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 #define SAME_HEADER_MASK \
46  (0xffe00000 | (3 << 17) | (3 << 10) | (3 << 19))
47 
48 typedef struct {
49  AVClass *class;
50  int64_t filesize;
51  int xing_toc;
52  int start_pad;
53  int end_pad;
54  int usetoc;
55  unsigned frames; /* Total number of frames in file */
56  unsigned header_filesize; /* Total number of bytes in the stream */
57  int is_cbr;
59 
60 enum CheckRet {
63 };
64 
65 static int check(AVIOContext *pb, int64_t pos, uint32_t *header);
66 
67 /* mp3 read */
68 
69 static int mp3_read_probe(const AVProbeData *p)
70 {
71  int max_frames, first_frames = 0;
72  int whole_used = 0;
73  int frames, ret;
74  int framesizes, max_framesizes;
75  uint32_t header;
76  const uint8_t *buf, *buf0, *buf2, *end;
77 
78  buf0 = p->buf;
79  end = p->buf + p->buf_size - sizeof(uint32_t);
80  while(buf0 < end && !*buf0)
81  buf0++;
82 
83  max_frames = 0;
84  max_framesizes = 0;
85  buf = buf0;
86 
87  for(; buf < end; buf= buf2+1) {
88  buf2 = buf;
89  for(framesizes = frames = 0; buf2 < end; frames++) {
91 
92  header = AV_RB32(buf2);
93  ret = avpriv_mpegaudio_decode_header(&h, header);
94  if (ret != 0)
95  break;
96  buf2 += h.frame_size;
97  framesizes += h.frame_size;
98  }
99  max_frames = FFMAX(max_frames, frames);
100  max_framesizes = FFMAX(max_framesizes, framesizes);
101  if(buf == buf0) {
102  first_frames= frames;
103  if (buf2 == end + sizeof(uint32_t))
104  whole_used = 1;
105  }
106  }
107  // keep this in sync with ac3 probe, both need to avoid
108  // issues with MPEG-files!
109  if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
110  else if(max_frames>200 && p->buf_size < 2*max_framesizes)return AVPROBE_SCORE_EXTENSION;
111  else if(max_frames>=4 && p->buf_size < 2*max_framesizes) return AVPROBE_SCORE_EXTENSION / 2;
112  else if(ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
114  else if(first_frames > 1 && whole_used) return 5;
115  else if(max_frames>=1 && p->buf_size < 10*max_framesizes) return 1;
116  else return 0;
117 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
118 }
119 
120 static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
121 {
122  int i;
123  MP3DecContext *mp3 = s->priv_data;
124  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
125  int fill_index = (mp3->usetoc || fast_seek) && duration > 0;
126 
127  if (!filesize &&
128  !(filesize = avio_size(s->pb))) {
129  av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
130  fill_index = 0;
131  }
132 
133  for (i = 0; i < XING_TOC_COUNT; i++) {
134  uint8_t b = avio_r8(s->pb);
135  if (fill_index)
137  av_rescale(b, filesize, 256),
138  av_rescale(i, duration, XING_TOC_COUNT),
139  0, 0, AVINDEX_KEYFRAME);
140  }
141  if (fill_index)
142  mp3->xing_toc = 1;
143 }
144 
146  MPADecodeHeader *c, uint32_t spf)
147 {
148 #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
149 #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))
150 
151  uint16_t crc;
152  uint32_t v;
153 
154  char version[10];
155 
156  uint32_t peak = 0;
157  int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
158 
159  MP3DecContext *mp3 = s->priv_data;
160  static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
161  uint64_t fsize = avio_size(s->pb);
162  fsize = fsize >= avio_tell(s->pb) ? fsize - avio_tell(s->pb) : 0;
163 
164  /* Check for Xing / Info tag */
165  avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
166  v = avio_rb32(s->pb);
167  mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
168  if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
169  return;
170 
171  v = avio_rb32(s->pb);
172  if (v & XING_FLAG_FRAMES)
173  mp3->frames = avio_rb32(s->pb);
174  if (v & XING_FLAG_SIZE)
175  mp3->header_filesize = avio_rb32(s->pb);
176  if (fsize && mp3->header_filesize) {
177  uint64_t min, delta;
