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, *buf3, *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  int header_emu = 0;
90 
91  header = AV_RB32(buf2);
92  ret = avpriv_mpegaudio_decode_header(&h, header);
93  if (ret != 0 || end - buf2 < h.frame_size)
94  break;
95 
96  for (buf3 = buf2 + 4; buf3 < buf2 + h.frame_size; buf3++) {
97  uint32_t next_sync = AV_RB32(buf3);
98  header_emu += (next_sync & MP3_MASK) == (header & MP3_MASK);
99  }
100  if (header_emu > 2)
101  break;
102  buf2 += h.frame_size;
103  framesizes += h.frame_size;
104  }
105  max_frames = FFMAX(max_frames, frames);
106  max_framesizes = FFMAX(max_framesizes, framesizes);
107  if (buf == buf0) {
108  first_frames= frames;
109  if (buf2 == end + sizeof(uint32_t))
110  whole_used = 1;
111  }
112  }
113  // keep this in sync with ac3 probe, both need to avoid
114  // issues with MPEG-files!
115  if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
116  else if (max_frames>200 && p->buf_size < 2*max_framesizes)return AVPROBE_SCORE_EXTENSION;
117  else if (max_frames>=4 && p->buf_size < 2*max_framesizes) return AVPROBE_SCORE_EXTENSION / 2;
118  else if (ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
120  else if (first_frames > 1 && whole_used) return 5;
121  else if (max_frames>=1 && p->buf_size < 10*max_framesizes) return 1;
122  else return 0;
123  //mpegps_mp3_unrecognized_format.mpg has max_frames=3
124 }
125 
126 static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
127 {
128  int i;
129  MP3DecContext *mp3 = s->priv_data;
130  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
131  int fill_index = (mp3->usetoc || fast_seek) && duration > 0;
132 
133  if (!filesize &&
134  !(filesize = avio_size(s->pb))) {
135  av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
136  fill_index = 0;
137  }
138 
139  for (i = 0; i < XING_TOC_COUNT; i++) {
140  uint8_t b = avio_r8(s->pb);
141  if (fill_index)
143  av_rescale(b, filesize, 256),
144  av_rescale(i, duration, XING_TOC_COUNT),
145  0, 0, AVINDEX_KEYFRAME);
146  }
147  if (fill_index)
148  mp3->xing_toc = 1;
149 }
150 
152  MPADecodeHeader *c, uint32_t spf)
153 {
154 #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
155 #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))
156 
157  uint16_t crc;
158  uint32_t v;
159 
160  char version[10];
161 
162  uint32_t peak = 0;
163  int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
164 
165  MP3DecContext *mp3 = s->priv_data;
166  static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
167  uint64_t fsize = avio_size(s->pb);
168  fsize = fsize >= avio_tell(s->pb) ? fsize - avio_tell(s->pb) : 0;
169 
170  /* Check for Xing / Info tag */
171  avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
172  v = avio_rb32(s->pb);
173  mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
174  if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
175  return;
176 
177  v = avio_rb32(s->pb);
178  if (v & XING_FLAG_FRAMES)
179  mp3->frames = avio_rb32(s->pb);
180  if (v & XING_FLAG_SIZE)
181  mp3->header_filesize = avio_rb32(s->pb);
182  if (fsize && mp3->header_filesize) {
183  uint64_t min, delta;
184  min = FFMIN(fsize, mp3->header_filesize);
185  delta = FFMAX(fsize, mp3->header_filesize) - min;
186  if (fsize > mp3->header_filesize && delta > min >> 4) {
187  mp3->frames = 0;
189  "invalid concatenated file detected - using bitrate for duration\n");
190  } else if (delta > min >> 4) {
192  "filesize and duration do not match (growing file?)\n");
193  }
194  }
195  if (v & XING_FLAG_TOC)
197  (AVRational){spf, c->sample_rate},
198  st->time_base));
199  /* VBR quality */
200  if (v & XING_FLAC_QSCALE)
201  avio_rb32(s->pb);
202 
203  /* Encoder short version string */
204  memset(version, 0, sizeof(version));
205  avio_read(s->pb, version, 9);
206 
207  /* Info Tag revision + VBR method */
208  avio_r8(s->pb);
209 
210  /* Lowpass filter value */
211  avio_r8(s->pb);
212 
213  /* ReplayGain peak */
214  v = avio_rb32(s->pb);
215  peak = av_rescale(v, 100000, 1 << 23);
216 
217  /* Radio ReplayGain */
218  v = avio_rb16(s->pb);
219 
220  if (MIDDLE_BITS(v, 13, 15) == 1) {
221  r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
222 
223  if (v & (1 << 9))
224  r_gain *= -1;
225  }
226 
