alac.c
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1 /*
2  * ALAC (Apple Lossless Audio Codec) decoder
3  * Copyright (c) 2005 David Hammerton
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
49 #include "avcodec.h"
50 #include "get_bits.h"
51 #include "bytestream.h"
52 #include "internal.h"
53 #include "unary.h"
54 #include "mathops.h"
55 #include "alac_data.h"
56 
57 #define ALAC_EXTRADATA_SIZE 36
58 
59 typedef struct {
63  int channels;
64 
65  int32_t *predict_error_buffer[2];
66  int32_t *output_samples_buffer[2];
67  int32_t *extra_bits_buffer[2];
68 
74 
75  int extra_bits;
76  int nb_samples;
77 } ALACContext;
78 
79 static inline unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
80 {
81  unsigned int x = get_unary_0_9(gb);
82 
83  if (x > 8) { /* RICE THRESHOLD */
84  /* use alternative encoding */
85  x = get_bits_long(gb, bps);
86  } else if (k != 1) {
87  int extrabits = show_bits(gb, k);
88 
89  /* multiply x by 2^k - 1, as part of their strange algorithm */
90  x = (x << k) - x;
91 
92  if (extrabits > 1) {
93  x += extrabits - 1;
94  skip_bits(gb, k);
95  } else
96  skip_bits(gb, k - 1);
97  }
98  return x;
99 }
100 
102  int nb_samples, int bps, int rice_history_mult)
103 {
104  int i;
105  unsigned int history = alac->rice_initial_history;
106  int sign_modifier = 0;
107 
108  for (i = 0; i < nb_samples; i++) {
109  int k;
110  unsigned int x;
111 
112  /* calculate rice param and decode next value */
113  k = av_log2((history >> 9) + 3);
114  k = FFMIN(k, alac->rice_limit);
115  x = decode_scalar(&alac->gb, k, bps);
116  x += sign_modifier;
117  sign_modifier = 0;
118  output_buffer[i] = (x >> 1) ^ -(x & 1);
119 
120  /* update the history */
121  if (x > 0xffff)
122  history = 0xffff;
123  else
124  history += x * rice_history_mult -
125  ((history * rice_history_mult) >> 9);
126 
127  /* special case: there may be compressed blocks of 0 */
128  if ((history < 128) && (i + 1 < nb_samples)) {
129  int block_size;
130 
131  /* calculate rice param and decode block size */
132  k = 7 - av_log2(history) + ((history + 16) >> 6);
133  k = FFMIN(k, alac->rice_limit);
134  block_size = decode_scalar(&alac->gb, k, 16);
135 
136  if (block_size > 0) {
137  if (block_size >= nb_samples - i) {
138  av_log(alac->avctx, AV_LOG_ERROR,
139  "invalid zero block size of %d %d %d\n", block_size,
140  nb_samples, i);
141  block_size = nb_samples - i - 1;
142  }
143  memset(&output_buffer[i + 1], 0,
144  block_size * sizeof(*output_buffer));
145  i += block_size;
146  }
147  if (block_size <= 0xffff)
148  sign_modifier = 1;
149  history = 0;
150  }
151  }
152 }
153 
154 static inline int sign_only(int v)
155 {
156  return v ? FFSIGN(v) : 0;
157 }
158 
159 static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
160  int nb_samples, int bps, int16_t *lpc_coefs,
161  int lpc_order, int lpc_quant)
162 {
163  int i;
164  int32_t *pred = buffer_out;
165 
166  /* first sample always copies */
167  *buffer_out = *error_buffer;
168 
169  if (nb_samples <= 1)
170  return;
171 
172  if (!lpc_order) {
173  memcpy(&buffer_out[1], &error_buffer[1],
174  (nb_samples - 1) * sizeof(*buffer_out));
175  return;
176  }
177 
178  if (lpc_order == 31) {
179  /* simple 1st-order prediction */
180  for (i = 1; i < nb_samples; i++) {
181  buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
182  bps);
183  }
184  return;