178  min = FFMIN(fsize, mp3->header_filesize);
179  delta = FFMAX(fsize, mp3->header_filesize) - min;
180  if (fsize > mp3->header_filesize && delta > min >> 4) {
181  mp3->frames = 0;
183  "invalid concatenated file detected - using bitrate for duration\n");
184  } else if (delta > min >> 4) {
186  "filesize and duration do not match (growing file?)\n");
187  }
188  }
189  if (v & XING_FLAG_TOC)
191  (AVRational){spf, c->sample_rate},
192  st->time_base));
193  /* VBR quality */
194  if (v & XING_FLAC_QSCALE)
195  avio_rb32(s->pb);
196 
197  /* Encoder short version string */
198  memset(version, 0, sizeof(version));
199  avio_read(s->pb, version, 9);
200 
201  /* Info Tag revision + VBR method */
202  avio_r8(s->pb);
203 
204  /* Lowpass filter value */
205  avio_r8(s->pb);
206 
207  /* ReplayGain peak */
208  v = avio_rb32(s->pb);
209  peak = av_rescale(v, 100000, 1 << 23);
210 
211  /* Radio ReplayGain */
212  v = avio_rb16(s->pb);
213 
214  if (MIDDLE_BITS(v, 13, 15) == 1) {
215  r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
216 
217  if (v & (1 << 9))
218  r_gain *= -1;
219  }
220 
221  /* Audiophile ReplayGain */
222  v = avio_rb16(s->pb);
223 
224  if (MIDDLE_BITS(v, 13, 15) == 2) {
225  a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
226 
227  if (v & (1 << 9))
228  a_gain *= -1;
229  }
230 
231  /* Encoding flags + ATH Type */
232  avio_r8(s->pb);
233 
234  /* if ABR {specified bitrate} else {minimal bitrate} */
235  avio_r8(s->pb);
236 
237  /* Encoder delays */
238  v= avio_rb24(s->pb);
239  if(AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
240  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
241  || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
242  ) {
243 
244  mp3->start_pad = v>>12;
245  mp3-> end_pad = v&4095;
246  st->start_skip_samples = mp3->start_pad + 528 + 1;
247  if (mp3->frames) {
248  st->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
249  st->last_discard_sample = mp3->frames * (int64_t)spf;
250  }
251  if (!st->start_time)
253  (AVRational){1, c->sample_rate},
254  st->time_base);
255  av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
256  }
257 
258  /* Misc */
259  avio_r8(s->pb);
260 
261  /* MP3 gain */
262  avio_r8(s->pb);
263 
264  /* Preset and surround info */
265  avio_rb16(s->pb);
266 
267  /* Music length */
268  avio_rb32(s->pb);
269 
270  /* Music CRC */
271  avio_rb16(s->pb);
272 
273  /* Info Tag CRC */
274  crc = ffio_get_checksum(s->pb);
275  v = avio_rb16(s->pb);
276 
277  if (v == crc) {
278  ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
279  av_dict_set(&st->metadata, "encoder", version, 0);
280  }
281 }
282 
283 static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
284 {
285  uint32_t v;
286  MP3DecContext *mp3 = s->priv_data;
287 
288  /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
289  avio_seek(s->pb, base + 4 + 32, SEEK_SET);
290  v = avio_rb32(s->pb);
291  if (v == MKBETAG('V', 'B', 'R', 'I')) {
292  /* Check tag version */
293  if (avio_rb16(s->pb) == 1) {
294  /* skip delay and quality */
295  avio_skip(s->pb, 4);
296  mp3->header_filesize = avio_rb32(s->pb);
297  mp3->frames = avio_rb32(s->pb);
298  }
299  }
300 }
301 
302 /**
303  * Try to find Xing/Info/VBRI tags and compute duration from info therein
304  */
306 {
307  uint32_t v, spf;
309  int vbrtag_size = 0;
310  MP3DecContext *mp3 = s->priv_data;
311  int ret;
312 
314 
315  v = avio_rb32(s->pb);
316 
317  ret = avpriv_mpegaudio_decode_header(&c, v);
318  if (ret < 0)
319  return ret;
320  else if (ret == 0)
321  vbrtag_size = c.frame_size;
322  if(c.layer != 3)
323  return -1;
324 
325  spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
326 
327  mp3->frames = 0;
328  mp3->header_filesize = 0;
329 
330  mp3_parse_info_tag(s, st, &c, spf);
331  mp3_parse_vbri_tag(s, st, base);
