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  int available;
91 
92  header = AV_RB32(buf2);
93  ret = avpriv_mpegaudio_decode_header(&h, header);
94  if (ret != 0)
95  break;
96 
97  available = FFMIN(h.frame_size, end - buf2);
98  for (buf3 = buf2 + 4; buf3 < buf2 + available; buf3++) {
99  uint32_t next_sync = AV_RB32(buf3);
100  header_emu += (next_sync & MP3_MASK) == (header & MP3_MASK);
101  }
102  if (header_emu > 2)
103  break;
104  framesizes += h.frame_size;
105  if (available < h.frame_size) {
106  frames++;
107  break;
108  }
109  buf2 += h.frame_size;
110  }
111  max_frames = FFMAX(max_frames, frames);
112  max_framesizes = FFMAX(max_framesizes, framesizes);
113  if (buf == buf0) {
114  first_frames= frames;
115  if (buf2 == end + sizeof(uint32_t))
116  whole_used = 1;
117  }
118  }
119  // keep this in sync with ac3 probe, both need to avoid
120  // issues with MPEG-files!
121  if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
122  else if (max_frames>200 && p->buf_size < 2*max_framesizes)return AVPROBE_SCORE_EXTENSION;
123  else if (max_frames>=4 && p->buf_size < 2*max_framesizes) return AVPROBE_SCORE_EXTENSION / 2;
124  else if (ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
126  else if (first_frames > 1 && whole_used) return 5;
127  else if (max_frames>=1 && p->buf_size < 10*max_framesizes) return 1;
128  else return 0;
129  //mpegps_mp3_unrecognized_format.mpg has max_frames=3
130 }
131 
132 static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
133 {
134  int i;
135  MP3DecContext *mp3 = s->priv_data;
136  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
137  int fill_index = (mp3->usetoc || fast_seek) && duration > 0;
138 
139  if (!filesize &&
140  !(filesize = avio_size(s->pb))) {
141  av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
142  fill_index = 0;
143  }
144 
145  for (i = 0; i < XING_TOC_COUNT; i++) {
146  uint8_t b = avio_r8(s->pb);
147  if (fill_index)
149  av_rescale(b, filesize, 256),
150  av_rescale(i, duration, XING_TOC_COUNT),
151  0, 0, AVINDEX_KEYFRAME);
152  }
153  if (fill_index)
154  mp3->xing_toc = 1;
155 }
156 
158  MPADecodeHeader *c, uint32_t spf)
159 {
160 #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
161 #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))
162 
163  uint16_t crc;
164  uint32_t v;
165 
166  char version[10];
167 
168  uint32_t peak = 0;
169  int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
170 
171  MP3DecContext *mp3 = s->priv_data;
172  static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
173  uint64_t fsize = avio_size(s->pb);
174  fsize = fsize >= avio_tell(s->pb) ? fsize - avio_tell(s->pb) : 0;
175 
176  /* Check for Xing / Info tag */
177  avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
178  v = avio_rb32(s->pb);
179  mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
180  if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
181  return;
182 
183  v = avio_rb32(s->pb);
184  if (v & XING_FLAG_FRAMES)
185  mp3->frames = avio_rb32(s->pb);
186  if (v & XING_FLAG_SIZE)
187  mp3->header_filesize = avio_rb32(s->pb);
188  if (fsize && mp3->header_filesize) {
189  uint64_t min, delta;
190  min = FFMIN(fsize, mp3->header_filesize);
191  delta = FFMAX(fsize, mp3->header_filesize) - min;
192  if (fsize > mp3->header_filesize && delta > min >> 4) {
193  mp3->frames = 0;
195  "invalid concatenated file detected - using bitrate for duration\n");
196  } else if (delta > min >> 4) {
198  "filesize and duration do not match (growing file?)\n");
199  }
200  }
201  if (v & XING_FLAG_TOC)
203  (AVRational){spf, c->sample_rate},
204  st->time_base));
205  /* VBR quality */
206  if (v & XING_FLAC_QSCALE)
207  avio_rb32(s->pb);
208 
209  /* Encoder short version string */
210  memset(version, 0, sizeof(version));
211  avio_read(s->pb, version, 9);
212 
213  /* Info Tag revision + VBR method */
214  avio_r8(s->pb);
215 
216  /* Lowpass filter value */
217  avio_r8(s->pb);
218 
219  /* ReplayGain peak */
220  v = avio_rb32(s->pb);
221  peak = av_rescale(v, 100000, 1 << 23);
222 
223  /* Radio ReplayGain */
224  v = avio_rb16(s->pb);
225 
226  if (MIDDLE_BITS(v, 13, 15) == 1) {
227  r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
228 
229  if (v & (1 << 9))
230  r_gain *= -1;
231  }