185  }
186 
187  /* read warm-up samples */
188  for (i = 1; i <= lpc_order; i++)
189  buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], bps);
190 
191  /* NOTE: 4 and 8 are very common cases that could be optimized. */
192 
193  for (; i < nb_samples; i++) {
194  int j;
195  int val = 0;
196  int error_val = error_buffer[i];
197  int error_sign;
198  int d = *pred++;
199 
200  /* LPC prediction */
201  for (j = 0; j < lpc_order; j++)
202  val += (pred[j] - d) * lpc_coefs[j];
203  val = (val + (1 << (lpc_quant - 1))) >> lpc_quant;
204  val += d + error_val;
205  buffer_out[i] = sign_extend(val, bps);
206 
207  /* adapt LPC coefficients */
208  error_sign = sign_only(error_val);
209  if (error_sign) {
210  for (j = 0; j < lpc_order && error_val * error_sign > 0; j++) {
211  int sign;
212  val = d - pred[j];
213  sign = sign_only(val) * error_sign;
214  lpc_coefs[j] -= sign;
215  val *= sign;
216  error_val -= (val >> lpc_quant) * (j + 1);
217  }
218  }
219  }
220 }
221 
223  int decorr_shift, int decorr_left_weight)
224 {
225  int i;
226 
227  for (i = 0; i < nb_samples; i++) {
228  int32_t a, b;
229 
230  a = buffer[0][i];
231  b = buffer[1][i];
232 
233  a -= (b * decorr_left_weight) >> decorr_shift;
234  b += a;
235 
236  buffer[0][i] = b;
237  buffer[1][i] = a;
238  }
239 }
240 
241 static void append_extra_bits(int32_t *buffer[2], int32_t *extra_bits_buffer[2],
242  int extra_bits, int channels, int nb_samples)
243 {
244  int i, ch;
245 
246  for (ch = 0; ch < channels; ch++)
247  for (i = 0; i < nb_samples; i++)
248  buffer[ch][i] = (buffer[ch][i] << extra_bits) | extra_bits_buffer[ch][i];
249 }
250 
251 static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
252  int channels)
253 {
254  ALACContext *alac = avctx->priv_data;
255  int has_size, bps, is_compressed, decorr_shift, decorr_left_weight, ret;
256  uint32_t output_samples;
257  int i, ch;
258 
259  skip_bits(&alac->gb, 4); /* element instance tag */
260  skip_bits(&alac->gb, 12); /* unused header bits */
261 
262  /* the number of output samples is stored in the frame */
263  has_size = get_bits1(&alac->gb);
264 
265  alac->extra_bits = get_bits(&alac->gb, 2) << 3;
266  bps = alac->sample_size - alac->extra_bits + channels - 1;
267  if (bps > 32) {
268  av_log(avctx, AV_LOG_ERROR, "bps is unsupported: %d\n", bps);
269  return AVERROR_PATCHWELCOME;
270  }
271 
272  /* whether the frame is compressed */
273  is_compressed = !get_bits1(&alac->gb);
274 
275  if (has_size)
276  output_samples = get_bits_long(&alac->gb, 32);
277  else
278  output_samples = alac->max_samples_per_frame;
279  if (!output_samples || output_samples > alac->max_samples_per_frame) {
280  av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %d\n",
281  output_samples);
282  return AVERROR_INVALIDDATA;
283  }
284  if (!alac->nb_samples) {
285  /* get output buffer */
286  alac->frame.nb_samples = output_samples;
287  if ((ret = ff_get_buffer(avctx, &alac->frame)) < 0) {
288  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
289  return ret;
290  }
291  } else if (output_samples != alac->nb_samples) {
292  av_log(avctx, AV_LOG_ERROR, "sample count mismatch: %u != %d\n",
293  output_samples, alac->nb_samples);
294  return AVERROR_INVALIDDATA;
295  }
296  alac->nb_samples = output_samples;
297  if (alac->sample_size > 16) {
298  for (ch = 0; ch < channels; ch++)
