FFmpeg
mp3dec.c
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1 /*
2  * MP3 demuxer
3  * Copyright (c) 2003 Fabrice Bellard
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 #include "libavutil/opt.h"
23 #include "libavutil/avstring.h"
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/crc.h"
26 #include "libavutil/dict.h"
27 #include "libavutil/mathematics.h"
28 #include "avformat.h"
29 #include "internal.h"
30 #include "avio_internal.h"
31 #include "id3v2.h"
32 #include "id3v1.h"
33 #include "replaygain.h"
34 
35 #include "libavcodec/avcodec.h"
37 
38 #define XING_FLAG_FRAMES 0x01
39 #define XING_FLAG_SIZE 0x02
40 #define XING_FLAG_TOC 0x04
41 #define XING_FLAC_QSCALE 0x08
42 
43 #define XING_TOC_COUNT 100
44 
45 
46 typedef struct {
47  AVClass *class;
48  int64_t filesize;
49  int xing_toc;
50  int start_pad;
51  int end_pad;
52  int usetoc;
53  unsigned frames; /* Total number of frames in file */
54  unsigned header_filesize; /* Total number of bytes in the stream */
55  int is_cbr;
57 
58 enum CheckRet {
61 };
62 
63 static int check(AVIOContext *pb, int64_t pos, uint32_t *header);
64 
65 /* mp3 read */
66 
67 static int mp3_read_probe(const AVProbeData *p)
68 {
69  int max_frames, first_frames = 0;
70  int whole_used = 0;
71  int frames, ret;
72  int framesizes, max_framesizes;
73  uint32_t header;
74  const uint8_t *buf, *buf0, *buf2, *end;
75 
76  buf0 = p->buf;
77  end = p->buf + p->buf_size - sizeof(uint32_t);
78  while (buf0 < end && !*buf0)
79  buf0++;
80 
81  max_frames = 0;
82  max_framesizes = 0;
83  buf = buf0;
84 
85  for (; buf < end; buf = buf2+1) {
86  buf2 = buf;
87  for (framesizes = frames = 0; buf2 < end; frames++) {
89 
90  header = AV_RB32(buf2);
91  ret = avpriv_mpegaudio_decode_header(&h, header);
92  if (ret != 0)
93  break;
94  buf2 += h.frame_size;
95  framesizes += h.frame_size;
96  }
97  max_frames = FFMAX(max_frames, frames);
98  max_framesizes = FFMAX(max_framesizes, framesizes);
99  if (buf == buf0) {
100  first_frames= frames;
101  if (buf2 == end + sizeof(uint32_t))
102  whole_used = 1;
103  }
104  }
105  // keep this in sync with ac3 probe, both need to avoid
106  // issues with MPEG-files!
107  if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
108  else if (max_frames>200 && p->buf_size < 2*max_framesizes)return AVPROBE_SCORE_EXTENSION;
109  else if (max_frames>=4 && p->buf_size < 2*max_framesizes) return AVPROBE_SCORE_EXTENSION / 2;
110  else if (ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
112  else if (first_frames > 1 && whole_used) return 5;
113  else if (max_frames>=1 && p->buf_size < 10*max_framesizes) return 1;
114  else return 0;
115  //mpegps_mp3_unrecognized_format.mpg has max_frames=3
116 }
117 
118 static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
119 {
120  int i;
121  MP3DecContext *mp3 = s->priv_data;
122  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
123  int fill_index = (mp3->usetoc || fast_seek) && duration > 0;
124 
125  if (!filesize &&
126  !(filesize = avio_size(s->pb))) {
127  av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
128  fill_index = 0;
129  }
130 
131  for (i = 0; i < XING_TOC_COUNT; i++) {
132  uint8_t b = avio_r8(s->pb);
133  if (fill_index)
135  av_rescale(b, filesize, 256),
136  av_rescale(i, duration, XING_TOC_COUNT),
137  0, 0, AVINDEX_KEYFRAME);
138  }
139  if (fill_index)
140  mp3->xing_toc = 1;
141 }
142 
144  MPADecodeHeader *c, uint32_t spf)
145 {
146 #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
147 #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))
