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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_ mail.de>
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_ mail.de>
26  */
27 
28 #include <inttypes.h>
29 
30 #include "avcodec.h"
31 #include "get_bits.h"
32 #include "unary.h"
33 #include "mpeg4audio.h"
34 #include "bytestream.h"
35 #include "bgmc.h"
36 #include "bswapdsp.h"
37 #include "internal.h"
38 #include "libavutil/samplefmt.h"
39 #include "libavutil/crc.h"
40 
41 #include <stdint.h>
42 
43 /** Rice parameters and corresponding index offsets for decoding the
44  * indices of scaled PARCOR values. The table chosen is set globally
45  * by the encoder and stored in ALSSpecificConfig.
46  */
47 static const int8_t parcor_rice_table[3][20][2] = {
48  { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},
49  { 12, 3}, { -7, 3}, { 9, 3}, { -5, 3}, { 6, 3},
50  { -4, 3}, { 3, 3}, { -3, 2}, { 3, 2}, { -2, 2},
51  { 3, 2}, { -1, 2}, { 2, 2}, { -1, 2}, { 2, 2} },
52  { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},
53  { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},
54  {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},
55  { 7, 3}, { -4, 4}, { 3, 3}, { -1, 3}, { 1, 3} },
56  { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},
57  { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},
58  {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},
59  { 3, 3}, { 0, 3}, { -1, 3}, { 2, 3}, { -1, 2} }
60 };
61 
62 
63 /** Scaled PARCOR values used for the first two PARCOR coefficients.
64  * To be indexed by the Rice coded indices.
65  * Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20)
66  * Actual values are divided by 32 in order to be stored in 16 bits.
67  */
68 static const int16_t parcor_scaled_values[] = {
69  -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,
70  -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,
71  -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,
72  -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,
73  -1013728 / 32, -1009376 / 32, -1004768 / 32, -999904 / 32,
74  -994784 / 32, -989408 / 32, -983776 / 32, -977888 / 32,
75  -971744 / 32, -965344 / 32, -958688 / 32, -951776 / 32,
76  -944608 / 32, -937184 / 32, -929504 / 32, -921568 / 32,
77  -913376 / 32, -904928 / 32, -896224 / 32, -887264 / 32,
78  -878048 / 32, -868576 / 32, -858848 / 32, -848864 / 32,
79  -838624 / 32, -828128 / 32, -817376 / 32, -806368 / 32,
80  -795104 / 32, -783584 / 32, -771808 / 32, -759776 / 32,
81  -747488 / 32, -734944 / 32, -722144 / 32, -709088 / 32,
82  -695776 / 32, -682208 / 32, -668384 / 32, -654304 / 32,
83  -639968 / 32, -625376 / 32, -610528 / 32, -595424 / 32,
84  -580064 / 32, -564448 / 32, -548576 / 32, -532448 / 32,
85  -516064 / 32, -499424 / 32, -482528 / 32, -465376 / 32,
86  -447968 / 32, -430304 / 32, -412384 / 32, -394208 / 32,
87  -375776 / 32, -357088 / 32, -338144 / 32, -318944 / 32,
88  -299488 / 32, -279776 / 32, -259808 / 32, -239584 / 32,
89  -219104 / 32, -198368 / 32, -177376 / 32, -156128 / 32,
90  -134624 / 32, -112864 / 32, -90848 / 32, -68576 / 32,
91  -46048 / 32, -23264 / 32, -224 / 32, 23072 / 32,
92  46624 / 32, 70432 / 32, 94496 / 32, 118816 / 32,
93  143392 / 32, 168224 / 32, 193312 / 32, 218656 / 32,
94  244256 / 32, 270112 / 32, 296224 / 32, 322592 / 32,
95  349216 / 32, 376096 / 32, 403232 / 32, 430624 / 32,
96  458272 / 32, 486176 / 32, 514336 / 32, 542752 / 32,
97  571424 / 32, 600352 / 32, 629536 / 32, 658976 / 32,
98  688672 / 32, 718624 / 32, 748832 / 32, 779296 / 32,
99  810016 / 32, 840992 / 32, 872224 / 32, 903712 / 32,
100  935456 / 32, 967456 / 32, 999712 / 32, 1032224 / 32
101 };
102 
103 
104 /** Gain values of p(0) for long-term prediction.
105  * To be indexed by the Rice coded indices.
106  */
107 static const uint8_t ltp_gain_values [4][4] = {
108  { 0, 8, 16, 24},
109  {32, 40, 48, 56},
110  {64, 70, 76, 82},
111  {88, 92, 96, 100}
112 };
113 
114 
115 /** Inter-channel weighting factors for multi-channel correlation.
116  * To be indexed by the Rice coded indices.
117  */
118 static const int16_t mcc_weightings[] = {
119  204, 192, 179, 166, 153, 140, 128, 115,
120  102, 89, 76, 64, 51, 38, 25, 12,
121  0, -12, -25, -38, -51, -64, -76, -89,
122  -102, -115, -128, -140, -153, -166, -179, -192
123 };
124 
125 
126 /** Tail codes used in arithmetic coding using block Gilbert-Moore codes.
127  */
128 static const uint8_t tail_code[16][6] = {
129  { 74, 44, 25, 13, 7, 3},
130  { 68, 42, 24, 13, 7, 3},
131  { 58, 39, 23, 13, 7, 3},
132  {126, 70, 37, 19, 10, 5},
133  {132, 70, 37, 20, 10, 5},
134  {124, 70, 38, 20, 10, 5},
135  {120, 69, 37, 20, 11, 5},
136  {116, 67, 37, 20, 11, 5},
137  {108, 66, 36, 20, 10, 5},
138  {102, 62, 36, 20, 10, 5},
139  { 88, 58, 34, 19, 10, 5},
140  {162, 89, 49, 25, 13, 7},
141  {156, 87, 49, 26, 14, 7},
142  {150, 86, 47, 26, 14, 7},
143  {142, 84, 47, 26, 14, 7},
144  {131, 79, 46, 26, 14, 7}
145 };
146 
147 
148 enum RA_Flag {
149  RA_FLAG_NONE,
150  RA_FLAG_FRAMES,
151  RA_FLAG_HEADER
152 };
153 
154 
155 typedef struct ALSSpecificConfig {
156  uint32_t samples; ///< number of samples, 0xFFFFFFFF if unknown
157  int resolution; ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit
158  int floating; ///< 1 = IEEE 32-bit floating-point, 0 = integer
159  int msb_first; ///< 1 = original CRC calculated on big-endian system, 0 = little-endian
160  int frame_length; ///< frame length for each frame (last frame may differ)
161  int ra_distance; ///< distance between RA frames (in frames, 0...255)
162  enum RA_Flag ra_flag; ///< indicates where the size of ra units is stored
163  int adapt_order; ///< adaptive order: 1 = on, 0 = off
164  int coef_table; ///< table index of Rice code parameters
165  int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off
166  int max_order; ///< maximum prediction order (0..1023)
167  int block_switching; ///< number of block switching levels
168  int bgmc; ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)
169  int sb_part; ///< sub-block partition
170  int joint_stereo; ///< joint stereo: 1 = on, 0 = off
171  int mc_coding; ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off
172  int chan_config; ///< indicates that a chan_config_info field is present
173  int chan_sort; ///< channel rearrangement: 1 = on, 0 = off
174  int rlslms; ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off
175  int chan_config_info; ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.
