smp - 1]) +
1291  MUL64(ch[dep].weighting[1], master[smp ]) +
1292  MUL64(ch[dep].weighting[2], master[smp + 1]);
1293 
1294  bd->raw_samples[smp] += y >> 7;
1295  }
1296  }
1297 
1298  dep++;
1299  }
1300 
1301  return 0;
1302 }
1303 
1304 
1305 /** Read the frame data.
1306  */
1307 static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
1308 {
1309  ALSSpecificConfig *sconf = &ctx->sconf;
1310  AVCodecContext *avctx = ctx->avctx;
1311  GetBitContext *gb = &ctx->gb;
1312  unsigned int div_blocks[32]; ///< block sizes.
1313  unsigned int c;
1314  unsigned int js_blocks[2];
1315 
1316  uint32_t bs_info = 0;
1317 
1318  // skip the size of the ra unit if present in the frame
1319  if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)
1320  skip_bits_long(gb, 32);
1321 
1322  if (sconf->mc_coding && sconf->joint_stereo) {
1323  ctx->js_switch = get_bits1(gb);
1324  align_get_bits(gb);
1325  }
1326 
1327  if (!sconf->mc_coding || ctx->js_switch) {
1328  int independent_bs = !sconf->joint_stereo;
1329 
1330  for (c = 0; c < avctx->channels; c++) {
1331  js_blocks[0] = 0;
1332  js_blocks[1] = 0;
1333 
1334  get_block_sizes(ctx, div_blocks, &bs_info);
1335 
1336  // if joint_stereo and block_switching is set, independent decoding
1337  // is signaled via the first bit of bs_info
1338  if (sconf->joint_stereo && sconf->block_switching)
1339  if (bs_info >> 31)
1340  independent_bs = 2;
1341 
1342  // if this is the last channel, it has to be decoded independently
1343  if (c == avctx->channels - 1)
1344  independent_bs = 1;
1345 
1346  if (independent_bs) {
1347  if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))
1348  return -1;
1349 
1350  independent_bs--;
1351  } else {
1352  if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))
1353  return -1;
1354 
1355  c++;
1356  }
1357 
1358  // store carryover raw samples
1359  memmove(ctx->raw_samples[c] - sconf->max_order,
1360  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1361  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1362  }
1363  } else { // multi-channel coding
1364  ALSBlockData bd = { 0 };
1365  int b, ret;
1366  int *reverted_channels = ctx->reverted_channels;
1367  unsigned int offset = 0;
1368 
1369  for (c = 0; c < avctx->channels; c++)
1370  if (ctx->chan_data[c] < ctx->chan_data_buffer) {
1371  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n");
1372  return -1;
1373  }
1374 
1375  memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);
1376 
1377  bd.ra_block = ra_frame;
1378  bd.prev_raw_samples = ctx->prev_raw_samples;
1379 
1380  get_block_sizes(ctx, div_blocks, &bs_info);
1381 
1382  for (b = 0; b < ctx->num_blocks; b++) {
1383  bd.block_length = div_blocks[b];
1384 
1385  for (c = 0; c < avctx->channels; c++) {
1386  bd.const_block = ctx->const_block + c;
1387  bd.shift_lsbs = ctx->shift_lsbs + c;
1388  bd.opt_order = ctx->opt_order + c;
1389  bd.store_prev_samples = ctx->store_prev_samples + c;
1390  bd.use_ltp = ctx->use_ltp + c;
1391  bd.ltp_lag = ctx->ltp_lag + c;
1392  bd.ltp_gain = ctx->ltp_gain[c];
1393  bd.lpc_cof = ctx->lpc_cof[c];
1394  bd.quant_cof = ctx->quant_cof[c];
1395  bd.raw_samples = ctx->raw_samples[c] + offset;
1396  bd.raw_other = NULL;
1397 
1398  if ((ret = read_block(ctx, &bd)) < 0)
1399  return ret;
1400  if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)
1401  return ret;
1402  }
1403 
1404  for (c = 0; c < avctx->channels; c++)
1405  if (revert_channel_correlation(ctx, &bd, ctx->chan_data,
1406  reverted_channels, offset, c))
1407  return -1;
1408 
1409  for (c = 0; c < avctx->channels; c++) {
1410  bd.const_block = ctx->const_block + c;
1411  bd.shift_lsbs = ctx->shift_lsbs + c;
1412  bd.opt_order = ctx->opt_order + c;
1413  bd.store_prev_samples = ctx->store_prev_samples + c;
1414  bd.use_ltp = ctx->use_ltp + c;
1415  bd.ltp_lag = ctx->ltp_lag + c;
1416  bd.ltp_gain = ctx->ltp_gain[c];
1417  bd.lpc_cof = ctx->lpc_cof[c];
1418  bd.quant_cof = ctx->quant_cof[c];
1419  bd.raw_samples = ctx->raw_samples[c] + offset;
1420 
1421  if ((ret = decode_block(ctx, &bd)) < 0)
1422  return ret;
1423  }
1424 
1425  memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));
1426  offset += div_blocks[b];
1427  bd.ra_block = 0;
1428  }
1429 
1430  // store carryover raw samples
1431  for (c = 0; c < avctx->channels; c++)
1432  memmove(ctx->raw_samples[c] - sconf->max_order,
1433  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1434  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1435  }
1436 
1437  // TODO: read_diff_float_data
1438 
1439  return 0;
1440 }
1441 
1442 
1443 /** Decode an ALS frame.