299  alac->output_samples_buffer[ch] = (int32_t *)alac->frame.extended_data[ch_index + ch];
300  }
301 
302  if (is_compressed) {
303  int16_t lpc_coefs[2][32];
304  int lpc_order[2];
305  int prediction_type[2];
306  int lpc_quant[2];
307  int rice_history_mult[2];
308 
309  decorr_shift = get_bits(&alac->gb, 8);
310  decorr_left_weight = get_bits(&alac->gb, 8);
311 
312  for (ch = 0; ch < channels; ch++) {
313  prediction_type[ch] = get_bits(&alac->gb, 4);
314  lpc_quant[ch] = get_bits(&alac->gb, 4);
315  rice_history_mult[ch] = get_bits(&alac->gb, 3);
316  lpc_order[ch] = get_bits(&alac->gb, 5);
317 
318  if (lpc_order[ch] >= alac->max_samples_per_frame)
319  return AVERROR_INVALIDDATA;
320 
321  /* read the predictor table */
322  for (i = lpc_order[ch] - 1; i >= 0; i--)
323  lpc_coefs[ch][i] = get_sbits(&alac->gb, 16);
324  }
325 
326  if (alac->extra_bits) {
327  for (i = 0; i < alac->nb_samples; i++) {
328  for (ch = 0; ch < channels; ch++)
329  alac->extra_bits_buffer[ch][i] = get_bits(&alac->gb, alac->extra_bits);
330  }
331  }
332  for (ch = 0; ch < channels; ch++) {
333  rice_decompress(alac, alac->predict_error_buffer[ch],
334  alac->nb_samples, bps,
335  rice_history_mult[ch] * alac->rice_history_mult / 4);
336 
337  /* adaptive FIR filter */
338  if (prediction_type[ch] == 15) {
339  /* Prediction type 15 runs the adaptive FIR twice.
340  * The first pass uses the special-case coef_num = 31, while
341  * the second pass uses the coefs from the bitstream.
342  *
343  * However, this prediction type is not currently used by the
344  * reference encoder.
345  */
347  alac->predict_error_buffer[ch],
348  alac->nb_samples, bps, NULL, 31, 0);
349  } else if (prediction_type[ch] > 0) {
350  av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
351  prediction_type[ch]);
352  }
354  alac->output_samples_buffer[ch], alac->nb_samples,
355  bps, lpc_coefs[ch], lpc_order[ch], lpc_quant[ch]);
356  }
357  } else {
358  /* not compressed, easy case */
359  for (i = 0; i < alac->nb_samples; i++) {
360  for (ch = 0; ch < channels; ch++) {
361  alac->output_samples_buffer[ch][i] =
362  get_sbits_long(&alac->gb, alac->sample_size);
363  }
364  }
365  alac->extra_bits = 0;
366  decorr_shift = 0;
367  decorr_left_weight = 0;
368  }
369 
370  if (channels == 2 && decorr_left_weight) {
372  decorr_shift, decorr_left_weight);
373  }
374 
375  if (alac->extra_bits) {
377  alac->extra_bits, channels, alac->nb_samples);
378  }
379 
380  switch(alac->sample_size) {
381  case 16: {
382  for (ch = 0; ch < channels; ch++) {
383  int16_t *outbuffer = (int16_t *)alac->frame.extended_data[ch_index + ch];
384  for (i = 0; i < alac->nb_samples; i++)
385  *outbuffer++ = alac->output_samples_buffer[ch][i];
386  }}
387  break;
388  case 24: {
389  for (ch = 0; ch < channels; ch++) {
390  for (i = 0; i < alac->nb_samples; i++)
391  alac->output_samples_buffer[ch][i] <<= 8;
392  }}
393  break;
394  }
395 
396  return 0;
397 }
398 
399 static int alac_decode_frame(AVCodecContext *avctx, void *data,
400  int *got_frame_ptr, AVPacket *avpkt)
401 {
402  ALACContext *alac = avctx->priv_data;
403  enum AlacRawDataBlockType element;
404  int channels;
405  int ch, ret, got_end;
406 
407  init_get_bits(&alac->gb, avpkt->data, avpkt->size * 8);
408 
409  got_end = 0;
410  alac->nb_samples = 0;
411  ch = 0;
412  while (get_bits_left(&alac->gb) >= 3) {