176  int *chan_pos; ///< original channel positions
177  int crc_enabled; ///< enable Cyclic Redundancy Checksum
178 } ALSSpecificConfig;
179 
180 
181 typedef struct ALSChannelData {
182  int stop_flag;
183  int master_channel;
184  int time_diff_flag;
185  int time_diff_sign;
186  int time_diff_index;
187  int weighting[6];
188 } ALSChannelData;
189 
190 
191 typedef struct ALSDecContext {
192  AVCodecContext *avctx;
193  ALSSpecificConfig sconf;
194  GetBitContext gb;
195  BswapDSPContext bdsp;
196  const AVCRC *crc_table;
197  uint32_t crc_org; ///< CRC value of the original input data
198  uint32_t crc; ///< CRC value calculated from decoded data
199  unsigned int cur_frame_length; ///< length of the current frame to decode
200  unsigned int frame_id; ///< the frame ID / number of the current frame
201  unsigned int js_switch; ///< if true, joint-stereo decoding is enforced
202  unsigned int cs_switch; ///< if true, channel rearrangement is done
203  unsigned int num_blocks; ///< number of blocks used in the current frame
204  unsigned int s_max; ///< maximum Rice parameter allowed in entropy coding
205  uint8_t *bgmc_lut; ///< pointer at lookup tables used for BGMC
206  int *bgmc_lut_status; ///< pointer at lookup table status flags used for BGMC
207  int ltp_lag_length; ///< number of bits used for ltp lag value
208  int *const_block; ///< contains const_block flags for all channels
209  unsigned int *shift_lsbs; ///< contains shift_lsbs flags for all channels
210  unsigned int *opt_order; ///< contains opt_order flags for all channels
211  int *store_prev_samples; ///< contains store_prev_samples flags for all channels
212  int *use_ltp; ///< contains use_ltp flags for all channels
213  int *ltp_lag; ///< contains ltp lag values for all channels
214  int **ltp_gain; ///< gain values for ltp 5-tap filter for a channel
215  int *ltp_gain_buffer; ///< contains all gain values for ltp 5-tap filter
216  int32_t **quant_cof; ///< quantized parcor coefficients for a channel
217  int32_t *quant_cof_buffer; ///< contains all quantized parcor coefficients
218  int32_t **lpc_cof; ///< coefficients of the direct form prediction filter for a channel
219  int32_t *lpc_cof_buffer; ///< contains all coefficients of the direct form prediction filter
220  int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer
221  ALSChannelData **chan_data; ///< channel data for multi-channel correlation
222  ALSChannelData *chan_data_buffer; ///< contains channel data for all channels
223  int *reverted_channels; ///< stores a flag for each reverted channel
224  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
225  int32_t **raw_samples; ///< decoded raw samples for each channel
226  int32_t *raw_buffer; ///< contains all decoded raw samples including carryover samples
227  uint8_t *crc_buffer; ///< buffer of byte order corrected samples used for CRC check
228 } ALSDecContext;
229 
230 
231 typedef struct ALSBlockData {
232  unsigned int block_length; ///< number of samples within the block
233  unsigned int ra_block; ///< if true, this is a random access block
234  int *const_block; ///< if true, this is a constant value block
235  int js_blocks; ///< true if this block contains a difference signal
236  unsigned int *shift_lsbs; ///< shift of values for this block
237  unsigned int *opt_order; ///< prediction order of this block
238  int *store_prev_samples;///< if true, carryover samples have to be stored
239  int *use_ltp; ///< if true, long-term prediction is used
240  int *ltp_lag; ///< lag value for long-term prediction
241  int *ltp_gain; ///< gain values for ltp 5-tap filter
242  int32_t *quant_cof; ///< quantized parcor coefficients
243  int32_t *lpc_cof; ///< coefficients of the direct form prediction
244  int32_t *raw_samples; ///< decoded raw samples / residuals for this block
245  int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
246  int32_t *raw_other; ///< decoded raw samples of the other channel of a channel pair
247 } ALSBlockData;
248 
249 
250 static av_cold void dprint_specific_config(ALSDecContext *ctx)
251 {
252 #ifdef DEBUG
253  AVCodecContext *avctx = ctx->avctx;
254  ALSSpecificConfig *sconf = &ctx->sconf;
255 
256  av_dlog(avctx, "resolution = %i\n", sconf->resolution);
257  av_dlog(avctx, "floating = %i\n", sconf->floating);
258  av_dlog(avctx, "frame_length = %i\n", sconf->frame_length);
259  av_dlog(avctx, "ra_distance = %i\n", sconf->ra_distance);
260  av_dlog(avctx, "ra_flag = %i\n", sconf->ra_flag);
261  av_dlog(avctx, "adapt_order = %i\n", sconf->adapt_order);
262  av_dlog(avctx, "coef_table = %i\n", sconf->coef_table);
263  av_dlog(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);
264  av_dlog(avctx, "max_order = %i\n", sconf->max_order);
265  av_dlog(avctx, "block_switching = %i\n", sconf->block_switching);
266  av_dlog(avctx, "bgmc = %i\n", sconf->bgmc);
267  av_dlog(avctx, "sb_part = %i\n", sconf->sb_part);
268  av_dlog(avctx, "joint_stereo = %i\n", sconf->joint_stereo);
269  av_dlog(avctx, "mc_coding = %i\n", sconf->mc_coding);
270  av_dlog(avctx, "chan_config = %i\n", sconf->chan_config);
271  av_dlog(avctx, "chan_sort = %i\n", sconf->chan_sort);
272  av_dlog(avctx, "RLSLMS = %i\n", sconf->rlslms);
273  av_dlog(avctx, "chan_config_info = %i\n", sconf->chan_config_info);
274 #endif
275 }
276 
277 
278 /** Read an ALSSpecificConfig from a buffer into the output struct.
279  */
280 static av_cold int read_specific_config(ALSDecContext *ctx)
281 {
282  GetBitContext gb;
283  uint64_t ht_size;
284  int i, config_offset;
285  MPEG4AudioConfig m4ac = {0};
286  ALSSpecificConfig *sconf = &ctx->sconf;
287  AVCodecContext *avctx = ctx->avctx;
288  uint32_t als_id, header_size, trailer_size;
289  int ret;
290 
291  if ((ret = init_get_bits8(&gb, avctx->extradata, avctx->extradata_size)) < 0)
292  return ret;
293 
294  config_offset = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata,
295  avctx->extradata_size * 8, 1);
296 
297  if (config_offset < 0)
298  return AVERROR_INVALIDDATA;
299 
300  skip_bits_long(&gb, config_offset);
301 
302  if (get_bits_left(&gb) < (30 << 3))
303  return AVERROR_INVALIDDATA;
304 
305  // read the fixed items
306  als_id = get_bits_long(&gb, 32);
307  avctx->sample_rate = m4ac.sample_rate;
308  skip_bits_long(&gb, 32); // sample rate already known
309  sconf->samples = get_bits_long(&gb, 32);
310  avctx->channels = m4ac.channels;
311  skip_bits(&gb, 16); // number of channels already known
312  skip_bits(&gb, 3); // skip file_type
313  sconf->resolution = get_bits(&gb, 3);
314  sconf->floating = get_bits1(&gb);
315  sconf->msb_first = get_bits1(&gb);
316  sconf->frame_length = get_bits(&gb, 16) + 1;
317  sconf->ra_distance = get_bits(&gb, 8);
318  sconf->ra_flag = get_bits(&gb, 2);
319  sconf->adapt_order = get_bits1(&gb);
320  sconf->coef_table = get_bits(&gb, 2);
321  sconf->long_term_prediction = get_bits1(&gb);
322  sconf->max_order = get_bits(&gb, 10);
323  sconf->block_switching = get_bits(&gb, 2);
324  sconf->bgmc = get_bits1(&gb);
325  sconf->sb_part = get_bits1(&gb);
326  sconf->joint_stereo = get_bits1(&gb);
327  sconf->mc_coding = get_bits1(&gb);
328  sconf->chan_config = get_bits1(&gb);
329  sconf->chan_sort = get_bits1(&gb);
330  sconf->crc_enabled = get_bits1(&gb);
331  sconf->rlslms = get_bits1(&gb);
332  skip_bits(&gb, 5); // skip 5 reserved bits
333  skip_bits1(&gb); // skip aux_data_enabled
334 
335 
336  // check for ALSSpecificConfig struct
337  if (als_id != MKBETAG('A','L','S','\0'))
338  return AVERROR_INVALIDDATA;
339 
340  ctx->cur_frame_length = sconf->frame_length;
341 
342  // read channel config
343  if (sconf->chan_config)
344  sconf->chan_config_info = get_bits(&gb, 16);
345  // TODO: use this to set avctx->channel_layout
346 
347 
348  // read channel sorting
349  if (sconf->chan_sort && avctx->channels > 1) {
350  int chan_pos_bits = av_ceil_log2(avctx->channels);
351  int bits_needed = avctx->channels * chan_pos_bits + 7;
352  if (get_bits_left(&gb) < bits_needed)
353  return AVERROR_INVALIDDATA;
354 
355  if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))
356  return AVERROR(ENOMEM);
357 
358  ctx->cs_switch = 1;
359 
360  for (i = 0; i < avctx->channels; i++) {
361  int idx;
362 
363  idx = get_bits(&gb, chan_pos_bits);
364  if (idx >= avctx->channels) {
365  av_log(avctx, AV_LOG_WARNING, "Invalid channel reordering.\n");
366  ctx->cs_switch = 0;
367  break;
368  }
369  sconf->chan_pos[idx] = i;
370  }
371 
372  align_get_bits(&gb);
373  }
374 
375 
376  // read fixed header and trailer sizes,
377  // if size = 0xFFFFFFFF then there is no data field!