148 
149  uint16_t crc;
150  uint32_t v;
151 
152  char version[10];
153 
154  uint32_t peak = 0;
155  int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
156 
157  MP3DecContext *mp3 = s->priv_data;
158  static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
159  uint64_t fsize = avio_size(s->pb);
160  fsize = fsize >= avio_tell(s->pb) ? fsize - avio_tell(s->pb) : 0;
161 
162  /* Check for Xing / Info tag */
163  avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
164  v = avio_rb32(s->pb);
165  mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
166  if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
167  return;
168 
169  v = avio_rb32(s->pb);
170  if (v & XING_FLAG_FRAMES)
171  mp3->frames = avio_rb32(s->pb);
172  if (v & XING_FLAG_SIZE)
173  mp3->header_filesize = avio_rb32(s->pb);
174  if (fsize && mp3->header_filesize) {
175  uint64_t min, delta;
176  min = FFMIN(fsize, mp3->header_filesize);
177  delta = FFMAX(fsize, mp3->header_filesize) - min;
178  if (fsize > mp3->header_filesize && delta > min >> 4) {
179  mp3->frames = 0;
181  "invalid concatenated file detected - using bitrate for duration\n");
182  } else if (delta > min >> 4) {
184  "filesize and duration do not match (growing file?)\n");
185  }
186  }
187  if (v & XING_FLAG_TOC)
189  (AVRational){spf, c->sample_rate},
190  st->time_base));
191  /* VBR quality */
192  if (v & XING_FLAC_QSCALE)
193  avio_rb32(s->pb);
194 
195  /* Encoder short version string */
196  memset(version, 0, sizeof(version));
197  avio_read(s->pb, version, 9);
198 
199  /* Info Tag revision + VBR method */
200  avio_r8(s->pb);
201 
202  /* Lowpass filter value */
203  avio_r8(s->pb);
204 
205  /* ReplayGain peak */
206  v = avio_rb32(s->pb);
207  peak = av_rescale(v, 100000, 1 << 23);
208 
209  /* Radio ReplayGain */
210  v = avio_rb16(s->pb);
211 
212  if (MIDDLE_BITS(v, 13, 15) == 1) {
213  r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
214 
215  if (v & (1 << 9))
216  r_gain *= -1;
217  }
218 
219  /* Audiophile ReplayGain */
220  v = avio_rb16(s->pb);
221 
222  if (MIDDLE_BITS(v, 13, 15) == 2) {
223  a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
224 
225  if (v & (1 << 9))
226  a_gain *= -1;
227  }
228 
229  /* Encoding flags + ATH Type */
230  avio_r8(s->pb);
231 
232  /* if ABR {specified bitrate} else {minimal bitrate} */
233  avio_r8(s->pb);
234 
235  /* Encoder delays */
236  v = avio_rb24(s->pb);
237  if (AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
238  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
239  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
240  ) {
241 
242  mp3->start_pad = v>>12;
243  mp3-> end_pad = v&4095;
244  st->start_skip_samples = mp3->start_pad + 528 + 1;
245  if (mp3->frames) {
246  st->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
247  st->last_discard_sample = mp3->frames * (int64_t)spf;
248  }
249  if (!st->start_time)
251  (AVRational){1, c->sample_rate},
252  st->time_base);
253  av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
254  }
255 
256  /* Misc */
257  avio_r8(s->pb);
258 
259  /* MP3 gain */
260  avio_r8(s->pb);
261 
262  /* Preset and surround info */
263  avio_rb16(s->pb);
264 
265  /* Music length */
266  avio_rb32(s->pb);
267 
268  /* Music CRC */
269  avio_rb16(s->pb);
270 
271  /* Info Tag CRC */
272  crc = ffio_get_checksum(s->pb);
273  v = avio_rb16(s->pb);
274 
275  if (v == crc) {
276  ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
277  av_dict_set(&st->metadata, "encoder", version, 0);