332 
333  if (!mp3->frames && !mp3->header_filesize)
334  return -1;
335 
336  /* Skip the vbr tag frame */
337  avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
338 
339  if (mp3->frames)
340  st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
341  st->time_base);
342  if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
343  st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
344 
345  return 0;
346 }
347 
349 {
350  MP3DecContext *mp3 = s->priv_data;
351  AVStream *st;
352  int64_t off;
353  int ret;
354  int i;
355 
356  s->metadata = s->internal->id3v2_meta;
357  s->internal->id3v2_meta = NULL;
358 
359  st = avformat_new_stream(s, NULL);
360  if (!st)
361  return AVERROR(ENOMEM);
362 
366  st->start_time = 0;
367 
368  // lcm of all mp3 sample rates
369  avpriv_set_pts_info(st, 64, 1, 14112000);
370 
371  s->pb->maxsize = -1;
372  off = avio_tell(s->pb);
373 
375  ff_id3v1_read(s);
376 
378  mp3->filesize = avio_size(s->pb);
379 
380  if (mp3_parse_vbr_tags(s, st, off) < 0)
381  avio_seek(s->pb, off, SEEK_SET);
382 
383  ret = ff_replaygain_export(st, s->metadata);
384  if (ret < 0)
385  return ret;
386 
387  off = avio_tell(s->pb);
388  for (i = 0; i < 64 * 1024; i++) {
389  uint32_t header, header2;
390  int frame_size;
391  if (!(i&1023))
392  ffio_ensure_seekback(s->pb, i + 1024 + 4);
393  frame_size = check(s->pb, off + i, &header);
394  if (frame_size > 0) {
395  ret = avio_seek(s->pb, off, SEEK_SET);
396  if (ret < 0)
397  return ret;
398  ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
399  ret = check(s->pb, off + i + frame_size, &header2);
400  if (ret >= 0 &&
401  (header & SAME_HEADER_MASK) == (header2 & SAME_HEADER_MASK))
402  {
403  av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
404  ret = avio_seek(s->pb, off + i, SEEK_SET);
405  if (ret < 0)
406  return ret;
407  break;
408  } else if (ret == CHECK_SEEK_FAILED) {
409  av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
410  return AVERROR(EINVAL);
411  }
412  } else if (frame_size == CHECK_SEEK_FAILED) {
413  av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
414  return AVERROR(EINVAL);
415  }
416  ret = avio_seek(s->pb, off, SEEK_SET);
417  if (ret < 0)
418  return ret;
419  }
420 
421  // the seek index is relative to the end of the xing vbr headers
422  for (i = 0; i < st->nb_index_entries; i++)
423  st->index_entries[i].pos += avio_tell(s->pb);
424 
425  /* the parameters will be extracted from the compressed bitstream */
426  return 0;
427 }
428 
429 #define MP3_PACKET_SIZE 1024
430 
432 {
433  MP3DecContext *mp3 = s->priv_data;
434  int ret, size;
435  int64_t pos;
436 
437  size= MP3_PACKET_SIZE;
438  pos = avio_tell(s->pb);
439  if(mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
440  size= FFMIN(size, mp3->filesize - pos);
441 
442  ret= av_get_packet(s->pb, pkt, size);
443  if (ret <= 0) {
444  if(ret<0)
445  return ret;
446  return AVERROR_EOF;
447  }
448 
449  pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
450  pkt->stream_index = 0;
451 
452  return ret;
453 }
454 
455 #define SEEK_WINDOW 4096
456 
457 static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
458 {
459  int64_t ret = avio_seek(pb, pos, SEEK_SET);
460  uint8_t header_buf[4];
461  unsigned header;
462  MPADecodeHeader sd;
463  if (ret < 0)
464  return CHECK_SEEK_FAILED;
465 
466  ret = avio_read(pb, &header_buf[0], 4);
467  /* We should always find four bytes for a valid mpa header. */
468  if (ret < 4)
469  return CHECK_SEEK_FAILED;
470 
471  header = AV_RB32(&header_buf[0]);
472  if (ff_mpa_check_header(header) < 0)
473  return CHECK_WRONG_HEADER;
474  if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
475  return CHECK_WRONG_HEADER;
476 
477  if (ret_header)
478  *ret_header = header;
479  return sd.frame_size;
480 }
481 