378  if (get_bits_left(&gb) < 64)
379  return AVERROR_INVALIDDATA;
380 
381  header_size = get_bits_long(&gb, 32);
382  trailer_size = get_bits_long(&gb, 32);
383  if (header_size == 0xFFFFFFFF)
384  header_size = 0;
385  if (trailer_size == 0xFFFFFFFF)
386  trailer_size = 0;
387 
388  ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3;
389 
390 
391  // skip the header and trailer data
392  if (get_bits_left(&gb) < ht_size)
393  return AVERROR_INVALIDDATA;
394 
395  if (ht_size > INT32_MAX)
396  return AVERROR_PATCHWELCOME;
397 
398  skip_bits_long(&gb, ht_size);
399 
400 
401  // initialize CRC calculation
402  if (sconf->crc_enabled) {
403  if (get_bits_left(&gb) < 32)
404  return AVERROR_INVALIDDATA;
405 
406  if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
407  ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
408  ctx->crc = 0xFFFFFFFF;
409  ctx->crc_org = ~get_bits_long(&gb, 32);
410  } else
411  skip_bits_long(&gb, 32);
412  }
413 
414 
415  // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)
416 
417  dprint_specific_config(ctx);
418 
419  return 0;
420 }
421 
422 
423 /** Check the ALSSpecificConfig for unsupported features.
424  */
425 static int check_specific_config(ALSDecContext *ctx)
426 {
427  ALSSpecificConfig *sconf = &ctx->sconf;
428  int error = 0;
429 
430  // report unsupported feature and set error value
431  #define MISSING_ERR(cond, str, errval) \
432  { \
433  if (cond) { \
434  avpriv_report_missing_feature(ctx->avctx, \
435  str); \
436  error = errval; \
437  } \
438  }
439 
440  MISSING_ERR(sconf->floating, "Floating point decoding", AVERROR_PATCHWELCOME);
441  MISSING_ERR(sconf->rlslms, "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME);
442 
443  return error;
444 }
445 
446 
447 /** Parse the bs_info field to extract the block partitioning used in
448  * block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.
449  */
450 static void parse_bs_info(const uint32_t bs_info, unsigned int n,
451  unsigned int div, unsigned int **div_blocks,
452  unsigned int *num_blocks)
453 {
454  if (n < 31 && ((bs_info << n) & 0x40000000)) {
455  // if the level is valid and the investigated bit n is set
456  // then recursively check both children at bits (2n+1) and (2n+2)
457  n *= 2;
458  div += 1;
459  parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);
460  parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);
461  } else {
462  // else the bit is not set or the last level has been reached
463  // (bit implicitly not set)
464  **div_blocks = div;
465  (*div_blocks)++;
466  (*num_blocks)++;
467  }
468 }
469 
470 
471 /** Read and decode a Rice codeword.
472  */
473 static int32_t decode_rice(GetBitContext *gb, unsigned int k)
474 {
475  int max = get_bits_left(gb) - k;
476  int q = get_unary(gb, 0, max);
477  int r = k ? get_bits1(gb) : !(q & 1);
478 
479  if (k > 1) {
480  q <<= (k - 1);
481  q += get_bits_long(gb, k - 1);
482  } else if (!k) {
483  q >>= 1;
484  }
485  return r ? q : ~q;
486 }
487 
488 
489 /** Convert PARCOR coefficient k to direct filter coefficient.
490  */
491 static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)
492 {
493  int i, j;
494 
495  for (i = 0, j = k - 1; i < j; i++, j--) {
496  int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
497  cof[j] += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);
498  cof[i] += tmp1;
499  }
500  if (i == j)
501  cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
502 
503  cof[k] = par[k];
504 }
505 
506 
507 /** Read block switching field if necessary and set actual block sizes.
508  * Also assure that the block sizes of the last frame correspond to the
509  * actual number of samples.
510  */
511 static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
512  uint32_t *bs_info)
513 {
514  ALSSpecificConfig *sconf = &ctx->sconf;
515  GetBitContext *gb = &ctx->gb;
516  unsigned int *ptr_div_blocks = div_blocks;
517  unsigned int b;
518 
519  if (sconf->block_switching) {
520  unsigned int bs_info_len = 1 << (sconf->block_switching + 2);
521  *bs_info = get_bits_long(gb, bs_info_len);
522  *bs_info <<= (32 - bs_info_len);
523  }
524 
525  ctx->num_blocks = 0;
526  parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);
527 
528  // The last frame may have an overdetermined block structure given in
529  // the bitstream. In that case the defined block structure would need
530  // more samples than available to be consistent.
531  // The block structure is actually used but the block sizes are adapted
532  // to fit the actual number of available samples.
533  // Example: 5 samples, 2nd level block sizes: 2 2 2 2.
534  // This results in the actual block sizes: 2 2 1 0.
535  // This is not specified in 14496-3 but actually done by the reference
536  // codec RM22 revision 2.
537  // This appears to happen in case of an odd number of samples in the last
538  // frame which is actually not allowed by the block length switching part
539  // of 14496-3.
540  // The ALS conformance files feature an odd number of samples in the last
541  // frame.
542 
543  for (b = 0; b < ctx->num_blocks; b++)
544  div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];
545 
546  if (ctx->cur_frame_length != ctx->sconf.frame_length) {
547  unsigned int remaining = ctx->cur_frame_length;
548 
549  for (b = 0; b < ctx->num_blocks; b++) {
550  if (remaining <= div_blocks[b]) {
551  div_blocks[b] = remaining;
552  ctx->num_blocks = b + 1;
553  break;
554  }
555 
556  remaining -= div_blocks[b];
557  }
558  }
559 }
560 
561 
562 /** Read the block data for a constant block
563  */
564 static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
565 {
566  ALSSpecificConfig *sconf = &ctx->sconf;
567  AVCodecContext *avctx = ctx->avctx;
568  GetBitContext *gb = &ctx->gb;
569 
570  if (bd->block_length <= 0)
571  return AVERROR_INVALIDDATA;
572 
573  *bd->raw_samples = 0;
574  *bd->const_block = get_bits1(gb); // 1 = constant value, 0 = zero block (silence)
575  bd->js_blocks = get_bits1(gb);
576 
577  // skip 5 reserved bits
578  skip_bits(gb, 5);
579 
580  if (*bd->const_block) {
581  unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;
582  *bd->raw_samples = get_sbits_long(gb, const_val_bits);
583  }
584 
585  // ensure constant block decoding by reusing this field
586  *bd->const_block = 1;
587 
588  return 0;
589 }
590 
591 
592 /** Decode the block data for a constant block
593  */
594 static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
595 {
596  int smp = bd->block_length - 1;
597  int32_t val = *bd->raw_samples;
598  int32_t *dst = bd->raw_samples + 1;
599 
600  // write raw samples into buffer
601  for (; smp; smp--)
602  *dst++ = val;
603 }
604 
605 
606 /** Read the block data for a non-constant block
