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/codec_id.h"
36 #include "libavcodec/mpegaudiodecheader.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;
56 } MP3DecContext;
57 
58 enum CheckRet {
59  CHECK_WRONG_HEADER = -1,
60  CHECK_SEEK_FAILED = -2,
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++) {
88  MPADecodeHeader h;
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)
125  return p->buf_size < PROBE_BUF_MAX ? AVPROBE_SCORE_EXTENSION / 4 : AVPROBE_SCORE_EXTENSION - 2;
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)
148  av_add_index_entry(s->streams[0],
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 
157 static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
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  FFStream *const sti = ffstream(st);
164  uint16_t crc;
165  uint32_t v;
166 
167  char version[10];
168 
169  uint32_t peak = 0;
170  int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
171 
172  MP3DecContext *mp3 = s->priv_data;
173  static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
174  uint64_t fsize = avio_size(s->pb);
175  int64_t pos = avio_tell(s->pb);
176  fsize = fsize >= pos ? fsize - pos : 0;
177 
178  /* Check for Xing / Info tag */
179  avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
180  v = avio_rb32(s->pb);
181  mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
182  if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
183  return;
184 
185  v = avio_rb32(s->pb);
186  if (v & XING_FLAG_FRAMES)
187  mp3->frames = avio_rb32(s->pb);
188  if (v & XING_FLAG_SIZE)
189  mp3->header_filesize = avio_rb32(s->pb);
190  if (fsize && mp3->header_filesize) {
191  uint64_t min, delta;
192  min = FFMIN(fsize, mp3->header_filesize);
193  delta = FFMAX(fsize, mp3->header_filesize) - min;
194  if (fsize > mp3->header_filesize && delta > min >> 4) {
195  mp3->frames = 0;
196  av_log(s, AV_LOG_WARNING,
197  "invalid concatenated file detected - using bitrate for duration\n");
198  } else if (delta > min >> 4) {
199  av_log(s, AV_LOG_WARNING,
200  "filesize and duration do not match (growing file?)\n");
201  }
202  }
203  if (v & XING_FLAG_TOC)
204  read_xing_toc(s, mp3->header_filesize, av_rescale_q(mp3->frames,
205  (AVRational){spf, c->sample_rate},
206  st->time_base));
207  /* VBR quality */
208  if (v & XING_FLAC_QSCALE)
209  avio_rb32(s->pb);
210 
211  /* Encoder short version string */
212  memset(version, 0, sizeof(version));
213  avio_read(s->pb, version, 9);
214 
215  /* Info Tag revision + VBR method */
216  avio_r8(s->pb);
217 
218  /* Lowpass filter value */
219  avio_r8(s->pb);
220 
221  /* ReplayGain peak */
222  v = avio_rb32(s->pb);
223  peak = av_rescale(v, 100000, 1 << 23);
224 
225  /* Radio ReplayGain */
226  v = avio_rb16(s->pb);
227 
228  if (MIDDLE_BITS(v, 13, 15) == 1) {
229  r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
230 
231  if (v & (1 << 9))
232  r_gain *= -1;
233  }
234 
235  /* Audiophile ReplayGain */
236  v = avio_rb16(s->pb);
237 
238  if (MIDDLE_BITS(v, 13, 15) == 2) {
239  a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
240 
241  if (v & (1 << 9))
242  a_gain *= -1;
243  }
244 
245  /* Encoding flags + ATH Type */
246  avio_r8(s->pb);
247 
248  /* if ABR {specified bitrate} else {minimal bitrate} */
249  avio_r8(s->pb);
250 
251  /* Encoder delays */
252  v = avio_rb24(s->pb);
253  if (AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
254  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
255  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
256  ) {
257 
258  mp3->start_pad = v>>12;
259  mp3-> end_pad = v&4095;
260  sti->start_skip_samples = mp3->start_pad + 528 + 1;
261  if (mp3->frames) {
262  sti->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
263  sti->last_discard_sample = mp3->frames * (int64_t)spf;
264  }
265  if (!st->start_time)
266  st->start_time = av_rescale_q(sti->start_skip_samples,
267  (AVRational){1, c->sample_rate},
268  st->time_base);
269  av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
270  }
271 
272  /* Misc */