482 static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
483 {
484  int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
485  int64_t best_pos;
486  int best_score, i, j;
487  int64_t ret;
488 
489  avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
490  ret = avio_seek(s->pb, target_pos, SEEK_SET);
491  if (ret < 0)
492  return ret;
493 
494 #define MIN_VALID 3
495  best_pos = target_pos;
496  best_score = 999;
497  for(i=0; i<SEEK_WINDOW; i++) {
498  int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
499  int64_t candidate = -1;
500  int score = 999;
501 
502  if (pos < 0)
503  continue;
504 
505  for(j=0; j<MIN_VALID; j++) {
506  ret = check(s->pb, pos, NULL);
507  if(ret < 0) {
508  if (ret == CHECK_WRONG_HEADER) {
509  break;
510  } else if (ret == CHECK_SEEK_FAILED) {
511  av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
512  return AVERROR(EINVAL);
513  }
514  }
515  if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
516  candidate = pos;
517  score = FFABS(MIN_VALID/2-j);
518  }
519  pos += ret;
520  }
521  if (best_score > score && j == MIN_VALID) {
522  best_pos = candidate;
523  best_score = score;
524  if(score == 0)
525  break;
526  }
527  }
528 
529  return avio_seek(s->pb, best_pos, SEEK_SET);
530 }
531 
532 static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
533  int flags)
534 {
535  MP3DecContext *mp3 = s->priv_data;
536  AVIndexEntry *ie, ie1;
537  AVStream *st = s->streams[0];
538  int64_t best_pos;
539  int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
540  int64_t filesize = mp3->header_filesize;
541 
542  if (filesize <= 0) {
543  int64_t size = avio_size(s->pb);
544  if (size > 0 && size > s->internal->data_offset)
545  filesize = size - s->internal->data_offset;
546  }
547 
548  if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
549  int64_t ret = av_index_search_timestamp(st, timestamp, flags);
550 
551  // NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
552  // for bigger files.
553  av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
554 
555  if (ret < 0)
556  return ret;
557 
558  ie = &st->index_entries[ret];
559  } else if (fast_seek && st->duration > 0 && filesize > 0) {
560  if (!mp3->is_cbr)
561  av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
562 
563  ie = &ie1;
564  timestamp = av_clip64(timestamp, 0, st->duration);
565  ie->timestamp = timestamp;
566  ie->pos = av_rescale(timestamp, filesize, st->duration) + s->internal->data_offset;
567  } else {
568  return -1; // generic index code
569  }
570 
571  best_pos = mp3_sync(s, ie->pos, flags);
572  if (best_pos < 0)
573  return best_pos;
574 
575  if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
576  int frame_duration = av_rescale(st->duration, 1, mp3->frames);
577  ie1.timestamp = frame_duration * av_rescale(best_pos - s->internal->data_offset, mp3->frames, mp3->header_filesize);
578  }
579 
580  ff_update_cur_dts(s, st, ie->timestamp);
581  return 0;
582 }
583 
584 static const AVOption options[] = {
585  { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
586  { NULL },
587 };
588 
589 static const AVClass demuxer_class = {
590  .class_name = "mp3",
591  .item_name = av_default_item_name,
592  .option = options,
593  .version = LIBAVUTIL_VERSION_INT,
594  .category = AV_CLASS_CATEGORY_DEMUXER,
595 };
596 
598  .name = "mp3",
599  .long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
600  .read_probe = mp3_read_probe,
601  .read_header = mp3_read_header,
602  .read_packet = mp3_read_packet,
603  .read_seek = mp3_seek,
604  .priv_data_size = sizeof(MP3DecContext),
606  .extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
607  .priv_class = &demuxer_class,
608 };
#define AVSEEK_FLAG_BACKWARD
Definition: avformat.h:2511
#define NULL
Definition: coverity.c:32
AVDictionary * id3v2_meta
ID3v2 tag useful for MP3 demuxing.