607  */
608 static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
609 {
610  ALSSpecificConfig *sconf = &ctx->sconf;
611  AVCodecContext *avctx = ctx->avctx;
612  GetBitContext *gb = &ctx->gb;
613  unsigned int k;
614  unsigned int s[8];
615  unsigned int sx[8];
616  unsigned int sub_blocks, log2_sub_blocks, sb_length;
617  unsigned int start = 0;
618  unsigned int opt_order;
619  int sb;
620  int32_t *quant_cof = bd->quant_cof;
621  int32_t *current_res;
622 
623 
624  // ensure variable block decoding by reusing this field
625  *bd->const_block = 0;
626 
627  *bd->opt_order = 1;
628  bd->js_blocks = get_bits1(gb);
629 
630  opt_order = *bd->opt_order;
631 
632  // determine the number of subblocks for entropy decoding
633  if (!sconf->bgmc && !sconf->sb_part) {
634  log2_sub_blocks = 0;
635  } else {
636  if (sconf->bgmc && sconf->sb_part)
637  log2_sub_blocks = get_bits(gb, 2);
638  else
639  log2_sub_blocks = 2 * get_bits1(gb);
640  }
641 
642  sub_blocks = 1 << log2_sub_blocks;
643 
644  // do not continue in case of a damaged stream since
645  // block_length must be evenly divisible by sub_blocks
646  if (bd->block_length & (sub_blocks - 1)) {
647  av_log(avctx, AV_LOG_WARNING,
648  "Block length is not evenly divisible by the number of subblocks.\n");
649  return AVERROR_INVALIDDATA;
650  }
651 
652  sb_length = bd->block_length >> log2_sub_blocks;
653 
654  if (sconf->bgmc) {
655  s[0] = get_bits(gb, 8 + (sconf->resolution > 1));
656  for (k = 1; k < sub_blocks; k++)
657  s[k] = s[k - 1] + decode_rice(gb, 2);
658 
659  for (k = 0; k < sub_blocks; k++) {
660  sx[k] = s[k] & 0x0F;
661  s [k] >>= 4;
662  }
663  } else {
664  s[0] = get_bits(gb, 4 + (sconf->resolution > 1));
665  for (k = 1; k < sub_blocks; k++)
666  s[k] = s[k - 1] + decode_rice(gb, 0);
667  }
668  for (k = 1; k < sub_blocks; k++)
669  if (s[k] > 32) {
670  av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");
671  return AVERROR_INVALIDDATA;
672  }
673 
674  if (get_bits1(gb))
675  *bd->shift_lsbs = get_bits(gb, 4) + 1;
676 
677  *bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || *bd->shift_lsbs;
678 
679 
680  if (!sconf->rlslms) {
681  if (sconf->adapt_order) {
682  int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,
683  2, sconf->max_order + 1));
684  *bd->opt_order = get_bits(gb, opt_order_length);
685  if (*bd->opt_order > sconf->max_order) {
686  *bd->opt_order = sconf->max_order;
687  av_log(avctx, AV_LOG_ERROR, "Predictor order too large.\n");
688  return AVERROR_INVALIDDATA;
689  }
690  } else {
691  *bd->opt_order = sconf->max_order;
692  }
693  if (*bd->opt_order > bd->block_length) {
694  *bd->opt_order = bd->block_length;
695  av_log(avctx, AV_LOG_ERROR, "Predictor order too large.\n");
696  return AVERROR_INVALIDDATA;
697  }
698  opt_order = *bd->opt_order;
699 
700  if (opt_order) {
701  int add_base;
702 
703  if (sconf->coef_table == 3) {
704  add_base = 0x7F;
705 
706  // read coefficient 0
707  quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];
708 
709  // read coefficient 1
710  if (opt_order > 1)
711  quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];
712 
713  // read coefficients 2 to opt_order
714  for (k = 2; k < opt_order; k++)
715  quant_cof[k] = get_bits(gb, 7);
716  } else {
717  int k_max;
718  add_base = 1;
719 
720  // read coefficient 0 to 19
721  k_max = FFMIN(opt_order, 20);
722  for (k = 0; k < k_max; k++) {
723  int rice_param = parcor_rice_table[sconf->coef_table][k][1];
724  int offset = parcor_rice_table[sconf->coef_table][k][0];
725  quant_cof[k] = decode_rice(gb, rice_param) + offset;
726  if (quant_cof[k] < -64 || quant_cof[k] > 63) {
727  av_log(avctx, AV_LOG_ERROR,
728  "quant_cof %"PRIu32" is out of range.\n",
729  quant_cof[k]);
730  return AVERROR_INVALIDDATA;
731  }
732  }
733 
734  // read coefficients 20 to 126
735  k_max = FFMIN(opt_order, 127);
736  for (; k < k_max; k++)
737  quant_cof[k] = decode_rice(gb, 2) + (k & 1);
738 
739  // read coefficients 127 to opt_order
740  for (; k < opt_order; k++)
741  quant_cof[k] = decode_rice(gb, 1);
742 
743  quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];
744 
745  if (opt_order > 1)
746  quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];
747  }
748 
749  for (k = 2; k < opt_order; k++)
750  quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);
751  }
752  }
753 
754  // read LTP gain and lag values
755  if (sconf->long_term_prediction) {
756  *bd->use_ltp = get_bits1(gb);
757 
758  if (*bd->use_ltp) {
759  int r, c;
760 
761  bd->ltp_gain[0] = decode_rice(gb, 1) << 3;
762  bd->ltp_gain[1] = decode_rice(gb, 2) << 3;
763 
764  r = get_unary(gb, 0, 3);
765  c = get_bits(gb, 2);
766  bd->ltp_gain[2] = ltp_gain_values[r][c];
767 
768  bd->ltp_gain[3] = decode_rice(gb, 2) << 3;
769  bd->ltp_gain[4] = decode_rice(gb, 1) << 3;
770 
771  *bd->ltp_lag = get_bits(gb, ctx->ltp_lag_length);
772  *bd->ltp_lag += FFMAX(4, opt_order + 1);
773  }
774  }
775 
776  // read first value and residuals in case of a random access block
777  if (bd->ra_block) {
778  if (opt_order)
779  bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
780  if (opt_order > 1)
781  bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));
782  if (opt_order > 2)
783  bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));
784 
785  start = FFMIN(opt_order, 3);
786  }
787 
788  // read all residuals
789  if (sconf->bgmc) {
790  int delta[8];
791  unsigned int k [8];
792  unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5);
793 
794  // read most significant bits
795  unsigned int high;
796  unsigned int low;
797  unsigned int value;
798 
799  ff_bgmc_decode_init(gb, &high, &low, &value);
800 
801  current_res = bd->raw_samples + start;
802 
803  for (sb = 0; sb < sub_blocks; sb++) {
804  unsigned int sb_len = sb_length - (sb ? 0 : start);
805 
806  k [sb] = s[sb] > b ? s[sb] - b : 0;
807  delta[sb] = 5 - s[sb] + k[sb];
808 
809  ff_bgmc_decode(gb, sb_len, current_res,
810  delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);
811 
812  current_res += sb_len;
813  }
814 
815  ff_bgmc_decode_end(gb);
816 
817 
818  // read least significant bits and tails
819  current_res = bd->raw_samples + start;
820 
821  for (sb = 0; sb < sub_blocks; sb++, start = 0) {
822  unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]];
823  unsigned int cur_k = k[sb];
824  unsigned int cur_s = s[sb];
825 
826  for (; start < sb_length; start++) {
827  int32_t res = *current_res;
828 
829  if (res == cur_tail_code) {
830  unsigned int max_msb = (2 + (sx[sb] > 2) + (sx[sb] > 10))
831  << (5 - delta[sb]);
832 
833  res = decode_rice(gb, cur_s);
834 
835  if (res >= 0) {
836  res += (max_msb ) << cur_k;
837  } else {
838  res -= (max_msb - 1) << cur_k;