232 
233  /* Audiophile ReplayGain */
234  v = avio_rb16(s->pb);
235 
236  if (MIDDLE_BITS(v, 13, 15) == 2) {
237  a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
238 
239  if (v & (1 << 9))
240  a_gain *= -1;
241  }
242 
243  /* Encoding flags + ATH Type */
244  avio_r8(s->pb);
245 
246  /* if ABR {specified bitrate} else {minimal bitrate} */
247  avio_r8(s->pb);
248 
249  /* Encoder delays */
250  v = avio_rb24(s->pb);
251  if (AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
252  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
253  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
254  ) {
255 
256  mp3->start_pad = v>>12;
257  mp3-> end_pad = v&4095;
258  st->start_skip_samples = mp3->start_pad + 528 + 1;
259  if (mp3->frames) {
260  st->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
261  st->last_discard_sample = mp3->frames * (int64_t)spf;
262  }
263  if (!st->start_time)
265  (AVRational){1, c->sample_rate},
266  st->time_base);
267  av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
268  }
269 
270  /* Misc */
271  avio_r8(s->pb);
272 
273  /* MP3 gain */
274  avio_r8(s->pb);
275 
276  /* Preset and surround info */
277  avio_rb16(s->pb);
278 
279  /* Music length */
280  avio_rb32(s->pb);
281 
282  /* Music CRC */
283  avio_rb16(s->pb);
284 
285  /* Info Tag CRC */
286  crc = ffio_get_checksum(s->pb);
287  v = avio_rb16(s->pb);
288 
289  if (v == crc) {
290  ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
291  av_dict_set(&st->metadata, "encoder", version, 0);
292  }
293 }
294 
295 static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
296 {
297  uint32_t v;
298  MP3DecContext *mp3 = s->priv_data;
299 
300  /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
301  avio_seek(s->pb, base + 4 + 32, SEEK_SET);
302  v = avio_rb32(s->pb);
303  if (v == MKBETAG('V', 'B', 'R', 'I')) {
304  /* Check tag version */
305  if (avio_rb16(s->pb) == 1) {
306  /* skip delay and quality */
307  avio_skip(s->pb, 4);
308  mp3->header_filesize = avio_rb32(s->pb);
309  mp3->frames = avio_rb32(s->pb);
310  }
311  }
312 }
313 
314 /**
315  * Try to find Xing/Info/VBRI tags and compute duration from info therein
316  */
318 {
319  uint32_t v, spf;
321  int vbrtag_size = 0;
322  MP3DecContext *mp3 = s->priv_data;
323  int ret;
324 
326 
327  v = avio_rb32(s->pb);
328 
329  ret = avpriv_mpegaudio_decode_header(&c, v);
330  if (ret < 0)
331  return ret;
332  else if (ret == 0)
333  vbrtag_size = c.frame_size;
334  if (c.layer != 3)
335  return -1;
336 
337  spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
338 
339  mp3->frames = 0;
340  mp3->header_filesize = 0;
341 
342  mp3_parse_info_tag(s, st, &c, spf);
343  mp3_parse_vbri_tag(s, st, base);
344 
345  if (!mp3->frames && !mp3->header_filesize)
346  return -1;
347 
348  /* Skip the vbr tag frame */
349  avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
350 
351  if (mp3->frames)
352  st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
353  st->time_base);
354  if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
355  st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
356 
357  return 0;
358 }
359 
361 {
362  MP3DecContext *mp3 = s->priv_data;
363  AVStream *st;
364  int64_t off;
365  int ret;
366  int i;
367 
368  s->metadata = s->internal->id3v2_meta;
369  s->internal->id3v2_meta = NULL;
370 
371  st = avformat_new_stream(s, NULL);
372  if (!st)
373  return AVERROR(ENOMEM);
374 
378  st->start_time = 0;
379 
380  // lcm of all mp3 sample rates
381  avpriv_set_pts_info(st, 64, 1, 14112000);
382 
383  s->pb->maxsize = -1;
384  off = avio_tell(s->pb);
385 
387  ff_id3v1_read(s);
388 
389  if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
390  mp3->filesize = avio_size(s->pb);
391 
392  if (mp3_parse_vbr_tags(s, st, off) < 0)
393  avio_seek(s->pb, off, SEEK_SET);
394 
395  ret = ff_replaygain_export(st, s->metadata);
396  if (ret < 0)
397  return ret;
398 
399  off = avio_tell(s->pb);
400  for (i = 0; i < 64 * 1024; i++) {
401  uint32_t header, header2;
402  int frame_size;
403  if (!(i&1023))
404  ffio_ensure_seekback(s->pb, i + 1024 + 4);
405  frame_size = check(s->pb, off + i, &header);
406  if (frame_size > 0) {
407  ret = avio_seek(s->pb, off, SEEK_SET);
408  if (ret < 0)
409  return ret;