227  /* Audiophile ReplayGain */
228  v = avio_rb16(s->pb);
229 
230  if (MIDDLE_BITS(v, 13, 15) == 2) {
231  a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
232 
233  if (v & (1 << 9))
234  a_gain *= -1;
235  }
236 
237  /* Encoding flags + ATH Type */
238  avio_r8(s->pb);
239 
240  /* if ABR {specified bitrate} else {minimal bitrate} */
241  avio_r8(s->pb);
242 
243  /* Encoder delays */
244  v = avio_rb24(s->pb);
245  if (AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
246  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
247  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
248  ) {
249 
250  mp3->start_pad = v>>12;
251  mp3-> end_pad = v&4095;
252  st->start_skip_samples = mp3->start_pad + 528 + 1;
253  if (mp3->frames) {
254  st->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
255  st->last_discard_sample = mp3->frames * (int64_t)spf;
256  }
257  if (!st->start_time)
259  (AVRational){1, c->sample_rate},
260  st->time_base);
261  av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
262  }
263 
264  /* Misc */
265  avio_r8(s->pb);
266 
267  /* MP3 gain */
268  avio_r8(s->pb);
269 
270  /* Preset and surround info */
271  avio_rb16(s->pb);
272 
273  /* Music length */
274  avio_rb32(s->pb);
275 
276  /* Music CRC */
277  avio_rb16(s->pb);
278 
279  /* Info Tag CRC */
280  crc = ffio_get_checksum(s->pb);
281  v = avio_rb16(s->pb);
282 
283  if (v == crc) {
284  ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
285  av_dict_set(&st->metadata, "encoder", version, 0);
286  }
287 }
288 
289 static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
290 {
291  uint32_t v;
292  MP3DecContext *mp3 = s->priv_data;
293 
294  /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
295  avio_seek(s->pb, base + 4 + 32, SEEK_SET);
296  v = avio_rb32(s->pb);
297  if (v == MKBETAG('V', 'B', 'R', 'I')) {
298  /* Check tag version */
299  if (avio_rb16(s->pb) == 1) {
300  /* skip delay and quality */
301  avio_skip(s->pb, 4);
302  mp3->header_filesize = avio_rb32(s->pb);
303  mp3->frames = avio_rb32(s->pb);
304  }
305  }
306 }
307 
308 /**
309  * Try to find Xing/Info/VBRI tags and compute duration from info therein
310  */
312 {
313  uint32_t v, spf;
315  int vbrtag_size = 0;
316  MP3DecContext *mp3 = s->priv_data;
317  int ret;
318 
320 
321  v = avio_rb32(s->pb);
322 
323  ret = avpriv_mpegaudio_decode_header(&c, v);
324  if (ret < 0)
325  return ret;
326  else if (ret == 0)
327  vbrtag_size = c.frame_size;
328  if (c.layer != 3)
329  return -1;
330 
331  spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
332 
333  mp3->frames = 0;
334  mp3->header_filesize = 0;
335 
336  mp3_parse_info_tag(s, st, &c, spf);
337  mp3_parse_vbri_tag(s, st, base);
338 
339  if (!mp3->frames && !mp3->header_filesize)
340  return -1;
341 
342  /* Skip the vbr tag frame */
343  avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
344 
345  if (mp3->frames)
346  st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
347  st->time_base);
348  if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
349  st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
350 
351  return 0;
352 }
353 
355 {
356  MP3DecContext *mp3 = s->priv_data;
357  AVStream *st;
358  int64_t off;
359  int ret;
360  int i;
361 
362  s->metadata = s->internal->id3v2_meta;
363  s->internal->id3v2_meta = NULL;
364 
365  st = avformat_new_stream(s, NULL);
366  if (!st)
367  return AVERROR(ENOMEM);
368 
372  st->start_time = 0;
373 
374  // lcm of all mp3 sample rates
375  avpriv_set_pts_info(st, 64, 1, 14112000);
376 
377  s->pb->maxsize = -1;
378  off = avio_tell(s->pb);
379 
381  ff_id3v1_read(s);
382 
383  if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
384  mp3->filesize = avio_size(s->pb);
385 
386  if (mp3_parse_vbr_tags(s, st, off) < 0)
387  avio_seek(s->pb, off, SEEK_SET);
388 
389  ret = ff_replaygain_export(st, s->metadata);
390  if (ret < 0)
391  return ret;
392 
393  off = avio_tell(s->pb);
394  for (i = 0; i < 64 * 1024; i++) {
395  uint32_t header, header2;
396  int frame_size;
397  if (!(i&1023))
398  ffio_ensure_seekback(s->pb, i + 1024 + 4);
399  frame_size = check(s->pb, off + i, &header);
400  if (frame_size > 0) {
401  ret = avio_seek(s->pb, off, SEEK_SET);
402  if (ret < 0)
403  return ret;