1444  */
1445 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
1446  AVPacket *avpkt)
1447 {
1448  ALSDecContext *ctx = avctx->priv_data;
1449  AVFrame *frame = data;
1450  ALSSpecificConfig *sconf = &ctx->sconf;
1451  const uint8_t *buffer = avpkt->data;
1452  int buffer_size = avpkt->size;
1453  int invalid_frame, ret;
1454  unsigned int c, sample, ra_frame, bytes_read, shift;
1455 
1456  init_get_bits(&ctx->gb, buffer, buffer_size * 8);
1457 
1458  // In the case that the distance between random access frames is set to zero
1459  // (sconf->ra_distance == 0) no frame is treated as a random access frame.
1460  // For the first frame, if prediction is used, all samples used from the
1461  // previous frame are assumed to be zero.
1462  ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);
1463 
1464  // the last frame to decode might have a different length
1465  if (sconf->samples != 0xFFFFFFFF)
1466  ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,
1467  sconf->frame_length);
1468  else
1469  ctx->cur_frame_length = sconf->frame_length;
1470 
1471  // decode the frame data
1472  if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)
1473  av_log(ctx->avctx, AV_LOG_WARNING,
1474  "Reading frame data failed. Skipping RA unit.\n");
1475 
1476  ctx->frame_id++;
1477 
1478  /* get output buffer */
1479  frame->nb_samples = ctx->cur_frame_length;
1480  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1481  return ret;
1482 
1483  // transform decoded frame into output format
1484  #define INTERLEAVE_OUTPUT(bps) \
1485  { \
1486  int##bps##_t *dest = (int##bps##_t*)frame->data[0]; \
1487  shift = bps - ctx->avctx->bits_per_raw_sample; \
1488  if (!ctx->cs_switch) { \
1489  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1490  for (c = 0; c < avctx->channels; c++) \
1491  *dest++ = ctx->raw_samples[c][sample] << shift; \
1492  } else { \
1493  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1494  for (c = 0; c < avctx->channels; c++) \
1495  *dest++ = ctx->raw_samples[sconf->chan_pos[c]][sample] << shift; \
1496  } \
1497  }
1498 
1499  if (ctx->avctx->bits_per_raw_sample <= 16) {
1500  INTERLEAVE_OUTPUT(16)
1501  } else {
1502  INTERLEAVE_OUTPUT(32)
1503  }
1504 
1505  // update CRC
1506  if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1507  int swap = HAVE_BIGENDIAN != sconf->msb_first;
1508 
1509  if (ctx->avctx->bits_per_raw_sample == 24) {
1510  int32_t *src = (int32_t *)frame->data[0];
1511 
1512  for (sample = 0;
1513  sample < ctx->cur_frame_length * avctx->channels;
1514  sample++) {
1515  int32_t v;
1516 
1517  if (swap)
1518  v = av_bswap32(src[sample]);
1519  else
1520  v = src[sample];
1521  if (!HAVE_BIGENDIAN)
1522  v >>= 8;
1523 
1524  ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);
1525  }
1526  } else {
1527  uint8_t *crc_source;
1528 
1529  if (swap) {
1530  if (ctx->avctx->bits_per_raw_sample <= 16) {
1531  int16_t *src = (int16_t*) frame->data[0];
1532  int16_t *dest = (int16_t*) ctx->crc_buffer;
1533  for (sample = 0;
1534  sample < ctx->cur_frame_length * avctx->channels;
1535  sample++)
1536  *dest++ = av_bswap16(src[sample]);
1537  } else {
1538  ctx->dsp.bswap_buf((uint32_t*)ctx->crc_buffer,
1539  (uint32_t *)frame->data[0],
1540  ctx->cur_frame_length * avctx->channels);
1541  }
1542  crc_source = ctx->crc_buffer;
1543  } else {
1544  crc_source = frame->data[0];
1545  }
1546 
1547  ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,
1548  ctx->cur_frame_length * avctx->channels *
1549  av_get_bytes_per_sample(avctx->sample_fmt));
1550  }
1551 
1552 
1553  // check CRC sums if this is the last frame
1554  if (ctx->cur_frame_length != sconf->frame_length &&
1555  ctx->crc_org != ctx->crc) {
1556  av_log(avctx, AV_LOG_ERROR, "CRC error.\n");
1557  }
1558  }
1559 
1560  *got_frame_ptr = 1;
1561 
1562  bytes_read = invalid_frame ? buffer_size :
1563  (get_bits_count(&ctx->gb) + 7) >> 3;
1564 
1565  return bytes_read;
1566 }
1567 
1568 
1569 /** Uninitialize the ALS decoder.