839  }
840  } else {
841  if (res > cur_tail_code)
842  res--;
843 
844  if (res & 1)
845  res = -res;
846 
847  res >>= 1;
848 
849  if (cur_k) {
850  res <<= cur_k;
851  res |= get_bits_long(gb, cur_k);
852  }
853  }
854 
855  *current_res++ = res;
856  }
857  }
858  } else {
859  current_res = bd->raw_samples + start;
860 
861  for (sb = 0; sb < sub_blocks; sb++, start = 0)
862  for (; start < sb_length; start++)
863  *current_res++ = decode_rice(gb, s[sb]);
864  }
865 
866  if (!sconf->mc_coding || ctx->js_switch)
867  align_get_bits(gb);
868 
869  return 0;
870 }
871 
872 
873 /** Decode the block data for a non-constant block
874  */
875 static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
876 {
877  ALSSpecificConfig *sconf = &ctx->sconf;
878  unsigned int block_length = bd->block_length;
879  unsigned int smp = 0;
880  unsigned int k;
881  int opt_order = *bd->opt_order;
882  int sb;
883  int64_t y;
884  int32_t *quant_cof = bd->quant_cof;
885  int32_t *lpc_cof = bd->lpc_cof;
886  int32_t *raw_samples = bd->raw_samples;
887  int32_t *raw_samples_end = bd->raw_samples + bd->block_length;
888  int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;
889 
890  // reverse long-term prediction
891  if (*bd->use_ltp) {
892  int ltp_smp;
893 
894  for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {
895  int center = ltp_smp - *bd->ltp_lag;
896  int begin = FFMAX(0, center - 2);
897  int end = center + 3;
898  int tab = 5 - (end - begin);
899  int base;
900 
901  y = 1 << 6;
902 
903  for (base = begin; base < end; base++, tab++)
904  y += MUL64(bd->ltp_gain[tab], raw_samples[base]);
905 
906  raw_samples[ltp_smp] += y >> 7;
907  }
908  }
909 
910  // reconstruct all samples from residuals
911  if (bd->ra_block) {
912  for (smp = 0; smp < opt_order; smp++) {
913  y = 1 << 19;
914 
915  for (sb = 0; sb < smp; sb++)
916  y += MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);
917 
918  *raw_samples++ -= y >> 20;
919  parcor_to_lpc(smp, quant_cof, lpc_cof);
920  }
921  } else {
922  for (k = 0; k < opt_order; k++)
923  parcor_to_lpc(k, quant_cof, lpc_cof);
924 
925  // store previous samples in case that they have to be altered
926  if (*bd->store_prev_samples)
927  memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,
928  sizeof(*bd->prev_raw_samples) * sconf->max_order);
929 
930  // reconstruct difference signal for prediction (joint-stereo)
931  if (bd->js_blocks && bd->raw_other) {
932  int32_t *left, *right;
933 
934  if (bd->raw_other > raw_samples) { // D = R - L
935  left = raw_samples;
936  right = bd->raw_other;
937  } else { // D = R - L
938  left = bd->raw_other;
939  right = raw_samples;
940  }
941 
942  for (sb = -1; sb >= -sconf->max_order; sb--)
943  raw_samples[sb] = right[sb] - left[sb];
944  }
945 
946  // reconstruct shifted signal
947  if (*bd->shift_lsbs)
948  for (sb = -1; sb >= -sconf->max_order; sb--)
949  raw_samples[sb] >>= *bd->shift_lsbs;
950  }
951 
952  // reverse linear prediction coefficients for efficiency
953  lpc_cof = lpc_cof + opt_order;
954 
955  for (sb = 0; sb < opt_order; sb++)
956  lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];
957 
958  // reconstruct raw samples
959  raw_samples = bd->raw_samples + smp;
960  lpc_cof = lpc_cof_reversed + opt_order;
961 
962  for (; raw_samples < raw_samples_end; raw_samples++) {
963  y = 1 << 19;
964 
965  for (sb = -opt_order; sb < 0; sb++)
966  y += MUL64(lpc_cof[sb], raw_samples[sb]);
967 
968  *raw_samples -= y >> 20;
969  }
970 
971  raw_samples = bd->raw_samples;
972 
973  // restore previous samples in case that they have been altered
974  if (*bd->store_prev_samples)
975  memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,
976  sizeof(*raw_samples) * sconf->max_order);
977 
978  return 0;
979 }
980 
981 
982 /** Read the block data.
983  */
984 static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
985 {
986  int ret;
987  GetBitContext *gb = &ctx->gb;
988 
989  *bd->shift_lsbs = 0;
990  // read block type flag and read the samples accordingly
991  if (get_bits1(gb)) {
992  ret = read_var_block_data(ctx, bd);
993  } else {
994  ret = read_const_block_data(ctx, bd);
995  }
996 
997  return ret;
998 }
999 
1000 
1001 /** Decode the block data.
1002  */
1003 static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1004 {
1005  unsigned int smp;
1006  int ret = 0;
1007 
1008  // read block type flag and read the samples accordingly
1009  if (*bd->const_block)
1010  decode_const_block_data(ctx, bd);
1011  else
1012  ret = decode_var_block_data(ctx, bd); // always return 0
1013 
1014  if (ret < 0)
1015  return ret;
1016 
1017  // TODO: read RLSLMS extension data
1018 
1019  if (*bd->shift_lsbs)
1020  for (smp = 0; smp < bd->block_length; smp++)
1021  bd->raw_samples[smp] <<= *bd->shift_lsbs;
1022 
1023  return 0;
1024 }
1025 
1026 
1027 /** Read and decode block data successively.
1028  */
1029 static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)
1030 {
1031  int ret;
1032 
1033  if ((ret = read_block(ctx, bd)) < 0)
1034  return ret;
1035 
1036  return decode_block(ctx, bd);
1037 }
1038 
1039 
1040 /** Compute the number of samples left to decode for the current frame and
1041  * sets these samples to zero.
1042  */
1043 static void zero_remaining(unsigned int b, unsigned int b_max,
1044  const unsigned int *div_blocks, int32_t *buf)
1045 {
1046  unsigned int count = 0;
1047 
1048  while (b < b_max)
1049  count += div_blocks[b++];
1050 
1051  if (count)
1052  memset(buf, 0, sizeof(*buf) * count);
1053 }
1054 
1055 
1056 /** Decode blocks independently.
1057  */
1058 static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,
1059  unsigned int c, const unsigned int *div_blocks,
1060  unsigned int *js_blocks)
1061 {
1062  int ret;
1063  unsigned int b;
1064  ALSBlockData bd = { 0 };
1065 
1066  bd.ra_block = ra_frame;
1067  bd.const_block = ctx->const_block;
1068  bd.shift_lsbs = ctx->shift_lsbs;
1069  bd.opt_order = ctx->opt_order;
1070  bd.store_prev_samples = ctx->store_prev_samples;
1071  bd.use_ltp = ctx->use_ltp;
1072  bd.ltp_lag = ctx->ltp_lag;
1073  bd.ltp_gain = ctx->ltp_gain[0];
1074  bd.quant_cof = ctx->quant_cof[0];
1075  bd.lpc_cof = ctx->lpc_cof[0];
1076  bd.prev_raw_samples = ctx->prev_raw_samples;
1077  bd.raw_samples = ctx->raw_samples[c];
1078 
1079 
1080  for (b = 0; b < ctx->num_blocks; b++) {
1081  bd.block_length = div_blocks[b];
1082 
1083  if ((ret = read_decode_block(ctx, &bd)) < 0) {
1084  // damaged block, write zero for the rest of the frame
1085  zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);
1086  return ret;
1087  }
1088  bd.raw_samples += div_blocks[b];
1089  bd.ra_block = 0;
1090  }
1091 
1092  return 0;
1093 }
1094 
1095 
1096 /** Decode blocks dependently.