413  element = get_bits(&alac->gb, 3);
414  if (element == TYPE_END) {
415  got_end = 1;
416  break;
417  }
418  if (element > TYPE_CPE && element != TYPE_LFE) {
419  av_log(avctx, AV_LOG_ERROR, "syntax element unsupported: %d", element);
420  return AVERROR_PATCHWELCOME;
421  }
422 
423  channels = (element == TYPE_CPE) ? 2 : 1;
424  if (ch + channels > alac->channels ||
425  ff_alac_channel_layout_offsets[alac->channels - 1][ch] + channels > alac->channels) {
426  av_log(avctx, AV_LOG_ERROR, "invalid element channel count\n");
427  return AVERROR_INVALIDDATA;
428  }
429 
430  ret = decode_element(avctx, data,
432  channels);
433  if (ret < 0 && get_bits_left(&alac->gb))
434  return ret;
435 
436  ch += channels;
437  }
438  if (!got_end) {
439  av_log(avctx, AV_LOG_ERROR, "no end tag found. incomplete packet.\n");
440  return AVERROR_INVALIDDATA;
441  }
442 
443  if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8) {
444  av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
445  avpkt->size * 8 - get_bits_count(&alac->gb));
446  }
447 
448  *got_frame_ptr = 1;
449  *(AVFrame *)data = alac->frame;
450 
451  return avpkt->size;
452 }
453 
455 {
456  ALACContext *alac = avctx->priv_data;
457 
458  int ch;
459  for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
460  av_freep(&alac->predict_error_buffer[ch]);
461  if (alac->sample_size == 16)
462  av_freep(&alac->output_samples_buffer[ch]);
463  av_freep(&alac->extra_bits_buffer[ch]);
464  }
465 
466  return 0;
467 }
468 
469 static int allocate_buffers(ALACContext *alac)
470 {
471  int ch;
472  int buf_size = alac->max_samples_per_frame * sizeof(int32_t);
473 
474  for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
476  buf_size, buf_alloc_fail);
477 
478  if (alac->sample_size == 16) {
480  buf_size, buf_alloc_fail);
481  }
482 
483  FF_ALLOC_OR_GOTO(alac->avctx, alac->extra_bits_buffer[ch],
484  buf_size, buf_alloc_fail);
485  }
486  return 0;
487 buf_alloc_fail:
488  alac_decode_close(alac->avctx);
489  return AVERROR(ENOMEM);
490 }
491 
492 static int alac_set_info(ALACContext *alac)
493 {
494  GetByteContext gb;
495 
496  bytestream2_init(&gb, alac->avctx->extradata,
497  alac->avctx->extradata_size);
498 
499  bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4
500 
501  alac->max_samples_per_frame = bytestream2_get_be32u(&gb);
502  if (!alac->max_samples_per_frame ||
503  alac->max_samples_per_frame > INT_MAX / sizeof(int32_t)) {
504  av_log(alac->avctx, AV_LOG_ERROR, "max samples per frame invalid: %u\n",
505  alac->max_samples_per_frame);
506  return AVERROR_INVALIDDATA;
507  }
508  bytestream2_skipu(&gb, 1); // compatible version
509  alac->sample_size = bytestream2_get_byteu(&gb);
510  alac->rice_history_mult = bytestream2_get_byteu(&gb);
511  alac->rice_initial_history = bytestream2_get_byteu(&gb);
512  alac->rice_limit = bytestream2_get_byteu(&gb);
513  alac->channels = bytestream2_get_byteu(&gb);
514  bytestream2_get_be16u(&gb); // maxRun
515  bytestream2_get_be32u(&gb); // max coded frame size
516  bytestream2_get_be32u(&gb); // average bitrate
517  bytestream2_get_be32u(&gb); // samplerate
518 
519  return 0;
520 }
521 
523 {
524  int ret;
525  ALACContext *alac = avctx->priv_data;
526  alac->avctx = avctx;
527 
528  /* initialize from the extradata */
530  av_log(avctx, AV_LOG_ERROR, "alac: extradata is too small\n");
531  return AVERROR_INVALIDDATA;