1570  */
1571 static av_cold int decode_end(AVCodecContext *avctx)
1572 {
1573  ALSDecContext *ctx = avctx->priv_data;
1574 
1575  av_freep(&ctx->sconf.chan_pos);
1576 
1577  ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);
1578 
1579  av_freep(&ctx->const_block);
1580  av_freep(&ctx->shift_lsbs);
1581  av_freep(&ctx->opt_order);
1582  av_freep(&ctx->store_prev_samples);
1583  av_freep(&ctx->use_ltp);
1584  av_freep(&ctx->ltp_lag);
1585  av_freep(&ctx->ltp_gain);
1586  av_freep(&ctx->ltp_gain_buffer);
1587  av_freep(&ctx->quant_cof);
1588  av_freep(&ctx->lpc_cof);
1589  av_freep(&ctx->quant_cof_buffer);
1590  av_freep(&ctx->lpc_cof_buffer);
1591  av_freep(&ctx->lpc_cof_reversed_buffer);
1592  av_freep(&ctx->prev_raw_samples);
1593  av_freep(&ctx->raw_samples);
1594  av_freep(&ctx->raw_buffer);
1595  av_freep(&ctx->chan_data);
1596  av_freep(&ctx->chan_data_buffer);
1597  av_freep(&ctx->reverted_channels);
1598  av_freep(&ctx->crc_buffer);
1599 
1600  return 0;
1601 }
1602 
1603 
1604 /** Initialize the ALS decoder.
1605  */
1606 static av_cold int decode_init(AVCodecContext *avctx)
1607 {
1608  unsigned int c;
1609  unsigned int channel_size;
1610  int num_buffers;
1611  ALSDecContext *ctx = avctx->priv_data;
1612  ALSSpecificConfig *sconf = &ctx->sconf;
1613  ctx->avctx = avctx;
1614 
1615  if (!avctx->extradata) {
1616  av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");
1617  return -1;
1618  }
1619 
1620  if (read_specific_config(ctx)) {
1621  av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");
1622  decode_end(avctx);
1623  return -1;
1624  }
1625 
1626  if (check_specific_config(ctx)) {
1627  decode_end(avctx);
1628  return -1;
1629  }
1630 
1631  if (sconf->bgmc)
1632  ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);
1633 
1634  if (sconf->floating) {
1635  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
1636  avctx->bits_per_raw_sample = 32;
1637  } else {
1638  avctx->sample_fmt = sconf->resolution > 1
1639  ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
1640  avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;
1641  }
1642 
1643  // set maximum Rice parameter for progressive decoding based on resolution
1644  // This is not specified in 14496-3 but actually done by the reference
1645  // codec RM22 revision 2.
