Libav
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 {
62  int channels;
63 
64  int32_t *predict_error_buffer[2];
65  int32_t *output_samples_buffer[2];
66  int32_t *extra_bits_buffer[2];
67 
73 
74  int extra_bits;
75  int nb_samples;
76 } ALACContext;
77 
78 static inline unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
79 {
80  unsigned int x = get_unary_0_9(gb);
81 
82  if (x > 8) { /* RICE THRESHOLD */
83  /* use alternative encoding */
84  x = get_bits_long(gb, bps);
85  } else if (k != 1) {
86  int extrabits = show_bits(gb, k);
87 
88  /* multiply x by 2^k - 1, as part of their strange algorithm */
89  x = (x << k) - x;
90 
91  if (extrabits > 1) {
92  x += extrabits - 1;
93  skip_bits(gb, k);
94  } else
95  skip_bits(gb, k - 1);
96  }
97  return x;
98 }
99 
101  int nb_samples, int bps, int rice_history_mult)
102 {
103  int i;
104  unsigned int history = alac->rice_initial_history;
105  int sign_modifier = 0;
106 
107  for (i = 0; i < nb_samples; i++) {
108  int k;
109  unsigned int x;
110 
111  /* calculate rice param and decode next value */
112  k = av_log2((history >> 9) + 3);
113  k = FFMIN(k, alac->rice_limit);
114  x = decode_scalar(&alac->gb, k, bps);
115  x += sign_modifier;
116  sign_modifier = 0;
117  output_buffer[i] = (x >> 1) ^ -(x & 1);
118 
119  /* update the history */
120  if (x > 0xffff)
121  history = 0xffff;
122  else
123  history += x * rice_history_mult -
124  ((history * rice_history_mult) >> 9);
125 
126  /* special case: there may be compressed blocks of 0 */
127  if ((history < 128) && (i + 1 < nb_samples)) {
128  int block_size;
129 
130  /* calculate rice param and decode block size */
131  k = 7 - av_log2(history) + ((history + 16) >> 6);
132  k = FFMIN(k, alac->rice_limit);
133  block_size = decode_scalar(&alac->gb, k, 16);
134 
135  if (block_size > 0) {
136  if (block_size >= nb_samples - i) {
137  av_log(alac->avctx, AV_LOG_ERROR,
138  "invalid zero block size of %d %d %d\n", block_size,
139  nb_samples, i);
140  block_size = nb_samples - i - 1;
141  }
142  memset(&output_buffer[i + 1], 0,
143  block_size * sizeof(*output_buffer));
144  i += block_size;
145  }
146  if (block_size <= 0xffff)
147  sign_modifier = 1;
148  history = 0;
149  }
150  }
151 }
152 
153 static inline int sign_only(int v)
154 {
155  return v ? FFSIGN(v) : 0;
156 }
157 
158 static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
159  int nb_samples, int bps, int16_t *lpc_coefs,
160  int lpc_order, int lpc_quant)
161 {
162  int i;
163  int32_t *pred = buffer_out;
164 
165  /* first sample always copies */
166  *buffer_out = *error_buffer;
167 
168  if (nb_samples <= 1)
169  return;
170 
171  if (!lpc_order) {
172  memcpy(&buffer_out[1], &error_buffer[1],
173  (nb_samples - 1) * sizeof(*buffer_out));
174  return;
175  }
176 
177  if (lpc_order == 31) {
178  /* simple 1st-order prediction */
179  for (i = 1; i < nb_samples; i++) {
180  buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
181  bps);
182  }
183  return;
184  }
185 
186  /* read warm-up samples */
187  for (i = 1; i <= lpc_order; i++)
188  buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], bps);
189 
190  /* NOTE: 4 and 8 are very common cases that could be optimized. */
191 
192  for (; i < nb_samples; i++) {
193  int j;
194  int val = 0;
195  int error_val = error_buffer[i];
196  int error_sign;
197  int d = *pred++;
198 
199  /* LPC prediction */
200  for (j = 0; j < lpc_order; j++)
201  val += (pred[j] - d) * lpc_coefs[j];
202  val = (val + (1 << (lpc_quant - 1))) >> lpc_quant;
203  val += d + error_val;
204  buffer_out[i] = sign_extend(val, bps);
205 
206  /* adapt LPC coefficients */
207  error_sign = sign_only(error_val);
208  if (error_sign) {
209  for (j = 0; j < lpc_order && error_val * error_sign > 0; j++) {
210  int sign;
211  val = d - pred[j];
212  sign = sign_only(val) * error_sign;
213  lpc_coefs[j] -= sign;
214  val *= sign;
215  error_val -= (val >> lpc_quant) * (j + 1);