278  }
279 }
280 
281 static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
282 {
283  uint32_t v;
284  MP3DecContext *mp3 = s->priv_data;
285 
286  /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
287  avio_seek(s->pb, base + 4 + 32, SEEK_SET);
288  v = avio_rb32(s->pb);
289  if (v == MKBETAG('V', 'B', 'R', 'I')) {
290  /* Check tag version */
291  if (avio_rb16(s->pb) == 1) {
292  /* skip delay and quality */
293  avio_skip(s->pb, 4);
294  mp3->header_filesize = avio_rb32(s->pb);
295  mp3->frames = avio_rb32(s->pb);
296  }
297  }
298 }
299 
300 /**
301  * Try to find Xing/Info/VBRI tags and compute duration from info therein
302  */
304 {
305  uint32_t v, spf;
307  int vbrtag_size = 0;
308  MP3DecContext *mp3 = s->priv_data;
309  int ret;
310 
312 
313  v = avio_rb32(s->pb);
314 
315  ret = avpriv_mpegaudio_decode_header(&c, v);
316  if (ret < 0)
317  return ret;
318  else if (ret == 0)
319  vbrtag_size = c.frame_size;
320  if (c.layer != 3)
321  return -1;
322 
323  spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
324 
325  mp3->frames = 0;
326  mp3->header_filesize = 0;
327 
328  mp3_parse_info_tag(s, st, &c, spf);
329  mp3_parse_vbri_tag(s, st, base);
330 
331  if (!mp3->frames && !mp3->header_filesize)
332  return -1;
333 
334  /* Skip the vbr tag frame */
335  avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
336 
337  if (mp3->frames)
338  st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
339  st->time_base);
340  if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
341  st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
342 
343  return 0;
344 }
345 
347 {
348  MP3DecContext *mp3 = s->priv_data;
349  AVStream *st;
350  int64_t off;
351  int ret;
352  int i;
353 
354  s->metadata = s->internal->id3v2_meta;
355  s->internal->id3v2_meta = NULL;
356 
357  st = avformat_new_stream(s, NULL);
358  if (!st)
359  return AVERROR(ENOMEM);
360 
364  st->start_time = 0;
365 
366  // lcm of all mp3 sample rates
367  avpriv_set_pts_info(st, 64, 1, 14112000);
368 
369  s->pb->maxsize = -1;
370  off = avio_tell(s->pb);
371 
373  ff_id3v1_read(s);
374 
375  if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
376  mp3->filesize = avio_size(s->pb);
377 
378  if (mp3_parse_vbr_tags(s, st, off) < 0)
379  avio_seek(s->pb, off, SEEK_SET);
380 
381  ret = ff_replaygain_export(st, s->metadata);
382  if (ret < 0)
383  return ret;
384 
385  off = avio_tell(s->pb);
386  for (i = 0; i < 64 * 1024; i++) {
387  uint32_t header, header2;
388  int frame_size;
389  if (!(i&1023))
390  ffio_ensure_seekback(s->pb, i + 1024 + 4);
391  frame_size = check(s->pb, off + i, &header);
392  if (frame_size > 0) {
393  ret = avio_seek(s->pb, off, SEEK_SET);
394  if (ret < 0)
395  return ret;
396  ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
397  ret = check(s->pb, off + i + frame_size, &header2);
398  if (ret >= 0 &&
399  (header & MP3_MASK) == (header2 & MP3_MASK))
400  {
401  av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
402  ret = avio_seek(s->pb, off + i, SEEK_SET);
403  if (ret < 0)
404  return ret;
405  break;
406  } else if (ret == CHECK_SEEK_FAILED) {
407  av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
408  return AVERROR(EINVAL);
409  }
410  } else if (frame_size == CHECK_SEEK_FAILED) {
411  av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
412  return AVERROR(EINVAL);
413  }
414  ret = avio_seek(s->pb, off, SEEK_SET);
415  if (ret < 0)
416  return ret;
417  }
418 
419  // the seek index is relative to the end of the xing vbr headers