273  avio_r8(s->pb);
274 
275  /* MP3 gain */
276  avio_r8(s->pb);
277 
278  /* Preset and surround info */
279  avio_rb16(s->pb);
280 
281  /* Music length */
282  avio_rb32(s->pb);
283 
284  /* Music CRC */
285  avio_rb16(s->pb);
286 
287  /* Info Tag CRC */
288  crc = ffio_get_checksum(s->pb);
289  v = avio_rb16(s->pb);
290 
291  if (v == crc) {
292  ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
293  av_dict_set(&st->metadata, "encoder", version, 0);
294  }
295 }
296 
297 static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
298 {
299  uint32_t v;
300  MP3DecContext *mp3 = s->priv_data;
301 
302  /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
303  avio_seek(s->pb, base + 4 + 32, SEEK_SET);
304  v = avio_rb32(s->pb);
305  if (v == MKBETAG('V', 'B', 'R', 'I')) {
306  /* Check tag version */
307  if (avio_rb16(s->pb) == 1) {
308  /* skip delay and quality */
309  avio_skip(s->pb, 4);
310  mp3->header_filesize = avio_rb32(s->pb);
311  mp3->frames = avio_rb32(s->pb);
312  }
313  }
314 }
315 
316 /**
317  * Try to find Xing/Info/VBRI tags and compute duration from info therein
318  */
319 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
320 {
321  uint32_t v, spf;
322  MPADecodeHeader c;
323  int vbrtag_size = 0;
324  MP3DecContext *mp3 = s->priv_data;
325  int ret;
326 
327  ffio_init_checksum(s->pb, ff_crcA001_update, 0);
328 
329  v = avio_rb32(s->pb);
330 
331  ret = avpriv_mpegaudio_decode_header(&c, v);
332  if (ret < 0)
333  return ret;
334  else if (ret == 0)
335  vbrtag_size = c.frame_size;
336  if (c.layer != 3)
337  return -1;
338 
339  spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
340 
341  mp3->frames = 0;
342  mp3->header_filesize = 0;
343 
344  mp3_parse_info_tag(s, st, &c, spf);
345  mp3_parse_vbri_tag(s, st, base);
346 
347  if (!mp3->frames && !mp3->header_filesize)
348  return -1;
349 
350  /* Skip the vbr tag frame */
351  avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
352 
353  if (mp3->frames)
354  st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
355  st->time_base);
356  if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
357  st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
358 
359  return 0;
360 }
361 
362 static int mp3_read_header(AVFormatContext *s)
363 {
364  FFFormatContext *const si = ffformatcontext(s);
365  MP3DecContext *mp3 = s->priv_data;
366  AVStream *st;
367  FFStream *sti;
368  int64_t off;
369  int ret;
370  int i;
371 
372  s->metadata = si->id3v2_meta;
373  si->id3v2_meta = NULL;
374 
375  st = avformat_new_stream(s, NULL);
376  if (!st)
377  return AVERROR(ENOMEM);
378  sti = ffstream(st);
379 
380  st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
381  st->codecpar->codec_id = AV_CODEC_ID_MP3;
382  sti->need_parsing = AVSTREAM_PARSE_FULL_RAW;
383  st->start_time = 0;
384 
385  // lcm of all mp3 sample rates
386  avpriv_set_pts_info(st, 64, 1, 14112000);
387 
388  ffiocontext(s->pb)->maxsize = -1;
389  off = avio_tell(s->pb);
390 
391  if (!av_dict_count(s->metadata))
392  ff_id3v1_read(s);
393 
394  if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
395  mp3->filesize = avio_size(s->pb);
396 
397  if (mp3_parse_vbr_tags(s, st, off) < 0)
398  avio_seek(s->pb, off, SEEK_SET);
399 
400  ret = ff_replaygain_export(st, s->metadata);
401  if (ret < 0)
402  return ret;
403 
404  off = avio_tell(s->pb);
405  for (i = 0; i < 64 * 1024; i++) {
406  uint32_t header, header2;
407  int frame_size;
408  if (!(i&1023))
409  ffio_ensure_seekback(s->pb, i + 1024 + 4);
410  frame_size = check(s->pb, off + i, &header);
411  if (frame_size > 0) {
412  ret = avio_seek(s->pb, off, SEEK_SET);
413  if (ret < 0)
414  return ret;
415  ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
416  ret = check(s->pb, off + i + frame_size, &header2);
417  if (ret >= 0 &&
418  (header & MP3_MASK) == (header2 & MP3_MASK))
419  {
420  av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
421  ret = avio_seek(s->pb, off + i, SEEK_SET);
422  if (ret < 0)
423  return ret;
424  break;
425  } else if (ret == CHECK_SEEK_FAILED) {