216  }
217  }
218  }
219 }
220 
221 static void decorrelate_stereo(int32_t *buffer[2], int nb_samples,
222  int decorr_shift, int decorr_left_weight)
223 {
224  int i;
225 
226  for (i = 0; i < nb_samples; i++) {
227  int32_t a, b;
228 
229  a = buffer[0][i];
230  b = buffer[1][i];
231 
232  a -= (b * decorr_left_weight) >> decorr_shift;
233  b += a;
234 
235  buffer[0][i] = b;
236  buffer[1][i] = a;
237  }
238 }
239 
240 static void append_extra_bits(int32_t *buffer[2], int32_t *extra_bits_buffer[2],
241  int extra_bits, int channels, int nb_samples)
242 {
243  int i, ch;
244 
245  for (ch = 0; ch < channels; ch++)
246  for (i = 0; i < nb_samples; i++)
247  buffer[ch][i] = (buffer[ch][i] << extra_bits) | extra_bits_buffer[ch][i];
248 }
249 
250 static int decode_element(AVCodecContext *avctx, AVFrame *frame, int ch_index,
251  int channels)
252 {
253  ALACContext *alac = avctx->priv_data;
254  int has_size, bps, is_compressed, decorr_shift, decorr_left_weight, ret;
255  uint32_t output_samples;
256  int i, ch;
257 
258  skip_bits(&alac->gb, 4); /* element instance tag */
259  skip_bits(&alac->gb, 12); /* unused header bits */
260 
261  /* the number of output samples is stored in the frame */
262  has_size = get_bits1(&alac->gb);
263 
264  alac->extra_bits = get_bits(&alac->gb, 2) << 3;
265  bps = alac->sample_size - alac->extra_bits + channels - 1;
266  if (bps > 32) {
267  av_log(avctx, AV_LOG_ERROR, "bps is unsupported: %d\n", bps);
268  return AVERROR_PATCHWELCOME;
269  }
270 
271  /* whether the frame is compressed */
272  is_compressed = !get_bits1(&alac->gb);
273 
274  if (has_size)
275  output_samples = get_bits_long(&alac->gb, 32);
276  else
277  output_samples = alac->max_samples_per_frame;
278  if (!output_samples || output_samples > alac->max_samples_per_frame) {
279  av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %d\n",
280  output_samples);
281  return AVERROR_INVALIDDATA;
282  }
283  if (!alac->nb_samples) {
284  /* get output buffer */
285  frame->nb_samples = output_samples;
286  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
287  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
288  return ret;
289  }
290  } else if (output_samples != alac->nb_samples) {
291  av_log(avctx, AV_LOG_ERROR, "sample count mismatch: %u != %d\n",
292  output_samples, alac->nb_samples);
293  return AVERROR_INVALIDDATA;
294  }
295  alac->nb_samples = output_samples;
296  if (alac->sample_size > 16) {
297  for (ch = 0; ch < channels; ch++)
298  alac->output_samples_buffer[ch] = (int32_t *)frame->extended_data[ch_index + ch];
299  }
300 
301  if (is_compressed) {
302  int16_t lpc_coefs[2][32];
303  int lpc_order[2];
304  int prediction_type[2];
305  int lpc_quant[2];
306  int rice_history_mult[2];
307 
308  if (!alac->rice_limit) {
310  "Compression with rice limit 0");
311  return AVERROR(ENOSYS);
312  }
313 
314  decorr_shift = get_bits(&alac->gb, 8);
315  decorr_left_weight = get_bits(&alac->gb, 8);
316 
317  for (ch = 0; ch < channels; ch++) {
318  prediction_type[ch] = get_bits(&alac->gb, 4);
319  lpc_quant[ch] = get_bits(&alac->gb, 4);
320  rice_history_mult[ch] = get_bits(&alac->gb, 3);
321  lpc_order[ch] = get_bits(&alac->gb, 5);
322 
323  if (lpc_order[ch] >= alac->max_samples_per_frame)
324  return AVERROR_INVALIDDATA;
325 
326  /* read the predictor table */
327  for (i = lpc_order[ch] - 1; i >= 0; i--)
328  lpc_coefs[ch][i] = get_sbits(&alac->gb, 16);
329  }
330 
331  if (alac->extra_bits) {
332  for (i = 0; i < alac->nb_samples; i++) {
333  for (ch = 0; ch < channels; ch++)
334  alac->extra_bits_buffer[ch][i] = get_bits(&alac->gb, alac->extra_bits);
335  }
336  }
337  for (ch = 0; ch < channels; ch++) {
338  rice_decompress(alac, alac->predict_error_buffer[ch],
339  alac->nb_samples, bps,
340  rice_history_mult[ch] * alac->rice_history_mult / 4);
341 
342  /* adaptive FIR filter */
343  if (prediction_type[ch] == 15) {
344  /* Prediction type 15 runs the adaptive FIR twice.