420  for (i = 0; i < st->nb_index_entries; i++)
421  st->index_entries[i].pos += avio_tell(s->pb);
422 
423  /* the parameters will be extracted from the compressed bitstream */
424  return 0;
425 }
426 
427 #define MP3_PACKET_SIZE 1024
428 
430 {
431  MP3DecContext *mp3 = s->priv_data;
432  int ret, size;
433  int64_t pos;
434 
435  size = MP3_PACKET_SIZE;
436  pos = avio_tell(s->pb);
437  if (mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
438  size= FFMIN(size, mp3->filesize - pos);
439 
440  ret = av_get_packet(s->pb, pkt, size);
441  if (ret <= 0) {
442  if(ret<0)
443  return ret;
444  return AVERROR_EOF;
445  }
446 
447  pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
448  pkt->stream_index = 0;
449 
450  return ret;
451 }
452 
453 #define SEEK_WINDOW 4096
454 
455 static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
456 {
457  int64_t ret = avio_seek(pb, pos, SEEK_SET);
458  uint8_t header_buf[4];
459  unsigned header;
460  MPADecodeHeader sd;
461  if (ret < 0)
462  return CHECK_SEEK_FAILED;
463 
464  ret = avio_read(pb, &header_buf[0], 4);
465  /* We should always find four bytes for a valid mpa header. */
466  if (ret < 4)
467  return CHECK_SEEK_FAILED;
468 
469  header = AV_RB32(&header_buf[0]);
470  if (ff_mpa_check_header(header) < 0)
471  return CHECK_WRONG_HEADER;
472  if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
473  return CHECK_WRONG_HEADER;
474 
475  if (ret_header)
476  *ret_header = header;
477  return sd.frame_size;
478 }
479 
480 static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
481 {
482  int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
483  int64_t best_pos;
484  int best_score, i, j;
485  int64_t ret;
486 
487  avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
488  ret = avio_seek(s->pb, target_pos, SEEK_SET);
489  if (ret < 0)
490  return ret;
491 
492 #define MIN_VALID 3
493  best_pos = target_pos;
494  best_score = 999;
495  for (i = 0; i < SEEK_WINDOW; i++) {
496  int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
497  int64_t candidate = -1;
498  int score = 999;
499 
500  if (pos < 0)
501  continue;
502 
503  for (j = 0; j < MIN_VALID; j++) {
504  ret = check(s->pb, pos, NULL);
505  if (ret < 0) {
506  if (ret == CHECK_WRONG_HEADER) {
507  break;
508  } else if (ret == CHECK_SEEK_FAILED) {
509  av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
510  return AVERROR(EINVAL);
511  }
512  }
513  if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
514  candidate = pos;
515  score = FFABS(MIN_VALID/2-j);
516  }
517  pos += ret;
518  }
519  if (best_score > score && j == MIN_VALID) {
520  best_pos = candidate;
521  best_score = score;
522  if(score == 0)
523  break;
524  }
525  }
526 
527  return avio_seek(s->pb, best_pos, SEEK_SET);
528 }
529 
530 static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
531  int flags)
532 {
533  MP3DecContext *mp3 = s->priv_data;
534  AVIndexEntry *ie, ie1;
535  AVStream *st = s->streams[0];
536  int64_t best_pos;
537  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
538  int64_t filesize = mp3->header_filesize;
539 
540  if (filesize <= 0) {
541  int64_t size = avio_size(s->pb);
542  if (size > 0 && size > s->internal->data_offset)
543  filesize = size - s->internal->data_offset;
544  }
545 
546  if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
547  int64_t ret = av_index_search_timestamp(st, timestamp, flags);
548 
549  // NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
550  // for bigger files.