1097  */
1098 static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
1099  unsigned int c, const unsigned int *div_blocks,
1100  unsigned int *js_blocks)
1101 {
1102  ALSSpecificConfig *sconf = &ctx->sconf;
1103  unsigned int offset = 0;
1104  unsigned int b;
1105  int ret;
1106  ALSBlockData bd[2] = { { 0 } };
1107 
1108  bd[0].ra_block = ra_frame;
1109  bd[0].const_block = ctx->const_block;
1110  bd[0].shift_lsbs = ctx->shift_lsbs;
1111  bd[0].opt_order = ctx->opt_order;
1112  bd[0].store_prev_samples = ctx->store_prev_samples;
1113  bd[0].use_ltp = ctx->use_ltp;
1114  bd[0].ltp_lag = ctx->ltp_lag;
1115  bd[0].ltp_gain = ctx->ltp_gain[0];
1116  bd[0].quant_cof = ctx->quant_cof[0];
1117  bd[0].lpc_cof = ctx->lpc_cof[0];
1118  bd[0].prev_raw_samples = ctx->prev_raw_samples;
1119  bd[0].js_blocks = *js_blocks;
1120 
1121  bd[1].ra_block = ra_frame;
1122  bd[1].const_block = ctx->const_block;
1123  bd[1].shift_lsbs = ctx->shift_lsbs;
1124  bd[1].opt_order = ctx->opt_order;
1125  bd[1].store_prev_samples = ctx->store_prev_samples;
1126  bd[1].use_ltp = ctx->use_ltp;
1127  bd[1].ltp_lag = ctx->ltp_lag;
1128  bd[1].ltp_gain = ctx->ltp_gain[0];
1129  bd[1].quant_cof = ctx->quant_cof[0];
1130  bd[1].lpc_cof = ctx->lpc_cof[0];
1131  bd[1].prev_raw_samples = ctx->prev_raw_samples;
1132  bd[1].js_blocks = *(js_blocks + 1);
1133 
1134  // decode all blocks
1135  for (b = 0; b < ctx->num_blocks; b++) {
1136  unsigned int s;
1137 
1138  bd[0].block_length = div_blocks[b];
1139  bd[1].block_length = div_blocks[b];
1140 
1141  bd[0].raw_samples = ctx->raw_samples[c ] + offset;
1142  bd[1].raw_samples = ctx->raw_samples[c + 1] + offset;
1143 
1144  bd[0].raw_other = bd[1].raw_samples;
1145  bd[1].raw_other = bd[0].raw_samples;
1146 
1147  if ((ret = read_decode_block(ctx, &bd[0])) < 0 ||
1148  (ret = read_decode_block(ctx, &bd[1])) < 0)
1149  goto fail;
1150 
1151  // reconstruct joint-stereo blocks
1152  if (bd[0].js_blocks) {
1153  if (bd[1].js_blocks)
1154  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");
1155 
1156  for (s = 0; s < div_blocks[b]; s++)
1157  bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];
1158  } else if (bd[1].js_blocks) {
1159  for (s = 0; s < div_blocks[b]; s++)
1160  bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];
1161  }
1162 
1163  offset += div_blocks[b];
1164  bd[0].ra_block = 0;
1165  bd[1].ra_block = 0;
1166  }
1167 
1168  // store carryover raw samples,
1169  // the others channel raw samples are stored by the calling function.
1170  memmove(ctx->raw_samples[c] - sconf->max_order,
1171  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1172  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1173 
1174  return 0;
1175 fail:
1176  // damaged block, write zero for the rest of the frame
1177  zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);
1178  zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);
1179  return ret;
1180 }
1181 
1182 static inline int als_weighting(GetBitContext *gb, int k, int off)
1183 {
1184  int idx = av_clip(decode_rice(gb, k) + off,
1185  0, FF_ARRAY_ELEMS(mcc_weightings) - 1);
1186  return mcc_weightings[idx];
1187 }
1188 
1189 /** Read the channel data.
1190  */
1191 static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)
1192 {
1193  GetBitContext *gb = &ctx->gb;
1194  ALSChannelData *current = cd;
1195  unsigned int channels = ctx->avctx->channels;
1196  int entries = 0;
1197 
1198  while (entries < channels && !(current->stop_flag = get_bits1(gb))) {
1199  current->master_channel = get_bits_long(gb, av_ceil_log2(channels));
1200 
1201  if (current->master_channel >= channels) {
1202  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel.\n");
1203  return AVERROR_INVALIDDATA;
1204  }
1205 
1206  if (current->master_channel != c) {
1207  current->time_diff_flag = get_bits1(gb);
1208  current->weighting[0] = als_weighting(gb, 1, 16);
1209  current->weighting[1] = als_weighting(gb, 2, 14);
1210  current->weighting[2] = als_weighting(gb, 1, 16);
1211 
1212  if (current->time_diff_flag) {
1213  current->weighting[3] = als_weighting(gb, 1, 16);
1214  current->weighting[4] = als_weighting(gb, 1, 16);
1215  current->weighting[5] = als_weighting(gb, 1, 16);
1216 
1217  current->time_diff_sign = get_bits1(gb);
1218  current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;
1219  }
1220  }
1221 
1222  current++;
1223  entries++;
1224  }
1225 
1226  if (entries == channels) {
1227  av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data.\n");
1228  return AVERROR_INVALIDDATA;
1229  }
1230 
1231  align_get_bits(gb);
1232  return 0;
1233 }
1234 
1235 
1236 /** Recursively reverts the inter-channel correlation for a block.
1237  */
1238 static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,
1239  ALSChannelData **cd, int *reverted,
1240  unsigned int offset, int c)
1241 {
1242  ALSChannelData *ch = cd[c];
1243  unsigned int dep = 0;
1244  unsigned int channels = ctx->avctx->channels;
1245 
1246  if (reverted[c])
1247  return 0;
1248 
1249  reverted[c] = 1;
1250 
1251  while (dep < channels && !ch[dep].stop_flag) {
1252  revert_channel_correlation(ctx, bd, cd, reverted, offset,
1253  ch[dep].master_channel);
1254 
1255  dep++;
1256  }
1257 
1258  if (dep == channels) {
1259  av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation.\n");
1260  return AVERROR_INVALIDDATA;
1261  }
1262 
1263  bd->const_block = ctx->const_block + c;
1264  bd->shift_lsbs = ctx->shift_lsbs + c;
1265  bd->opt_order = ctx->opt_order + c;
1266  bd->store_prev_samples = ctx->store_prev_samples + c;
1267  bd->use_ltp = ctx->use_ltp + c;
1268  bd->ltp_lag = ctx->ltp_lag + c;
1269  bd->ltp_gain = ctx->ltp_gain[c];
1270  bd->lpc_cof = ctx->lpc_cof[c];
1271  bd->quant_cof = ctx->quant_cof[c];
1272  bd->raw_samples = ctx->raw_samples[c] + offset;
1273 
1274  for (dep = 0; !ch[dep].stop_flag; dep++) {
1275  unsigned int smp;
1276  unsigned int begin = 1;
1277  unsigned int end = bd->block_length - 1;
1278  int64_t y;
1279  int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;
1280 
1281  if (ch[dep].master_channel == c)
1282  continue;
1283 
1284  if (ch[dep].time_diff_flag) {
1285  int t = ch[dep].time_diff_index;
1286 
1287  if (ch[dep].time_diff_sign) {
1288  t = -t;
1289  begin -= t;
1290  } else {
1291  end -= t;
1292  }
1293 
1294  for (smp = begin; smp < end; smp++) {
1295  y = (1 << 6) +
1296  MUL64(ch[dep].weighting[0], master[smp - 1 ]) +
1297  MUL64(ch[dep].weighting[1], master[smp ]) +
1298  MUL64(ch[dep].weighting[2], master[smp + 1 ]) +
1299  MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +
1300  MUL64(ch[dep].weighting[4], master[smp + t]) +
1301  MUL64(ch[dep].weighting[5], master[smp + 1 + t]);
1302 
1303  bd->raw_samples[smp] += y >> 7;
1304  }
1305  } else {
1306  for (smp = begin; smp < end; smp++) {
1307  y = (1 << 6) +
1308  MUL64(ch[dep].weighting[0], master[smp - 1]) +
1309  MUL64(ch[dep].weighting[1], master[smp ]) +
1310  MUL64(ch[dep].weighting[2], master[smp + 1]);
1311 
1312  bd->raw_samples[smp] += y >> 7;
1313  }
1314  }
1315  }
1316 
1317  return 0;
1318 }
1319 
1320 
1321 /** Read the frame data.
1322  */
1323 static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
1324 {
1325  ALSSpecificConfig *sconf = &ctx->sconf;
1326  AVCodecContext *avctx = ctx->avctx;
1327  GetBitContext *gb = &ctx->gb;
1328  unsigned int div_blocks[32]; ///< block sizes.