410  ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
411  ret = check(s->pb, off + i + frame_size, &header2);
412  if (ret >= 0 &&
413  (header & MP3_MASK) == (header2 & MP3_MASK))
414  {
415  av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
416  ret = avio_seek(s->pb, off + i, SEEK_SET);
417  if (ret < 0)
418  return ret;
419  break;
420  } else if (ret == CHECK_SEEK_FAILED) {
421  av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
422  return AVERROR(EINVAL);
423  }
424  } else if (frame_size == CHECK_SEEK_FAILED) {
425  av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
426  return AVERROR(EINVAL);
427  }
428  ret = avio_seek(s->pb, off, SEEK_SET);
429  if (ret < 0)
430  return ret;
431  }
432 
433  // the seek index is relative to the end of the xing vbr headers
434  for (i = 0; i < st->nb_index_entries; i++)
435  st->index_entries[i].pos += avio_tell(s->pb);
436 
437  /* the parameters will be extracted from the compressed bitstream */
438  return 0;
439 }
440 
441 #define MP3_PACKET_SIZE 1024
442 
444 {
445  MP3DecContext *mp3 = s->priv_data;
446  int ret, size;
447  int64_t pos;
448 
449  size = MP3_PACKET_SIZE;
450  pos = avio_tell(s->pb);
451  if (mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
452  size= FFMIN(size, mp3->filesize - pos);
453 
454  ret = av_get_packet(s->pb, pkt, size);
455  if (ret <= 0) {
456  if(ret<0)
457  return ret;
458  return AVERROR_EOF;
459  }
460 
461  pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
462  pkt->stream_index = 0;
463 
464  return ret;
465 }
466 
467 #define SEEK_WINDOW 4096
468 
469 static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
470 {
471  int64_t ret = avio_seek(pb, pos, SEEK_SET);
472  uint8_t header_buf[4];
473  unsigned header;
474  MPADecodeHeader sd;
475  if (ret < 0)
476  return CHECK_SEEK_FAILED;
477 
478  ret = avio_read(pb, &header_buf[0], 4);
479  /* We should always find four bytes for a valid mpa header. */
480  if (ret < 4)
481  return CHECK_SEEK_FAILED;
482 
483  header = AV_RB32(&header_buf[0]);
484  if (ff_mpa_check_header(header) < 0)
485  return CHECK_WRONG_HEADER;
486  if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
487  return CHECK_WRONG_HEADER;
488 
489  if (ret_header)
490  *ret_header = header;
491  return sd.frame_size;
492 }
493 
494 static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
495 {
496  int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
497  int64_t best_pos;
498  int best_score, i, j;
499  int64_t ret;
500 
501  avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
502  ret = avio_seek(s->pb, target_pos, SEEK_SET);
503  if (ret < 0)
504  return ret;
505 
506 #define MIN_VALID 3
507  best_pos = target_pos;
508  best_score = 999;
509  for (i = 0; i < SEEK_WINDOW; i++) {
510  int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
511  int64_t candidate = -1;
512  int score = 999;
513 
514  if (pos < 0)
515  continue;
516 
517  for (j = 0; j < MIN_VALID; j++) {
518  ret = check(s->pb, pos, NULL);
519  if (ret < 0) {
520  if (ret == CHECK_WRONG_HEADER) {
521  break;
522  } else if (ret == CHECK_SEEK_FAILED) {
523  av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
524  return AVERROR(EINVAL);
525  }
526  }
527  if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
528  candidate = pos;
529  score = FFABS(MIN_VALID/2-j);
530  }
531  pos += ret;
532  }
533  if (best_score > score && j == MIN_VALID) {
534  best_pos = candidate;
535  best_score = score;
536  if(score == 0)
537  break;
538  }
539  }
540 
541  return avio_seek(s->pb, best_pos, SEEK_SET);
542 }
543 
544 static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
545  int flags)
546 {
547  MP3DecContext *mp3 = s->priv_data;
548  AVIndexEntry *ie, ie1;
549  AVStream *st = s->streams[0];
550  int64_t best_pos;
551  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
552  int64_t filesize = mp3->header_filesize;
553 
554  if (filesize <= 0) {
555  int64_t size = avio_size(s->pb);
556  if (size > 0 && size > s->internal->data_offset)
557  filesize = size - s->internal->data_offset;
558  }
559 
560  if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
561  int64_t ret = av_index_search_timestamp(st, timestamp, flags);
562 
563  // NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
564  // for bigger files.