551  av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
552 
553  if (ret < 0)
554  return ret;
555 
556  ie = &st->index_entries[ret];
557  } else if (fast_seek && st->duration > 0 && filesize > 0) {
558  if (!mp3->is_cbr)
559  av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
560 
561  ie = &ie1;
562  timestamp = av_clip64(timestamp, 0, st->duration);
563  ie->timestamp = timestamp;
564  ie->pos = av_rescale(timestamp, filesize, st->duration) + s->internal->data_offset;
565  } else {
566  return -1; // generic index code
567  }
568 
569  best_pos = mp3_sync(s, ie->pos, flags);
570  if (best_pos < 0)
571  return best_pos;
572 
573  if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
574  int frame_duration = av_rescale(st->duration, 1, mp3->frames);
575  ie1.timestamp = frame_duration * av_rescale(best_pos - s->internal->data_offset, mp3->frames, mp3->header_filesize);
576  }
577 
578  ff_update_cur_dts(s, st, ie->timestamp);
579  return 0;
580 }
581 
582 static const AVOption options[] = {
583  { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
584  { NULL },
585 };
586 
587 static const AVClass demuxer_class = {
588  .class_name = "mp3",
589  .item_name = av_default_item_name,
590  .option = options,
591  .version = LIBAVUTIL_VERSION_INT,
592  .category = AV_CLASS_CATEGORY_DEMUXER,
593 };
594 
596  .name = "mp3",
597  .long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
598  .read_probe = mp3_read_probe,
599  .read_header = mp3_read_header,
600  .read_packet = mp3_read_packet,
601  .read_seek = mp3_seek,
602  .priv_data_size = sizeof(MP3DecContext),
604  .extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
605  .priv_class = &demuxer_class,
606 };
#define AVSEEK_FLAG_BACKWARD
Definition: avformat.h:2518
#define NULL
Definition: coverity.c:32
AVDictionary * id3v2_meta
ID3v2 tag useful for MP3 demuxing.
Definition: internal.h:139
Bytestream IO Context.
Definition: avio.h:161
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:339
AVOption.
Definition: opt.h:246
int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags)
Add an index entry into a sorted list.
Definition: utils.c:2049
int64_t start_skip_samples
If not 0, the number of samples that should be skipped from the start of the stream (the samples are ...
Definition: avformat.h:1158
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4929
int64_t pos
Definition: avformat.h:810
#define MP3_MASK
int64_t data_offset
offset of the first packet
Definition: internal.h:80
int64_t first_discard_sample
If not 0, the first audio sample that should be discarded from the stream.
Definition: avformat.h:1166
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3968
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:235
#define ID3v2_DEFAULT_MAGIC
Default magic bytes for ID3v2 header: "ID3".
Definition: id3v2.h:35
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: avformat.h:1110
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1811
static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
Definition: mp3dec.c:118
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:334
int version
Definition: avisynth_c.h:858
static AVPacket pkt
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:788
#define PROBE_BUF_MAX
Definition: internal.h:34
int64_t maxsize
max filesize, used to limit allocations This field is internal to libavformat and access from outside...
Definition: avio.h:266
unsigned frames
Definition: mp3dec.c:53
if it could not because there are no more frames
uint8_t base
Definition: vp3data.h:202
Format I/O context.
Definition: avformat.h:1358
void ff_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp)
Update cur_dts of all streams based on the given timestamp and AVStream.
Definition: utils.c:1963
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
CheckRet
Definition: mp3dec.c:58
Public dictionary API.
static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mp3dec.c:429
uint8_t
int usetoc
Definition: mp3dec.c:52
#define XING_FLAG_SIZE
Definition: mp3dec.c:39
float delta
AVOptions.
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:803
static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: mp3dec.c:530
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
enum AVStreamParseType need_parsing
Definition: avformat.h:1099
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4502
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:87
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
int64_t duration
Definition: movenc.c:63
Public header for CRC hash function implementation.
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1489
int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header)
static const uint8_t xing_offtbl[2][2]
Definition: mp3enc.c:126
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:192
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:310
ptrdiff_t size
Definition: opengl_enc.c:100
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static const uint8_t header[24]
Definition: sdr2.c:67
int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
Parse replaygain tags and export them as per-stream side data.
Definition: replaygain.c:91
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:804
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:650
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3997
int64_t filesize
Definition: mp3dec.c:48
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:142
#define AVINDEX_KEYFRAME
Definition: avformat.h:817
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1598
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2164
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:811
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
static int mp3_read_header(AVFormatContext *s)
Definition: mp3dec.c:346
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
preferred ID for decoding MPEG audio layer 1, 2 or 3
Definition: avcodec.h:566
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3964
static int ff_mpa_check_header(uint32_t header)
#define FFMAX(a, b)
Definition: common.h:94
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1486
static int mp3_read_probe(const AVProbeData *p)
Definition: mp3dec.c:67
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:641
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
#define SEEK_WINDOW
Definition: mp3dec.c:453
void ffio_init_checksum(AVIOContext *s, unsigned long(*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len), unsigned long checksum)
Definition: aviobuf.c:629
#define b
Definition: input.c:41
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:796
int64_t av_rescale(int64_t a, int64_t b, int64_t c)
Rescale a 64-bit integer with rounding to nearest.