1329  unsigned int c;
1330  unsigned int js_blocks[2];
1331  uint32_t bs_info = 0;
1332  int ret;
1333 
1334  // skip the size of the ra unit if present in the frame
1335  if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)
1336  skip_bits_long(gb, 32);
1337 
1338  if (sconf->mc_coding && sconf->joint_stereo) {
1339  ctx->js_switch = get_bits1(gb);
1340  align_get_bits(gb);
1341  }
1342 
1343  if (!sconf->mc_coding || ctx->js_switch) {
1344  int independent_bs = !sconf->joint_stereo;
1345 
1346  for (c = 0; c < avctx->channels; c++) {
1347  js_blocks[0] = 0;
1348  js_blocks[1] = 0;
1349 
1350  get_block_sizes(ctx, div_blocks, &bs_info);
1351 
1352  // if joint_stereo and block_switching is set, independent decoding
1353  // is signaled via the first bit of bs_info
1354  if (sconf->joint_stereo && sconf->block_switching)
1355  if (bs_info >> 31)
1356  independent_bs = 2;
1357 
1358  // if this is the last channel, it has to be decoded independently
1359  if (c == avctx->channels - 1)
1360  independent_bs = 1;
1361 
1362  if (independent_bs) {
1363  ret = decode_blocks_ind(ctx, ra_frame, c,
1364  div_blocks, js_blocks);
1365  if (ret < 0)
1366  return ret;
1367  independent_bs--;
1368  } else {
1369  ret = decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks);
1370  if (ret < 0)
1371  return ret;
1372 
1373  c++;
1374  }
1375 
1376  // store carryover raw samples
1377  memmove(ctx->raw_samples[c] - sconf->max_order,
1378  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1379  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1380  }
1381  } else { // multi-channel coding
1382  ALSBlockData bd = { 0 };
1383  int b, ret;
1384  int *reverted_channels = ctx->reverted_channels;
1385  unsigned int offset = 0;
1386 
1387  for (c = 0; c < avctx->channels; c++)
1388  if (ctx->chan_data[c] < ctx->chan_data_buffer) {
1389  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data.\n");
1390  return AVERROR_INVALIDDATA;
1391  }
1392 
1393  memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);
1394 
1395  bd.ra_block = ra_frame;
1396  bd.prev_raw_samples = ctx->prev_raw_samples;
1397 
1398  get_block_sizes(ctx, div_blocks, &bs_info);
1399 
1400  for (b = 0; b < ctx->num_blocks; b++) {
1401  bd.block_length = div_blocks[b];
1402  if (bd.block_length <= 0) {
1403  av_log(ctx->avctx, AV_LOG_WARNING,
1404  "Invalid block length %u in channel data!\n",
1405  bd.block_length);
1406  continue;
1407  }
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  bd.raw_other = NULL;
1421 
1422  if ((ret = read_block(ctx, &bd)) < 0)
1423  return ret;
1424  if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)
1425  return ret;
1426  }
1427 
1428  for (c = 0; c < avctx->channels; c++) {
1429  ret = revert_channel_correlation(ctx, &bd, ctx->chan_data,
1430  reverted_channels, offset, c);
1431  if (ret < 0)
1432  return ret;
1433  }
1434  for (c = 0; c < avctx->channels; c++) {
1435  bd.const_block = ctx->const_block + c;
1436  bd.shift_lsbs = ctx->shift_lsbs + c;
1437  bd.opt_order = ctx->opt_order + c;
1438  bd.store_prev_samples = ctx->store_prev_samples + c;
1439  bd.use_ltp = ctx->use_ltp + c;
1440  bd.ltp_lag = ctx->ltp_lag + c;
1441  bd.ltp_gain = ctx->ltp_gain[c];
1442  bd.lpc_cof = ctx->lpc_cof[c];
1443  bd.quant_cof = ctx->quant_cof[c];
1444  bd.raw_samples = ctx->raw_samples[c] + offset;
1445 
1446  if ((ret = decode_block(ctx, &bd)) < 0)
1447  return ret;
1448  }
1449 
1450  memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));
1451  offset += div_blocks[b];
1452  bd.ra_block = 0;
1453  }
1454 
1455  // store carryover raw samples
1456  for (c = 0; c < avctx->channels; c++)
1457  memmove(ctx->raw_samples[c] - sconf->max_order,
1458  ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
1459  sizeof(*ctx->raw_samples[c]) * sconf->max_order);
1460  }
1461 
1462  // TODO: read_diff_float_data
1463 
1464  return 0;
1465 }
1466 
1467 
1468 /** Decode an ALS frame.
1469  */
1470 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
1471  AVPacket *avpkt)
1472 {
1473  ALSDecContext *ctx = avctx->priv_data;
1474  AVFrame *frame = data;
1475  ALSSpecificConfig *sconf = &ctx->sconf;
1476  const uint8_t *buffer = avpkt->data;
1477  int buffer_size = avpkt->size;
1478  int invalid_frame, ret;
1479  unsigned int c, sample, ra_frame, bytes_read, shift;
1480 
1481  if ((ret = init_get_bits8(&ctx->gb, buffer, buffer_size)) < 0)
1482  return ret;
1483 
1484  // In the case that the distance between random access frames is set to zero
1485  // (sconf->ra_distance == 0) no frame is treated as a random access frame.
1486  // For the first frame, if prediction is used, all samples used from the
1487  // previous frame are assumed to be zero.
1488  ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);
1489 
1490  // the last frame to decode might have a different length
1491  if (sconf->samples != 0xFFFFFFFF)
1492  ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,
1493  sconf->frame_length);
1494  else
1495  ctx->cur_frame_length = sconf->frame_length;
1496 
1497  // decode the frame data
1498  if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)
1499  av_log(ctx->avctx, AV_LOG_WARNING,
1500  "Reading frame data failed. Skipping RA unit.\n");
1501 
1502  ctx->frame_id++;
1503 
1504  /* get output buffer */
1505  frame->nb_samples = ctx->cur_frame_length;
1506  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1507  return ret;
1508 
1509  // transform decoded frame into output format
1510  #define INTERLEAVE_OUTPUT(bps) \
1511  { \
1512  int##bps##_t *dest = (int##bps##_t*)frame->data[0]; \
1513  shift = bps - ctx->avctx->bits_per_raw_sample; \
1514  if (!ctx->cs_switch) { \
1515  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1516  for (c = 0; c < avctx->channels; c++) \
1517  *dest++ = ctx->raw_samples[c][sample] << shift; \
1518  } else { \
1519  for (sample = 0; sample < ctx->cur_frame_length; sample++) \
1520  for (c = 0; c < avctx->channels; c++) \
1521  *dest++ = ctx->raw_samples[sconf->chan_pos[c]][sample] << shift; \
1522  } \
1523  }
1524 
1525  if (ctx->avctx->bits_per_raw_sample <= 16) {
1526  INTERLEAVE_OUTPUT(16)
1527  } else {
1528  INTERLEAVE_OUTPUT(32)
1529  }
1530 
1531  // update CRC
1532  if (sconf->crc_enabled && (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1533  int swap = HAVE_BIGENDIAN != sconf->msb_first;
1534 
1535  if (ctx->avctx->bits_per_raw_sample == 24) {
1536  int32_t *src = (int32_t *)frame->data[0];
1537 
1538  for (sample = 0;
1539  sample < ctx->cur_frame_length * avctx->channels;
1540  sample++) {
1541  int32_t v;
1542 
1543  if (swap)
1544  v = av_bswap32(src[sample]);
1545  else
1546  v = src[sample];
1547  if (!HAVE_BIGENDIAN)
1548  v >>= 8;
1549 
1550  ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);
1551  }
1552  } else {
1553  uint8_t *crc_source;
1554 
1555  if (swap) {
1556  if (ctx->avctx->bits_per_raw_sample <= 16) {
1557  int16_t *src = (int16_t*) frame->data[0];
1558  int16_t *dest = (int16_t*) ctx->crc_buffer;
1559  for (sample = 0;
1560  sample < ctx->cur_frame_length * avctx->channels;
1561  sample++)
1562  *dest++ = av_bswap16(src[sample]);
1563  } else {
1564  ctx->bdsp.bswap_buf((uint32_t *) ctx->crc_buffer,
1565  (uint32_t *) frame->data[0],
1566  ctx->cur_frame_length * avctx->channels);
1567  }
1568  crc_source = ctx->crc_buffer;
1569  } else {
1570  crc_source = frame->data[0];
1571  }
1572 
1573  ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,
1574  ctx->cur_frame_length * avctx->channels *
1575  av_get_bytes_per_sample(avctx->sample_fmt));
1576  }
1577 
1578 
1579  // check CRC sums if this is the last frame
1580  if (ctx->cur_frame_length != sconf->frame_length &&
1581  ctx->crc_org != ctx->crc) {
1582  av_log(avctx, AV_LOG_ERROR, "CRC error.\n");
1583  if (avctx->err_recognition & AV_EF_EXPLODE)
1584  return AVERROR_INVALIDDATA;
1585  }
1586  }
1587 
1588  *got_frame_ptr = 1;
1589 
1590  bytes_read = invalid_frame ? buffer_size :
1591  (get_bits_count(&ctx->gb) + 7) >> 3;
1592 
1593  return bytes_read;
1594 }
1595 
1596 
1597 /** Uninitialize the ALS decoder.