426  av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
427  return AVERROR(EINVAL);
428  }
429  } else if (frame_size == CHECK_SEEK_FAILED) {
430  av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
431  return AVERROR(EINVAL);
432  }
433  ret = avio_seek(s->pb, off, SEEK_SET);
434  if (ret < 0)
435  return ret;
436  }
437 
438  off = avio_tell(s->pb);
439  // the seek index is relative to the end of the xing vbr headers
440  for (int i = 0; i < sti->nb_index_entries; i++)
441  sti->index_entries[i].pos += off;
442 
443  /* the parameters will be extracted from the compressed bitstream */
444  return 0;
445 }
446 
447 #define MP3_PACKET_SIZE 1024
448 
449 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
450 {
451  MP3DecContext *mp3 = s->priv_data;
452  int ret, size;
453  int64_t pos;
454 
455  size = MP3_PACKET_SIZE;
456  pos = avio_tell(s->pb);
457  if (mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
458  size= FFMIN(size, mp3->filesize - pos);
459 
460  ret = av_get_packet(s->pb, pkt, size);
461  if (ret <= 0) {
462  if(ret<0)
463  return ret;
464  return AVERROR_EOF;
465  }
466 
467  pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
468  pkt->stream_index = 0;
469 
470  return ret;
471 }
472 
473 #define SEEK_WINDOW 4096
474 
475 static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
476 {
477  int64_t ret = avio_seek(pb, pos, SEEK_SET);
478  uint8_t header_buf[4];
479  unsigned header;
480  MPADecodeHeader sd;
481  if (ret < 0)
482  return CHECK_SEEK_FAILED;
483 
484  ret = avio_read(pb, &header_buf[0], 4);
485  /* We should always find four bytes for a valid mpa header. */
486  if (ret < 4)
487  return CHECK_SEEK_FAILED;
488 
489  header = AV_RB32(&header_buf[0]);
490  if (ff_mpa_check_header(header) < 0)
491  return CHECK_WRONG_HEADER;
492  if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
493  return CHECK_WRONG_HEADER;
494 
495  if (ret_header)
496  *ret_header = header;
497  return sd.frame_size;
498 }
499 
500 static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
501 {
502  int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
503  int64_t best_pos;
504  int best_score, i, j;
505  int64_t ret;
506 
507  avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
508  ret = avio_seek(s->pb, target_pos, SEEK_SET);
509  if (ret < 0)
510  return ret;
511 
512 #define MIN_VALID 3
513  best_pos = target_pos;
514  best_score = 999;
515  for (i = 0; i < SEEK_WINDOW; i++) {
516  int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
517  int64_t candidate = -1;
518  int score = 999;
519 
520  if (pos < 0)
521  continue;
522 
523  for (j = 0; j < MIN_VALID; j++) {
524  ret = check(s->pb, pos, NULL);
525  if (ret < 0) {
526  if (ret == CHECK_WRONG_HEADER) {
527  break;
528  } else if (ret == CHECK_SEEK_FAILED) {
529  av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
530  return AVERROR(EINVAL);
531  }
532  }
533  if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
534  candidate = pos;
535  score = FFABS(MIN_VALID/2-j);
536  }
537  pos += ret;
538  }
539  if (best_score > score && j == MIN_VALID) {
540  best_pos = candidate;
541  best_score = score;
542  if(score == 0)
543  break;
544  }
545  }
546 
547  return avio_seek(s->pb, best_pos, SEEK_SET);
548 }
549 
550 static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
551  int flags)
552 {
553  FFFormatContext *const si = ffformatcontext(s);
554  MP3DecContext *mp3 = s->priv_data;
555  AVIndexEntry *ie, ie1;
556  AVStream *st = s->streams[0];
557  FFStream *const sti = ffstream(st);
558  int64_t best_pos;
559  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
560  int64_t filesize = mp3->header_filesize;
561 
562  if (filesize <= 0) {
563  int64_t size = avio_size(s->pb);
564  if (size > 0 && size > si->data_offset)
565  filesize = size - si->data_offset;
566  }
567 
568  if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
569  int64_t ret = av_index_search_timestamp(st, timestamp, flags);
570 
571  // NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
572  // for bigger files.