404  ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
405  ret = check(s->pb, off + i + frame_size, &header2);
406  if (ret >= 0 &&
407  (header & MP3_MASK) == (header2 & MP3_MASK))
408  {
409  av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
410  ret = avio_seek(s->pb, off + i, SEEK_SET);
411  if (ret < 0)
412  return ret;
413  break;
414  } else if (ret == CHECK_SEEK_FAILED) {
415  av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
416  return AVERROR(EINVAL);
417  }
418  } else if (frame_size == CHECK_SEEK_FAILED) {
419  av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
420  return AVERROR(EINVAL);
421  }
422  ret = avio_seek(s->pb, off, SEEK_SET);
423  if (ret < 0)
424  return ret;
425  }
426 
427  // the seek index is relative to the end of the xing vbr headers
428  for (i = 0; i < st->nb_index_entries; i++)
429  st->index_entries[i].pos += avio_tell(s->pb);
430 
431  /* the parameters will be extracted from the compressed bitstream */
432  return 0;
433 }
434 
435 #define MP3_PACKET_SIZE 1024
436 
438 {
439  MP3DecContext *mp3 = s->priv_data;
440  int ret, size;
441  int64_t pos;
442 
443  size = MP3_PACKET_SIZE;
444  pos = avio_tell(s->pb);
445  if (mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
446  size= FFMIN(size, mp3->filesize - pos);
447 
448  ret = av_get_packet(s->pb, pkt, size);
449  if (ret <= 0) {
450  if(ret<0)
451  return ret;
452  return AVERROR_EOF;
453  }
454 
455  pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
456  pkt->stream_index = 0;
457 
458  return ret;
459 }
460 
461 #define SEEK_WINDOW 4096
462 
463 static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
464 {
465  int64_t ret = avio_seek(pb, pos, SEEK_SET);
466  uint8_t header_buf[4];
467  unsigned header;
468  MPADecodeHeader sd;
469  if (ret < 0)
470  return CHECK_SEEK_FAILED;
471 
472  ret = avio_read(pb, &header_buf[0], 4);
473  /* We should always find four bytes for a valid mpa header. */
474  if (ret < 4)
475  return CHECK_SEEK_FAILED;
476 
477  header = AV_RB32(&header_buf[0]);
478  if (ff_mpa_check_header(header) < 0)
479  return CHECK_WRONG_HEADER;
480  if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
481  return CHECK_WRONG_HEADER;
482 
483  if (ret_header)
484  *ret_header = header;
485  return sd.frame_size;
486 }
487 
488 static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
489 {
490  int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
491  int64_t best_pos;
492  int best_score, i, j;
493  int64_t ret;
494 
495  avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
496  ret = avio_seek(s->pb, target_pos, SEEK_SET);
497  if (ret < 0)
498  return ret;
499 
500 #define MIN_VALID 3
501  best_pos = target_pos;
502  best_score = 999;
503  for (i = 0; i < SEEK_WINDOW; i++) {
504  int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
505  int64_t candidate = -1;
506  int score = 999;
507 
508  if (pos < 0)
509  continue;
510 
511  for (j = 0; j < MIN_VALID; j++) {
512  ret = check(s->pb, pos, NULL);
513  if (ret < 0) {
514  if (ret == CHECK_WRONG_HEADER) {
515  break;
516  } else if (ret == CHECK_SEEK_FAILED) {
517  av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
518  return AVERROR(EINVAL);
519  }
520  }
521  if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
522  candidate = pos;
523  score = FFABS(MIN_VALID/2-j);
524  }
525  pos += ret;
526  }
527  if (best_score > score && j == MIN_VALID) {
528  best_pos = candidate;
529  best_score = score;
530  if(score == 0)
531  break;
532  }
533  }
534 
535  return avio_seek(s->pb, best_pos, SEEK_SET);
536 }
537 
538 static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
539  int flags)
540 {
541  MP3DecContext *mp3 = s->priv_data;
542  AVIndexEntry *ie, ie1;
543  AVStream *st = s->streams[0];
544  int64_t best_pos;
545  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
546  int64_t filesize = mp3->header_filesize;
547 
548  if (filesize <= 0) {
549  int64_t size = avio_size(s->pb);
550  if (size > 0 && size > s->internal->data_offset)
551  filesize = size - s->internal->data_offset;
552  }
553 
554  if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
555  int64_t ret = av_index_search_timestamp(st, timestamp, flags);
556 
557  // NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
558  // for bigger files.