345  * The first pass uses the special-case coef_num = 31, while
346  * the second pass uses the coefs from the bitstream.
347  *
348  * However, this prediction type is not currently used by the
349  * reference encoder.
350  */
352  alac->predict_error_buffer[ch],
353  alac->nb_samples, bps, NULL, 31, 0);
354  } else if (prediction_type[ch] > 0) {
355  av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
356  prediction_type[ch]);
357  }
359  alac->output_samples_buffer[ch], alac->nb_samples,
360  bps, lpc_coefs[ch], lpc_order[ch], lpc_quant[ch]);
361  }
362  } else {
363  /* not compressed, easy case */
364  for (i = 0; i < alac->nb_samples; i++) {
365  for (ch = 0; ch < channels; ch++) {
366  alac->output_samples_buffer[ch][i] =
367  get_sbits_long(&alac->gb, alac->sample_size);
368  }
369  }
370  alac->extra_bits = 0;
371  decorr_shift = 0;
372  decorr_left_weight = 0;
373  }
374 
375  if (channels == 2 && decorr_left_weight) {
377  decorr_shift, decorr_left_weight);
378  }
379 
380  if (alac->extra_bits) {
382  alac->extra_bits, channels, alac->nb_samples);
383  }
384 
385  switch(alac->sample_size) {
386  case 16: {
387  for (ch = 0; ch < channels; ch++) {
388  int16_t *outbuffer = (int16_t *)frame->extended_data[ch_index + ch];
389  for (i = 0; i < alac->nb_samples; i++)
390  *outbuffer++ = alac->output_samples_buffer[ch][i];
391  }}
392  break;
393  case 24: {
394  for (ch = 0; ch < channels; ch++) {
395  for (i = 0; i < alac->nb_samples; i++)
396  alac->output_samples_buffer[ch][i] <<= 8;
397  }}
398  break;
399  }
400 
401  return 0;
402 }
403 
404 static int alac_decode_frame(AVCodecContext *avctx, void *data,
405  int *got_frame_ptr, AVPacket *avpkt)
406 {
407  ALACContext *alac = avctx->priv_data;
408  AVFrame *frame = data;
409  enum AlacRawDataBlockType element;
410  int channels;
411  int ch, ret, got_end;
412 
413  init_get_bits(&alac->gb, avpkt->data, avpkt->size * 8);
414 
415  got_end = 0;
416  alac->nb_samples = 0;
417  ch = 0;
418  while (get_bits_left(&alac->gb) >= 3) {
419  element = get_bits(&alac->gb, 3);
420  if (element == TYPE_END) {
421  got_end = 1;
422  break;
423  }
424  if (element > TYPE_CPE && element != TYPE_LFE) {
425  av_log(avctx, AV_LOG_ERROR, "syntax element unsupported: %d", element);
426  return AVERROR_PATCHWELCOME;
427  }
428 
429  channels = (element == TYPE_CPE) ? 2 : 1;
430  if (ch + channels > alac->channels ||
431  ff_alac_channel_layout_offsets[alac->channels - 1][ch] + channels > alac->channels) {
432  av_log(avctx, AV_LOG_ERROR, "invalid element channel count\n");
433  return AVERROR_INVALIDDATA;
434  }
435 
436  ret = decode_element(avctx, frame,
438  channels);
439  if (ret < 0 && get_bits_left(&alac->gb))
440  return ret;
441 
442  ch += channels;
443  }
444  if (!got_end) {
445  av_log(avctx, AV_LOG_ERROR, "no end tag found. incomplete packet.\n");
446  return AVERROR_INVALIDDATA;
447  }
448 
449  if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8) {
450  av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
451  avpkt->size * 8 - get_bits_count(&alac->gb));
452  }
453 
454  *got_frame_ptr = 1;
455 
456  return avpkt->size;
457 }
458 
460 {
461  ALACContext *alac = avctx->priv_data;
462 
463  int ch;
464  for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
465  av_freep(&alac->predict_error_buffer[ch]);
466  if (alac->sample_size == 16)
467  av_freep(&alac->output_samples_buffer[ch]);
468  av_freep(&alac->extra_bits_buffer[ch]);
469  }
470 
471  return 0;
472 }
473 
474 static int allocate_buffers(ALACContext *alac)