573  av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
574 
575  if (ret < 0)
576  return ret;
577 
578  ie = &sti->index_entries[ret];
579  } else if (fast_seek && st->duration > 0 && filesize > 0) {
580  if (!mp3->is_cbr)
581  av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
582 
583  ie = &ie1;
584  timestamp = av_clip64(timestamp, 0, st->duration);
585  ie->timestamp = timestamp;
586  ie->pos = av_rescale(timestamp, filesize, st->duration) + si->data_offset;
587  } else {
588  return -1; // generic index code
589  }
590 
591  best_pos = mp3_sync(s, ie->pos, flags);
592  if (best_pos < 0)
593  return best_pos;
594 
595  if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
596  int frame_duration = av_rescale(st->duration, 1, mp3->frames);
597  ie1.timestamp = frame_duration * av_rescale(best_pos - si->data_offset, mp3->frames, mp3->header_filesize);
598  }
599 
600  avpriv_update_cur_dts(s, st, ie->timestamp);
601  return 0;
602 }
603 
604 static const AVOption options[] = {
605  { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
606  { NULL },
607 };
608 
609 static const AVClass demuxer_class = {
610  .class_name = "mp3",
611  .item_name = av_default_item_name,
612  .option = options,
613  .version = LIBAVUTIL_VERSION_INT,
614  .category = AV_CLASS_CATEGORY_DEMUXER,
615 };
616 
617 const AVInputFormat ff_mp3_demuxer = {
618  .name = "mp3",
619  .long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
620  .read_probe = mp3_read_probe,
621  .read_header = mp3_read_header,
622  .read_packet = mp3_read_packet,
623  .read_seek = mp3_seek,
624  .priv_data_size = sizeof(MP3DecContext),
625  .flags = AVFMT_GENERIC_INDEX,
626  .extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
627  .priv_class = &demuxer_class,
628 };
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
ID3v1_TAG_SIZE
#define ID3v1_TAG_SIZE
Definition: id3v1.h:27
AVERROR
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
opt.h
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:768
xing_offtbl
static const uint8_t xing_offtbl[2][2]
Definition: mp3enc.c:138
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
XING_FLAC_QSCALE
#define XING_FLAC_QSCALE
Definition: mp3dec.c:41
ffiocontext
static av_always_inline FFIOContext * ffiocontext(AVIOContext *ctx)
Definition: avio_internal.h:82
demuxer_class
static const AVClass demuxer_class
Definition: mp3dec.c:609
mp3_read_packet
static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mp3dec.c:449
ffformatcontext
static av_always_inline FFFormatContext * ffformatcontext(AVFormatContext *s)
Definition: internal.h:189
ff_replaygain_export
int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
Parse replaygain tags and export them as per-stream side data.
Definition: replaygain.c:90
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
av_dict_count
int av_dict_count(const AVDictionary *m)
Get number of entries in dictionary.
Definition: dict.c:35
MP3DecContext
Definition: mp3dec.c:46
id3v2.h
FFStream::first_discard_sample
int64_t first_discard_sample
If not 0, the first audio sample that should be discarded from the stream.
Definition: internal.h:318
ff_replaygain_export_raw
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:69
mpegaudiodecheader.h
ff_id3v1_read
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:278
AVOption
AVOption.