532  }
533  if (alac_set_info(alac)) {
534  av_log(avctx, AV_LOG_ERROR, "alac: set_info failed\n");
535  return -1;
536  }
537 
538  switch (alac->sample_size) {
539  case 16: avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
540  break;
541  case 24:
542  case 32: avctx->sample_fmt = AV_SAMPLE_FMT_S32P;
543  break;
544  default: av_log_ask_for_sample(avctx, "Sample depth %d is not supported.\n",
545  alac->sample_size);
546  return AVERROR_PATCHWELCOME;
547  }
548  avctx->bits_per_raw_sample = alac->sample_size;
549 
550  if (alac->channels < 1) {
551  av_log(avctx, AV_LOG_WARNING, "Invalid channel count\n");
552  alac->channels = avctx->channels;
553  } else {
554  if (alac->channels > ALAC_MAX_CHANNELS)
555  alac->channels = avctx->channels;
556  else
557  avctx->channels = alac->channels;
558  }
559  if (avctx->channels > ALAC_MAX_CHANNELS) {
560  av_log(avctx, AV_LOG_ERROR, "Unsupported channel count: %d\n",
561  avctx->channels);
562  return AVERROR_PATCHWELCOME;
563  }
564  avctx->channel_layout = ff_alac_channel_layouts[alac->channels - 1];
565 
566  if ((ret = allocate_buffers(alac)) < 0) {
567  av_log(avctx, AV_LOG_ERROR, "Error allocating buffers\n");
568  return ret;
569  }
570 
572  avctx->coded_frame = &alac->frame;
573 
574  return 0;
575 }
576 
578  .name = "alac",
579  .type = AVMEDIA_TYPE_AUDIO,
580  .id = AV_CODEC_ID_ALAC,
581  .priv_data_size = sizeof(ALACContext),
585  .capabilities = CODEC_CAP_DR1,
586  .long_name = NULL_IF_CONFIG_SMALL("ALAC (Apple Lossless Audio Codec)"),
587 };
#define extra_bits(eb)
Definition: intrax8.c:151
int nb_samples
number of samples in the current frame
Definition: alac.c:76
This structure describes decoded (raw) audio or video data.
Definition: avcodec.h:989
#define ALAC_EXTRADATA_SIZE
Definition: alac.c:57
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:237
Definition: aac.h:57
AVFrame * coded_frame
the picture in the bitstream
Definition: avcodec.h:2725
Definition: aac.h:51
int size
Definition: avcodec.h:916
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:130
int bits_per_raw_sample
Bits per sample/pixel of internal libavcodec pixel/sample format.
Definition: avcodec.h:2711
int32_t * extra_bits_buffer[2]
Definition: alac.c:67
AVCodec.
Definition: avcodec.h:2960
static int get_sbits(GetBitContext *s, int n)
Definition: get_bits.h:223
static int get_sbits_long(GetBitContext *s, int n)
Read 0-32 bits as a signed integer.
Definition: get_bits.h:337
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:151
int32_t * predict_error_buffer[2]
Definition: alac.c:65
static int get_unary_0_9(GetBitContext *gb)
Definition: unary.h:51
static int decode(MimicContext *ctx, int quality, int num_coeffs, int is_iframe)
Definition: mimic.c:228
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:2112
uint8_t
uint8_t rice_initial_history
Definition: alac.c:72
Definition: aac.h:53
static av_cold int alac_decode_close(AVCodecContext *avctx)
Definition: alac.c:454
#define b
Definition: input.c:52
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1454
AVFrame frame
Definition: alac.c:61
const char data[16]
Definition: mxf.c:66
uint8_t * data
Definition: avcodec.h:915
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:192
static av_always_inline void bytestream2_skipu(GetByteContext *g, unsigned int size)
Definition: bytestream.h:165
bitstream reader API header.