559  av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
560 
561  if (ret < 0)
562  return ret;
563 
564  ie = &st->index_entries[ret];
565  } else if (fast_seek && st->duration > 0 && filesize > 0) {
566  if (!mp3->is_cbr)
567  av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
568 
569  ie = &ie1;
570  timestamp = av_clip64(timestamp, 0, st->duration);
571  ie->timestamp = timestamp;
572  ie->pos = av_rescale(timestamp, filesize, st->duration) + s->internal->data_offset;
573  } else {
574  return -1; // generic index code
575  }
576 
577  best_pos = mp3_sync(s, ie->pos, flags);
578  if (best_pos < 0)
579  return best_pos;
580 
581  if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
582  int frame_duration = av_rescale(st->duration, 1, mp3->frames);
583  ie1.timestamp = frame_duration * av_rescale(best_pos - s->internal->data_offset, mp3->frames, mp3->header_filesize);
584  }
585 
586  ff_update_cur_dts(s, st, ie->timestamp);
587  return 0;
588 }
589 
590 static const AVOption options[] = {
591  { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
592  { NULL },
593 };
594 
595 static const AVClass demuxer_class = {
596  .class_name = "mp3",
597  .item_name = av_default_item_name,
598  .option = options,
599  .version = LIBAVUTIL_VERSION_INT,
600  .category = AV_CLASS_CATEGORY_DEMUXER,
601 };
602 
604  .name = "mp3",
605  .long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
606  .read_probe = mp3_read_probe,
607  .read_header = mp3_read_header,
608  .read_packet = mp3_read_packet,
609  .read_seek = mp3_seek,
610  .priv_data_size = sizeof(MP3DecContext),
612  .extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
613  .priv_class = &demuxer_class,
614 };
#define AVSEEK_FLAG_BACKWARD
Definition: avformat.h:2517
#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:2051
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:1157
#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:4931
int64_t pos
Definition: avformat.h:809
#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:1165
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3987
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:279
#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:1109
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1810
static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
Definition: mp3dec.c:126
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:1357
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:1965
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:437
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:538
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:1098
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4504
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:1425
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:1488
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:308
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:803
#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:4016
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:816
#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:1597
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2166
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:810
#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:354
#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:569
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3983
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:1500
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:461
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:435
#define FFMIN(a, b)
Definition: common.h:96
static int check(AVIOContext *pb, int64_t pos, uint32_t *header)
Definition: mp3dec.c:463
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:151
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:488
#define s(width, name)
Definition: cbs_vp9.c:257
int xing_toc
Definition: mp3dec.c:49
AVDictionary * metadata
Definition: avformat.h:944
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:289
#define MIN_VALID
Stream structure.
Definition: avformat.h:880
#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:2140
Libavcodec external API header.
AVIOContext * pb
I/O context.
Definition: avformat.h:1399
#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:1111
Describe the class of an AVClass context structure.
Definition: log.h:67
static const AVOption options[]
Definition: mp3dec.c:590
#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:564
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:929
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:595
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:919
AVInputFormat ff_mp3_demuxer
Definition: mp3dec.c:603
#define AV_PKT_FLAG_CORRUPT
The packet content is corrupted.
Definition: avcodec.h:1527
#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:1514
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:1385
#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:311
#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:1027
static int64_t fsize(FILE *f)
Definition: audiomatch.c:28
int stream_index
Definition: avcodec.h:1496
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:909
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:1471
int64_t last_discard_sample
The sample after last sample that is intended to be discarded after first_discard_sample.
Definition: avformat.h:1172