Definition: mathematics.c:129
#define MP3_PACKET_SIZE
Definition: mp3dec.c:427
#define FFMIN(a, b)
Definition: common.h:96
static int check(AVIOContext *pb, int64_t pos, uint32_t *header)
Definition: mp3dec.c:455
int end_pad
Definition: mp3dec.c:51
static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st, MPADecodeHeader *c, uint32_t spf)
Definition: mp3dec.c:143
int32_t
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:72
static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
Definition: mp3dec.c:480
#define s(width, name)
Definition: cbs_vp9.c:257
int xing_toc
Definition: mp3dec.c:49
AVDictionary * metadata
Definition: avformat.h:945
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:615
static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
Definition: mp3dec.c:281
#define MIN_VALID
Stream structure.
Definition: avformat.h:881
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
int frame_size
Definition: mxfenc.c:2223
Libavcodec external API header.
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
#define XING_FLAG_FRAMES
Definition: mp3dec.c:38
void * buf
Definition: avisynth_c.h:766
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:70
int nb_index_entries
Definition: avformat.h:1112
Describe the class of an AVClass context structure.
Definition: log.h:67
static const AVOption options[]
Definition: mp3dec.c:582
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
Rational number (pair of numerator and denominator).
Definition: rational.h:58
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:277
#define XING_FLAC_QSCALE
Definition: mp3dec.c:41
unsigned long ffio_get_checksum(AVIOContext *s)
Definition: aviobuf.c:621
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define flags(name, subs,...)
Definition: cbs_av1.c:561
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:1054
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:930
MPEG Audio header decoder.
int is_cbr
Definition: mp3dec.c:55
Main libavformat public API header.
unsigned header_filesize
Definition: mp3dec.c:54
static const AVClass demuxer_class
Definition: mp3dec.c:587
int ff_id3v2_match(const uint8_t *buf, const char *magic)
Detect ID3v2 Header.
Definition: id3v2.c:143
int ff_replaygain_export_raw(AVStream *st, int32_t tg, uint32_t tp, int32_t ag, uint32_t ap)
Export already decoded replaygain values as per-stream side data.
Definition: replaygain.c:70
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:920
AVInputFormat ff_mp3_demuxer
Definition: mp3dec.c:595
#define AV_PKT_FLAG_CORRUPT
The packet content is corrupted.
Definition: avcodec.h:1513
#define MKBETAG(a, b, c, d)
Definition: common.h:367
#define XING_FLAG_TOC
Definition: mp3dec.c:40
#define MIDDLE_BITS(k, m, n)
#define AVFMT_FLAG_FAST_SEEK
Enable fast, but inaccurate seeks for some formats.
Definition: avformat.h:1515
int ff_id3v2_tag_len(const uint8_t *buf)
Get the length of an ID3v2 tag.
Definition: id3v2.c:156
void * priv_data
Format private data.
Definition: avformat.h:1386
#define XING_TOC_COUNT
Definition: mp3dec.c:43
static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
Try to find Xing/Info/VBRI tags and compute duration from info therein.
Definition: mp3dec.c:303
#define ID3v1_TAG_SIZE
Definition: id3v1.h:27
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
#define AV_DICT_IGNORE_SUFFIX
Return first entry in a dictionary whose first part corresponds to the search key, ignoring the suffix of the found key string.
Definition: dict.h:70
int start_pad
Definition: mp3dec.c:50
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
static int64_t fsize(FILE *f)
Definition: audiomatch.c:28
int stream_index
Definition: avcodec.h:1482
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:910
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
float min
This structure stores compressed data.
Definition: avcodec.h:1457
int64_t last_discard_sample
The sample after last sample that is intended to be discarded after first_discard_sample.
Definition: avformat.h:1173