int32_t * output_samples_buffer[2]
Definition: alac.c:66
static int alac_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: alac.c:399
signed 32 bits, planar
Definition: samplefmt.h:59
int extra_bits
number of extra bits beyond 16-bit
Definition: alac.c:75
static int init(AVCodecParserContext *s)
Definition: h264_parser.c:335
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:547
static void append_extra_bits(int32_t *buffer[2], int32_t *extra_bits_buffer[2], int extra_bits, int channels, int nb_samples)
Definition: alac.c:241
static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out, int nb_samples, int bps, int16_t *lpc_coefs, int lpc_order, int lpc_quant)
Definition: alac.c:159
void av_log_ask_for_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message asking for a sample.
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:88
static int sign_only(int v)
Definition: alac.c:154
AlacRawDataBlockType
Definition: alac_data.h:26
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:146
const char * name
Name of the codec implementation.
Definition: avcodec.h:2967
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2165
#define ALAC_MAX_CHANNELS
Definition: alac_data.h:38
uint32_t max_samples_per_frame
Definition: alac.c:69
static void output_buffer(int16_t **samples, int nchan, int blocksize, int32_t **buffer)
Definition: shorten.c:268
static void decorrelate_stereo(int32_t *buffer[2], int nb_samples, int decorr_shift, int decorr_left_weight)
Definition: alac.c:222
audio channel layout utility functions
GetBitContext gb
Definition: alac.c:62
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame)
Get a buffer for a frame.
Definition: utils.c:464
int32_t
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:251
static int alac_set_info(ALACContext *alac)
Definition: alac.c:492
static char buffer[20]
Definition: seek-test.c:31
uint8_t rice_history_mult
Definition: alac.c:71
const uint64_t ff_alac_channel_layouts[ALAC_MAX_CHANNELS+1]
Definition: alac_data.c:35
static const float pred[4]
Definition: siprdata.h:259
NULL
Definition: eval.c:52
external API header
main external API structure.
Definition: avcodec.h:1339
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:326
out nb_samples
int extradata_size
Definition: avcodec.h:1455
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:268
void avcodec_get_frame_defaults(AVFrame *frame)
Set the fields of the given AVFrame to default values.
Definition: utils.c:604
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:260
static void rice_decompress(ALACContext *alac, int32_t *output_buffer, int nb_samples, int bps, int rice_history_mult)
Definition: alac.c:101
static unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
Definition: alac.c:79
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:372
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:301
const uint8_t ff_alac_channel_layout_offsets[ALAC_MAX_CHANNELS][ALAC_MAX_CHANNELS]
Definition: alac_data.c:24
static av_const int sign_extend(int val, unsigned bits)
Definition: mathops.h:123
uint8_t sample_size
Definition: alac.c:70
int channels
Definition: alac.c:63
AVCodec ff_alac_decoder
Definition: alac.c:577
common internal api header.
static av_cold int alac_decode_init(AVCodecContext *avctx)
Definition: alac.c:522
#define FF_ALLOC_OR_GOTO(ctx, p, size, label)
Definition: internal.h:60
uint8_t rice_limit
Definition: alac.c:73
unsigned bps
Definition: movenc.c:803
void * priv_data
Definition: avcodec.h:1382
static int allocate_buffers(ALACContext *alac)
Definition: alac.c:469
int channels
number of audio channels
Definition: avcodec.h:2105
#define av_log2
Definition: intmath.h:85
AVCodecContext * avctx
Definition: alac.c:60
signed 16 bits, planar
Definition: samplefmt.h:58
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: avcodec.h:1028
This structure stores compressed data.
Definition: avcodec.h:898
int nb_samples
number of audio samples (per channel) described by this frame
Definition: avcodec.h:1042
for(j=16;j >0;--j)
static int decode_element(AVCodecContext *avctx, void *data, int ch_index, int channels)
Definition: alac.c:251