1598  */
1599 static av_cold int decode_end(AVCodecContext *avctx)
1600 {
1601  ALSDecContext *ctx = avctx->priv_data;
1602 
1603  av_freep(&ctx->sconf.chan_pos);
1604 
1605  ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);
1606 
1607  av_freep(&ctx->const_block);
1608  av_freep(&ctx->shift_lsbs);
1609  av_freep(&ctx->opt_order);
1610  av_freep(&ctx->store_prev_samples);
1611  av_freep(&ctx->use_ltp);
1612  av_freep(&ctx->ltp_lag);
1613  av_freep(&ctx->ltp_gain);
1614  av_freep(&ctx->ltp_gain_buffer);
1615  av_freep(&ctx->quant_cof);
1616  av_freep(&ctx->lpc_cof);
1617  av_freep(&ctx->quant_cof_buffer);
1618  av_freep(&ctx->lpc_cof_buffer);
1619  av_freep(&ctx->lpc_cof_reversed_buffer);
1620  av_freep(&ctx->prev_raw_samples);
1621  av_freep(&ctx->raw_samples);
1622  av_freep(&ctx->raw_buffer);
1623  av_freep(&ctx->chan_data);
1624  av_freep(&ctx->chan_data_buffer);
1625  av_freep(&ctx->reverted_channels);
1626  av_freep(&ctx->crc_buffer);
1627 
1628  return 0;
1629 }
1630 
1631 
1632 /** Initialize the ALS decoder.
1633  */
1634 static av_cold int decode_init(AVCodecContext *avctx)
1635 {
1636  unsigned int c;
1637  unsigned int channel_size;
1638  int num_buffers, ret;
1639  ALSDecContext *ctx = avctx->priv_data;
1640  ALSSpecificConfig *sconf = &ctx->sconf;
1641  ctx->avctx = avctx;
1642 
1643  if (!avctx->extradata) {
1644  av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");
1645  return AVERROR_INVALIDDATA;
1646  }
1647 
1648  if ((ret = read_specific_config(ctx)) < 0) {
1649  av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");
1650  goto fail;
1651  }
1652 
1653  if ((ret = check_specific_config(ctx)) < 0) {
1654  goto fail;
1655  }
1656 
1657  if (sconf->bgmc) {
1658  ret = ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);
1659  if (ret < 0)
1660  goto fail;
1661  }
1662  if (sconf->floating) {
1663  avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
1664  avctx->bits_per_raw_sample = 32;
1665  } else {
1666  avctx->sample_fmt = sconf->resolution > 1
1667  ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
1668  avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;
1669  }
1670 
1671  // set maximum Rice parameter for progressive decoding based on resolution
1672  // This is not specified in 14496-3 but actually done by the reference
1673  // codec RM22 revision 2.
1674  ctx->s_max = sconf->resolution > 1 ? 31 : 15;
1675 
1676  // set lag value for long-term prediction
1677  ctx->ltp_lag_length = 8 + (avctx->sample_rate >= 96000) +
1678  (avctx->sample_rate >= 192000);
1679 
1680  // allocate quantized parcor coefficient buffer
1681  num_buffers = sconf->mc_coding ? avctx->channels : 1;
1682 
1683  ctx->quant_cof = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);
1684  ctx->lpc_cof = av_malloc(sizeof(*ctx->lpc_cof) * num_buffers);
1685  ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *
1686  num_buffers * sconf->max_order);
1687  ctx->lpc_cof_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *
1688  num_buffers * sconf->max_order);
1689  ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *
1690  sconf->max_order);
1691 
1692  if (!ctx->quant_cof || !ctx->lpc_cof ||
1693  !ctx->quant_cof_buffer || !ctx->lpc_cof_buffer ||
1694  !ctx->lpc_cof_reversed_buffer) {
1695  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1696  ret = AVERROR(ENOMEM);
1697  goto fail;
1698  }
1699 
1700  // assign quantized parcor coefficient buffers
1701  for (c = 0; c < num_buffers; c++) {
1702  ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;
1703  ctx->lpc_cof[c] = ctx->lpc_cof_buffer + c * sconf->max_order;
1704  }
1705 
1706  // allocate and assign lag and gain data buffer for ltp mode
1707  ctx->const_block = av_malloc (sizeof(*ctx->const_block) * num_buffers);
1708  ctx->shift_lsbs = av_malloc (sizeof(*ctx->shift_lsbs) * num_buffers);
1709  ctx->opt_order = av_malloc (sizeof(*ctx->opt_order) * num_buffers);
1710  ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);
1711  ctx->use_ltp = av_mallocz(sizeof(*ctx->use_ltp) * num_buffers);
1712  ctx->ltp_lag = av_malloc (sizeof(*ctx->ltp_lag) * num_buffers);
1713  ctx->ltp_gain = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);
1714  ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *
1715  num_buffers * 5);
1716 
1717  if (!ctx->const_block || !ctx->shift_lsbs ||
1718  !ctx->opt_order || !ctx->store_prev_samples ||
1719  !ctx->use_ltp || !ctx->ltp_lag ||
1720  !ctx->ltp_gain || !ctx->ltp_gain_buffer) {
1721  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1722  ret = AVERROR(ENOMEM);
1723  goto fail;
1724  }
1725 
1726  for (c = 0; c < num_buffers; c++)
1727  ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;
1728 
1729  // allocate and assign channel data buffer for mcc mode
1730  if (sconf->mc_coding) {
1731  ctx->chan_data_buffer = av_malloc(sizeof(*ctx->chan_data_buffer) *
1732  num_buffers * num_buffers);
1733  ctx->chan_data = av_malloc(sizeof(*ctx->chan_data) *
1734  num_buffers);
1735  ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *
1736  num_buffers);
1737 
1738  if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {
1739  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1740  ret = AVERROR(ENOMEM);
1741  goto fail;
1742  }
1743 
1744  for (c = 0; c < num_buffers; c++)
1745  ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;
1746  } else {
1747  ctx->chan_data = NULL;
1748  ctx->chan_data_buffer = NULL;
1749  ctx->reverted_channels = NULL;
1750  }
1751 
1752  channel_size = sconf->frame_length + sconf->max_order;
1753 
1754  ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);
1755  ctx->raw_buffer = av_mallocz(sizeof(*ctx-> raw_buffer) * avctx->channels * channel_size);
1756  ctx->raw_samples = av_malloc (sizeof(*ctx-> raw_samples) * avctx->channels);
1757 
1758  // allocate previous raw sample buffer
1759  if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {
1760  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1761  ret = AVERROR(ENOMEM);
1762  goto fail;
1763  }
1764 
1765  // assign raw samples buffers
1766  ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;
1767  for (c = 1; c < avctx->channels; c++)
1768  ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;
1769 
1770  // allocate crc buffer
1771  if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&
1772  (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL))) {
1773  ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *
1774  ctx->cur_frame_length *
1775  avctx->channels *
1776  av_get_bytes_per_sample(avctx->sample_fmt));
1777  if (!ctx->crc_buffer) {
1778  av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
1779  ret = AVERROR(ENOMEM);
1780  goto fail;
1781  }
1782  }
1783 
1784  ff_bswapdsp_init(&ctx->bdsp);
1785 
1786  return 0;
1787 
1788 fail:
1789  decode_end(avctx);
1790  return ret;
1791 }
1792 
1793 
1794 /** Flush (reset) the frame ID after seeking.
1795  */
1796 static av_cold void flush(AVCodecContext *avctx)
1797 {
1798  ALSDecContext *ctx = avctx->priv_data;
1799 
1800  ctx->frame_id = 0;
1801 }
1802 
1803 
1804 AVCodec ff_als_decoder = {
1805  .name = "als",
1806  .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),
1807  .type = AVMEDIA_TYPE_AUDIO,
1808  .id = AV_CODEC_ID_MP4ALS,
1809  .priv_data_size = sizeof(ALSDecContext),
1810  .init = decode_init,
1811  .close = decode_end,
1812  .decode = decode_frame,
1813  .flush = flush,
1814  .capabilities = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
1815 };
Generated on Sun Mar 8 2015 02:34:47 for FFmpeg by   doxygen 1.8.2