565  av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
566 
567  if (ret < 0)
568  return ret;
569 
570  ie = &st->index_entries[ret];
571  } else if (fast_seek && st->duration > 0 && filesize > 0) {
572  if (!mp3->is_cbr)
573  av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
574 
575  ie = &ie1;
576  timestamp = av_clip64(timestamp, 0, st->duration);
577  ie->timestamp = timestamp;
578  ie->pos = av_rescale(timestamp, filesize, st->duration) + s->internal->data_offset;
579  } else {
580  return -1; // generic index code
581  }
582 
583  best_pos = mp3_sync(s, ie->pos, flags);
584  if (best_pos < 0)
585  return best_pos;
586 
587  if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
588  int frame_duration = av_rescale(st->duration, 1, mp3->frames);
589  ie1.timestamp = frame_duration * av_rescale(best_pos - s->internal->data_offset, mp3->frames, mp3->header_filesize);
590  }
591 
592  ff_update_cur_dts(s, st, ie->timestamp);
593  return 0;
594 }
595 
596 static const AVOption options[] = {
597  { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
598  { NULL },
599 };
600 
601 static const AVClass demuxer_class = {
602  .class_name = "mp3",
603  .item_name = av_default_item_name,
604  .option = options,
605  .version = LIBAVUTIL_VERSION_INT,
606  .category = AV_CLASS_CATEGORY_DEMUXER,
607 };
608 
610  .name = "mp3",
611  .long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
612  .read_probe = mp3_read_probe,
613  .read_header = mp3_read_header,
614  .read_packet = mp3_read_packet,
615  .read_seek = mp3_seek,
616  .priv_data_size = sizeof(MP3DecContext),
618  .extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
619  .priv_class = &demuxer_class,
620 };
#define AVSEEK_FLAG_BACKWARD
Definition: avformat.h:2507
#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:346
version
Definition: libkvazaar.c:317
AVOption.
Definition: opt.h:248
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:1983
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:1152
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
#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:4869
int64_t pos
Definition: avformat.h:805
#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:1160
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
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:253
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: avformat.h:1105
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1804
static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
Definition: mp3dec.c:132
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:341
static AVPacket pkt
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:775
#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:1351
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:1897
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:443
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:790
static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: mp3dec.c:544
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:92
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:1094
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4450
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:1419
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:1482
int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header)
static const uint8_t xing_offtbl[2][2]
Definition: mp3enc.c:138
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:210
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:305
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:799
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:637
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:89
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:812
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1591
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2100
if no frame is available
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:806
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
static int mp3_read_header(AVFormatContext *s)
Definition: mp3dec.c:360
unsigned int pos
Definition: spdifenc.c:410
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:215
preferred ID for decoding MPEG audio layer 1, 2 or 3
Definition: codec_id.h:415
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
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: packet.h:369
static int mp3_read_probe(const AVProbeData *p)
Definition: mp3dec.c:67
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:628
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
#define SEEK_WINDOW
Definition: mp3dec.c:467
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:616
#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:783
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:441
#define FFMIN(a, b)
Definition: common.h:96
static int check(AVIOContext *pb, int64_t pos, uint32_t *header)
Definition: mp3dec.c:469
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:157
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:494
#define s(width, name)
Definition: cbs_vp9.c:257
int xing_toc
Definition: mp3dec.c:49
AVDictionary * metadata
Definition: avformat.h:940
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:602
static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
Definition: mp3dec.c:295
#define MIN_VALID
Stream structure.
Definition: avformat.h:876
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
#define AV_LOG_INFO
Standard information.
Definition: log.h:205
int frame_size
Definition: mxfenc.c:2166
Libavcodec external API header.
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
#define XING_FLAG_FRAMES
Definition: mp3dec.c:38
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:1107
Describe the class of an AVClass context structure.
Definition: log.h:67
static const AVOption options[]
Definition: mp3dec.c:596
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:463
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:279
#define XING_FLAC_QSCALE
Definition: mp3dec.c:41
unsigned long ffio_get_checksum(AVIOContext *s)
Definition: aviobuf.c:608
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:451
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
#define flags(name, subs,...)
Definition: cbs_av1.c:560
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:994
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:925
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:601
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:915
AVInputFormat ff_mp3_demuxer
Definition: mp3dec.c:609
#define AV_PKT_FLAG_CORRUPT
The packet content is corrupted.
Definition: packet.h:402
#define MKBETAG(a, b, c, d)
Definition: common.h:407
#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:1508
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:1379
#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:317
#define ID3v1_TAG_SIZE
Definition: id3v1.h:27
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:650
#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:1023
static int64_t fsize(FILE *f)
Definition: audiomatch.c:28
int stream_index
Definition: packet.h:365
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:905
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: packet.h:340
int i
Definition: input.c:407
int64_t last_discard_sample
The sample after last sample that is intended to be discarded after first_discard_sample.
Definition: avformat.h:1167