1646  ctx->s_max = sconf->resolution > 1 ? 31 : 15;
1647 
1648  // set lag value for long-term prediction
1649  ctx->ltp_lag_length = 8 + (avctx->sample_rate >= 96000) +
1650  (avctx->sample_rate >= 192000);
1651 
1652  // allocate quantized parcor coefficient buffer
1653  num_buffers = sconf->mc_coding ? avctx->channels : 1;
1654 
1655  ctx->quant_cof = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);
1656  ctx->lpc_cof = av_malloc(sizeof(*ctx->lpc_cof) * num_buffers);
1657  ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *
1658  num_buffers * sconf->max_order);
1659  ctx->lpc_cof_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *
1660  num_buffers * sconf->max_order);
1661  ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *
1662  sconf->max_order);
1663 
1664  if (!ctx->quant_cof || !ctx->lpc_cof ||
1665  !ctx->quant_cof_buffer || !ctx->lpc_cof_buffer ||
1666  !ctx->lpc_cof_reversed_buffer) {
1667  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1668  return AVERROR(ENOMEM);
1669  }
1670 
1671  // assign quantized parcor coefficient buffers
1672  for (c = 0; c < num_buffers; c++) {
1673  ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;
1674  ctx->lpc_cof[c] = ctx->lpc_cof_buffer + c * sconf->max_order;
1675  }
1676 
1677  // allocate and assign lag and gain data buffer for ltp mode
1678  ctx->const_block = av_malloc (sizeof(*ctx->const_block) * num_buffers);
1679  ctx->shift_lsbs = av_malloc (sizeof(*ctx->shift_lsbs) * num_buffers);
1680  ctx->opt_order = av_malloc (sizeof(*ctx->opt_order) * num_buffers);
1681  ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);
1682  ctx->use_ltp = av_mallocz(sizeof(*ctx->use_ltp) * num_buffers);
1683  ctx->ltp_lag = av_malloc (sizeof(*ctx->ltp_lag) * num_buffers);
1684  ctx->ltp_gain = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);
1685  ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *
1686  num_buffers * 5);
1687 
1688  if (!ctx->const_block || !ctx->shift_lsbs ||
1689  !ctx->opt_order || !ctx->store_prev_samples ||
1690  !ctx->use_ltp || !ctx->ltp_lag ||
1691  !ctx->ltp_gain || !ctx->ltp_gain_buffer) {
1692  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1693  decode_end(avctx);
1694  return AVERROR(ENOMEM);
1695  }
1696 
1697  for (c = 0; c < num_buffers; c++)
1698  ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;
1699 
1700  // allocate and assign channel data buffer for mcc mode
1701  if (sconf->mc_coding) {
1702  ctx->chan_data_buffer = av_malloc(sizeof(*ctx->chan_data_buffer) *
1703  num_buffers * num_buffers);
1704  ctx->chan_data = av_malloc(sizeof(*ctx->chan_data) *
1705  num_buffers);
1706  ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *
1707  num_buffers);
1708 
1709  if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {
1710  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1711  decode_end(avctx);
1712  return AVERROR(ENOMEM);
1713  }
1714 
1715  for (c = 0; c < num_buffers; c++)
1716  ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;
1717  } else {
1718  ctx->chan_data = NULL;
1719  ctx->chan_data_buffer = NULL;
1720  ctx->reverted_channels = NULL;
1721  }
1722 
1723  channel_size = sconf->frame_length + sconf->max_order;
1724 
1725  ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);
1726  ctx->raw_buffer = av_mallocz(sizeof(*ctx-> raw_buffer) * avctx->channels * channel_size);
1727  ctx->raw_samples = av_malloc (sizeof(*ctx-> raw_samples) * avctx->channels);
1728 
1729  // allocate previous raw sample buffer
1730  if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {
1731  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1732  decode_end(avctx);
1733  return AVERROR(ENOMEM);
1734  }
1735 
1736  // assign raw samples buffers
1737  ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;
1738  for (c = 1; c < avctx->channels; c++)
1739  ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;
1740 
1741  // allocate crc buffer
1742  if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&
1743  (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1744  ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *
1745  ctx->cur_frame_length *
1746  avctx->channels *
1747  av_get_bytes_per_sample(avctx->sample_fmt));
1748  if (!ctx->crc_buffer) {
1749  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1750  decode_end(avctx);
1751  return AVERROR(ENOMEM);
1752  }
1753  }
1754 
1755  ff_dsputil_init(&ctx->dsp, avctx);
1756 
1757  return 0;
1758 }
1759 
1760 
1761 /** Flush (reset) the frame ID after seeking.
1762  */
1763 static av_cold void flush(AVCodecContext *avctx)
1764 {
1765  ALSDecContext *ctx = avctx->priv_data;
1766 
1767  ctx->frame_id = 0;
1768 }
1769 
1770 
1771 AVCodec ff_als_decoder = {
1772  .name = "als",
1773  .type = AVMEDIA_TYPE_AUDIO,
1774  .id = AV_CODEC_ID_MP4ALS,
1775  .priv_data_size = sizeof(ALSDecContext),
1776  .init = decode_init,
1777  .close = decode_end,
1778  .decode = decode_frame,
1779  .flush = flush,
1780  .capabilities = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
1781  .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),
1782 };
Generated on Wed Jul 10 2013 23:47:55 for FFmpeg by   doxygen 1.8.2