475 {
476  int ch;
477  int buf_size = alac->max_samples_per_frame * sizeof(int32_t);
478 
479  for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
481  buf_size, buf_alloc_fail);
482 
483  if (alac->sample_size == 16) {
485  buf_size, buf_alloc_fail);
486  }
487 
488  FF_ALLOC_OR_GOTO(alac->avctx, alac->extra_bits_buffer[ch],
489  buf_size, buf_alloc_fail);
490  }
491  return 0;
492 buf_alloc_fail:
493  alac_decode_close(alac->avctx);
494  return AVERROR(ENOMEM);
495 }
496 
497 static int alac_set_info(ALACContext *alac)
498 {
499  GetByteContext gb;
500 
501  bytestream2_init(&gb, alac->avctx->extradata,
502  alac->avctx->extradata_size);
503 
504  bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4
505 
506  alac->max_samples_per_frame = bytestream2_get_be32u(&gb);
507  if (!alac->max_samples_per_frame ||
508  alac->max_samples_per_frame > INT_MAX / sizeof(int32_t)) {
509  av_log(alac->avctx, AV_LOG_ERROR, "max samples per frame invalid: %u\n",
510  alac->max_samples_per_frame);
511  return AVERROR_INVALIDDATA;
512  }
513  bytestream2_skipu(&gb, 1); // compatible version
514  alac->sample_size = bytestream2_get_byteu(&gb);
515  alac->rice_history_mult = bytestream2_get_byteu(&gb);
516  alac->rice_initial_history = bytestream2_get_byteu(&gb);
517  alac->rice_limit = bytestream2_get_byteu(&gb);
518  alac->channels = bytestream2_get_byteu(&gb);
519  bytestream2_get_be16u(&gb); // maxRun
520  bytestream2_get_be32u(&gb); // max coded frame size
521  bytestream2_get_be32u(&gb); // average bitrate
522  bytestream2_get_be32u(&gb); // samplerate
523 
524  return 0;
525 }
526 
528 {
529  int ret;
530  ALACContext *alac = avctx->priv_data;
531  alac->avctx = avctx;
532 
533  /* initialize from the extradata */
535  av_log(avctx, AV_LOG_ERROR, "alac: extradata is too small\n");
536  return AVERROR_INVALIDDATA;
537  }
538  if (alac_set_info(alac)) {
539  av_log(avctx, AV_LOG_ERROR, "alac: set_info failed\n");
540  return -1;
541  }
542 
543  switch (alac->sample_size) {
544  case 16: avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
545  break;
546  case 24:
547  case 32: avctx->sample_fmt = AV_SAMPLE_FMT_S32P;
548  break;
549  default: avpriv_request_sample(avctx, "Sample depth %d", alac->sample_size);
550  return AVERROR_PATCHWELCOME;
551  }
552  avctx->bits_per_raw_sample = alac->sample_size;
553 
554  if (alac->channels < 1) {
555  av_log(avctx, AV_LOG_WARNING, "Invalid channel count\n");
556  alac->channels = avctx->channels;
557  } else {
558  if (alac->channels > ALAC_MAX_CHANNELS)
559  alac->channels = avctx->channels;
560  else
561  avctx->channels = alac->channels;
562  }
563  if (avctx->channels > ALAC_MAX_CHANNELS) {
564  av_log(avctx, AV_LOG_ERROR, "Unsupported channel count: %d\n",
565  avctx->channels);
566  return AVERROR_PATCHWELCOME;
567  }
568  avctx->channel_layout = ff_alac_channel_layouts[alac->channels - 1];
569 
570  if ((ret = allocate_buffers(alac)) < 0) {
571  av_log(avctx, AV_LOG_ERROR, "Error allocating buffers\n");
572  return ret;
573  }
574 
575  return 0;
576 }
577 
579  .name = "alac",
580  .long_name = NULL_IF_CONFIG_SMALL("ALAC (Apple Lossless Audio Codec)"),
581  .type = AVMEDIA_TYPE_AUDIO,
582  .id = AV_CODEC_ID_ALAC,
583  .priv_data_size = sizeof(ALACContext),
587  .capabilities = CODEC_CAP_DR1,
588 };
#define extra_bits(eb)
Definition: intrax8.c:152
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:54
int nb_samples
number of samples in the current frame
Definition: alac.c:75
This structure describes decoded (raw) audio or video data.