Definition: opt.h:247
b
#define b
Definition: input.c:40
MPADecodeHeader
Definition: mpegaudiodecheader.h:47
AV_LOG_VERBOSE
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:196
base
uint8_t base
Definition: vp3data.h:141
mathematics.h
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:450
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
MP3_MASK
#define MP3_MASK
Definition: mpegaudiodecheader.h:33
id3v1.h
avio_size
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:352
ffio_get_checksum
unsigned long ffio_get_checksum(AVIOContext *s)
Definition: aviobuf.c:612
AVIndexEntry
Definition: avformat.h:801
AVINDEX_KEYFRAME
#define AVINDEX_KEYFRAME
Definition: avformat.h:809
crc.h
MIDDLE_BITS
#define MIDDLE_BITS(k, m, n)
XING_FLAG_FRAMES
#define XING_FLAG_FRAMES
Definition: mp3dec.c:38
ffstream
static av_always_inline FFStream * ffstream(AVStream *st)
Definition: internal.h:432
av_add_index_entry
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: seek.c:117
frames
if it could not because there are no more frames
Definition: filter_design.txt:266
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:504
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:476
AV_CODEC_ID_MP3
@ AV_CODEC_ID_MP3
preferred ID for decoding MPEG audio layer 1, 2 or 3
Definition: codec_id.h:424
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:985
read_xing_toc
static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
Definition: mp3dec.c:132
av_clip64
#define av_clip64
Definition: common.h:99
MP3DecContext::filesize
int64_t filesize
Definition: mp3dec.c:48
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:790
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
avpriv_mpegaudio_decode_header
int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header)
Definition: mpegaudiodecheader.c:34
AVInputFormat
Definition: avformat.h:650
AV_PKT_FLAG_CORRUPT
#define AV_PKT_FLAG_CORRUPT
The packet content is corrupted.
Definition: packet.h:429
SEEK_WINDOW
#define SEEK_WINDOW
Definition: mp3dec.c:473
codec_id.h
duration
int64_t duration
Definition: movenc.c:64
MP3_PACKET_SIZE
#define MP3_PACKET_SIZE
Definition: mp3dec.c:447
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:655
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:449
frame_size
int frame_size
Definition: mxfenc.c:2199
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVIndexEntry::timestamp
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:803
MP3DecContext::end_pad
int end_pad
Definition: mp3dec.c:51
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
FFFormatContext::data_offset
int64_t data_offset
offset of the first packet
Definition: internal.h:99
av_rescale_q
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:141
MP3DecContext::xing_toc
int xing_toc
Definition: mp3dec.c:49
XING_FLAG_TOC
#define XING_FLAG_TOC
Definition: mp3dec.c:40
fsize
static int64_t fsize(FILE *f)
Definition: audiomatch.c:29
AV_CLASS_CATEGORY_DEMUXER
@ AV_CLASS_CATEGORY_DEMUXER
Definition: log.h:33
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:65
FFFormatContext
Definition: internal.h:73
FFStream::need_parsing
enum AVStreamParseType need_parsing
Definition: internal.h:405
AVFormatContext
Format I/O context.
Definition: avformat.h:1200
avpriv_update_cur_dts
void avpriv_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: seek.c:32
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1095
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AVSEEK_FLAG_BACKWARD
#define AVSEEK_FLAG_BACKWARD
Definition: avformat.h:2275
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
AVStream::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avformat.h:965
NULL
#define NULL
Definition: coverity.c:32
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
FFStream::nb_index_entries
int nb_index_entries
Definition: internal.h:279
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:447
AVStream::metadata
AVDictionary * metadata
Definition: avformat.h:1006
c
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
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:457
FFIOContext::maxsize
int64_t maxsize
max filesize, used to limit allocations
Definition: avio_internal.h:47
FFFormatContext::id3v2_meta
AVDictionary * id3v2_meta
ID3v2 tag useful for MP3 demuxing.
Definition: internal.h:176
MP3DecContext::start_pad
int start_pad
Definition: mp3dec.c:50
mp3_parse_vbr_tags
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:319
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
avio_rb24
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:783
ff_mpa_check_header
static int ff_mpa_check_header(uint32_t header)
Definition: mpegaudiodecheader.h:62
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
ff_mp3_demuxer
const AVInputFormat ff_mp3_demuxer
Definition: mp3dec.c:617
FFStream
Definition: internal.h:194
FFStream::last_discard_sample
int64_t last_discard_sample
The sample after last sample that is intended to be discarded after first_discard_sample.
Definition: internal.h:325
mp3_read_header
static int mp3_read_header(AVFormatContext *s)
Definition: mp3dec.c:362
MP3DecContext::frames
unsigned frames
Definition: mp3dec.c:53
size
int size
Definition: twinvq_data.h:10344
CHECK_SEEK_FAILED
@ CHECK_SEEK_FAILED
Definition: mp3dec.c:60
ID3v2_DEFAULT_MAGIC
#define ID3v2_DEFAULT_MAGIC
Default magic bytes for ID3v2 header: "ID3".
Definition: id3v2.h:35
MKBETAG
#define MKBETAG(a, b, c, d)
Definition: macros.h:56
AV_RB32
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:96
XING_FLAG_SIZE
#define XING_FLAG_SIZE
Definition: mp3dec.c:39
ffio_init_checksum
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:620
header
static const uint8_t header[24]
Definition: sdr2.c:67
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:632
ffio_ensure_seekback
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:1055
XING_TOC_COUNT
#define XING_TOC_COUNT
Definition: mp3dec.c:43
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:379
FFStream::start_skip_samples
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: internal.h:310
version
version
Definition: libkvazaar.c:313
AV_LOG_INFO
#define AV_LOG_INFO
Standard information.
Definition: log.h:191
MP3DecContext::is_cbr
int is_cbr
Definition: mp3dec.c:55
PROBE_BUF_MAX
#define PROBE_BUF_MAX
Definition: internal.h:37
AVFMT_FLAG_FAST_SEEK
#define AVFMT_FLAG_FAST_SEEK
Enable fast, but inaccurate seeks for some formats.
Definition: avformat.h:1340
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
avio_internal.h
available
if no frame is available
Definition: filter_design.txt:166
mp3_parse_info_tag
static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st, MPADecodeHeader *c, uint32_t spf)
Definition: mp3dec.c:157
mp3_seek
static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: mp3dec.c:550
delta
float delta
Definition: vorbis_enc_data.h:430
AV_OPT_FLAG_DECODING_PARAM
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:278
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
mp3_sync
static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
Definition: mp3dec.c:500
mp3_read_probe
static int mp3_read_probe(const AVProbeData *p)
Definition: mp3dec.c:67
ff_crcA001_update
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:606
av_rescale
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:128
av_get_packet
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:197
ff_id3v2_tag_len
int ff_id3v2_tag_len(const uint8_t *buf)
Get the length of an ID3v2 tag.
Definition: id3v2.c:156
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:935
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:260
AVClass::class_name
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:71
avio_rb16
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:775
CheckRet
CheckRet
Definition: mp3dec.c:58
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
dict.h
AVIO_SEEKABLE_NORMAL
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:641
mp3_parse_vbri_tag
static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
Definition: mp3dec.c:297
MP3DecContext::header_filesize
unsigned header_filesize
Definition: mp3dec.c:54
AVIndexEntry::pos
int64_t pos
Definition: avformat.h:802
AVSTREAM_PARSE_FULL_RAW
@ AVSTREAM_PARSE_FULL_RAW
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:796
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, 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:1196
AVPacket::stream_index
int stream_index
Definition: packet.h:375
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
MP3DecContext::usetoc
int usetoc
Definition: mp3dec.c:52
options
static const AVOption options[]
Definition: mp3dec.c:604
FFStream::index_entries
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: internal.h:277
check
static int check(AVIOContext *pb, int64_t pos, uint32_t *header)
Definition: mp3dec.c:475
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AV_OPT_TYPE_BOOL
@ AV_OPT_TYPE_BOOL
Definition: opt.h:241
av_dict_set
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
int32_t
int32_t
Definition: audioconvert.c:56
replaygain.h
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:89
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
h
h
Definition: vp9dsp_template.c:2038
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base.
Definition: avformat.h:975
avstring.h
MIN_VALID
#define MIN_VALID
ff_id3v2_match
int ff_id3v2_match(const uint8_t *buf, const char *magic)
Detect ID3v2 Header.
Definition: id3v2.c:143
av_index_search_timestamp
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: seek.c:237
CHECK_WRONG_HEADER
@ CHECK_WRONG_HEADER
Definition: mp3dec.c:59
min
float min
Definition: vorbis_enc_data.h:429
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