Definition: frame.h:107
#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:240
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:129
static int decode_element(AVCodecContext *avctx, AVFrame *frame, int ch_index, int channels)
Definition: alac.c:250
Definition: aac.h:56
Definition: aac.h:50
int size
Definition: avcodec.h:974
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:2488
int32_t * extra_bits_buffer[2]
Definition: alac.c:66
AVCodec.
Definition: avcodec.h:2755
static int get_sbits(GetBitContext *s, int n)
Definition: get_bits.h:226
static int get_sbits_long(GetBitContext *s, int n)
Read 0-32 bits as a signed integer.
Definition: get_bits.h:340
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:198
int32_t * predict_error_buffer[2]
Definition: alac.c:64
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:269
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1787
uint8_t
#define av_cold
Definition: attributes.h:66
uint8_t rice_initial_history
Definition: alac.c:71
Definition: aac.h:52
static av_cold int alac_decode_close(AVCodecContext *avctx)
Definition: alac.c:459
#define b
Definition: input.c:52
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1162
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:711
const char data[16]
Definition: mxf.c:66
uint8_t * data
Definition: avcodec.h:973
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:194
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:65
static int alac_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: alac.c:404
signed 32 bits, planar
Definition: samplefmt.h:59
int extra_bits
number of extra bits beyond 16-bit
Definition: alac.c:74
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:555
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:240
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:123
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:158
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:142
static int sign_only(int v)
Definition: alac.c:153
AlacRawDataBlockType
Definition: alac_data.h:26
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:148
const char * name
Name of the codec implementation.
Definition: avcodec.h:2762
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:1840
#define ALAC_MAX_CHANNELS
Definition: alac_data.h:38
uint32_t max_samples_per_frame
Definition: alac.c:68
static void output_buffer(int16_t **samples, int nchan, int blocksize, int32_t **buffer)
Definition: shorten.c:257
static void decorrelate_stereo(int32_t *buffer[2], int nb_samples, int decorr_shift, int decorr_left_weight)
Definition: alac.c:221
audio channel layout utility functions
#define FFMIN(a, b)
Definition: common.h:57
#define FFSIGN(a)
Definition: common.h:53
GetBitContext gb
Definition: alac.c:61
int32_t
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
Definition: get_bits.h:254
static int alac_set_info(ALACContext *alac)
Definition: alac.c:497
static char buffer[20]
Definition: seek-test.c:31
uint8_t rice_history_mult
Definition: alac.c:70
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
#define AVERROR_PATCHWELCOME
Not yet implemented in Libav, patches welcome.
Definition: error.h:57
NULL
Definition: eval.c:55
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:1054
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:489
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:575
int extradata_size
Definition: avcodec.h:1163
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:271
static void skip_bits(GetBitContext *s, int n)
Definition: get_bits.h:263
static void rice_decompress(ALACContext *alac, int32_t *output_buffer, int nb_samples, int bps, int rice_history_mult)
Definition: alac.c:100
static unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
Definition: alac.c:78
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:375
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
Definition: get_bits.h:304
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:69
int channels
Definition: alac.c:62
AVCodec ff_alac_decoder
Definition: alac.c:578
common internal api header.
static av_cold int alac_decode_init(AVCodecContext *avctx)
Definition: alac.c:527
#define FF_ALLOC_OR_GOTO(ctx, p, size, label)
Definition: internal.h:109
uint8_t rice_limit
Definition: alac.c:72
unsigned bps
Definition: movenc.c:823
static av_cold int init(AVCodecParserContext *s)
Definition: h264_parser.c:498
void * priv_data
Definition: avcodec.h:1090
static int allocate_buffers(ALACContext *alac)
Definition: alac.c:474
int channels
number of audio channels
Definition: avcodec.h:1780
#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: frame.h:141
This structure stores compressed data.
Definition: avcodec.h:950
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:151
for(j=16;j >0;--j)