Definition: internal.h:141
Bytestream IO Context.
Definition: avio.h:161
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:336
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:2039
int64_t start_skip_samples
If not 0, the number of samples that should be skipped from the start of the stream (the samples are ...
Definition: avformat.h:1158
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4882
int64_t pos
Definition: avformat.h:810
int64_t data_offset
offset of the first packet
Definition: internal.h:82
int64_t first_discard_sample
If not 0, the first audio sample that should be discarded from the stream.
Definition: avformat.h:1166
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3953
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:235
#define ID3v2_DEFAULT_MAGIC
Default magic bytes for ID3v2 header: "ID3".
Definition: id3v2.h:35
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: avformat.h:1110
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1811
static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
Definition: mp3dec.c:120
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:331
int version
Definition: avisynth_c.h:858
static AVPacket pkt
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:786
#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:55
if it could not because there are no more frames
uint8_t base
Definition: vp3data.h:202
Format I/O context.
Definition: avformat.h:1358
void ff_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp)
Update cur_dts of all streams based on the given timestamp and AVStream.
Definition: utils.c:1953
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:60
Public dictionary API.
static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mp3dec.c:431
uint8_t
int usetoc
Definition: mp3dec.c:54
#define XING_FLAG_SIZE
Definition: mp3dec.c:39
float delta
AVOptions.
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:801
static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: mp3dec.c:532
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
enum AVStreamParseType need_parsing
Definition: avformat.h:1099
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4455
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:87
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
int64_t duration
Definition: movenc.c:63
Public header for CRC hash function implementation.
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1489
int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header)
static const uint8_t xing_offtbl[2][2]
Definition: mp3enc.c:126
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:192
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:310
ptrdiff_t size
Definition: opengl_enc.c:100
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static const uint8_t header[24]
Definition: sdr2.c:67
int ff_replaygain_export(AVStream *st, AVDictionary *metadata)
Parse replaygain tags and export them as per-stream side data.
Definition: replaygain.c:91
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:804
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:648
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3982
int64_t filesize
Definition: mp3dec.c:50
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:142
#define AVINDEX_KEYFRAME
Definition: avformat.h:817
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:260
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1598
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2148
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:811
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
static int mp3_read_header(AVFormatContext *s)
Definition: mp3dec.c:348
#define SAME_HEADER_MASK
Definition: mp3dec.c:45
#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:565
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3949
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:1483
static int mp3_read_probe(const AVProbeData *p)
Definition: mp3dec.c:69
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:639
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:455
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:627
#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:794
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:429
#define FFMIN(a, b)
Definition: common.h:96
static int check(AVIOContext *pb, int64_t pos, uint32_t *header)
Definition: mp3dec.c:457
int end_pad
Definition: mp3dec.c:53
static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st, MPADecodeHeader *c, uint32_t spf)
Definition: mp3dec.c:145
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:482
#define s(width, name)
Definition: cbs_vp9.c:257
int xing_toc
Definition: mp3dec.c:51
AVDictionary * metadata
Definition: avformat.h:945
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:613
static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
Definition: mp3dec.c:283
#define MIN_VALID
Stream structure.
Definition: avformat.h:881
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
int frame_size
Definition: mxfenc.c:2216
Libavcodec external API header.
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
#define XING_FLAG_FRAMES
Definition: mp3dec.c:38
void * buf
Definition: avisynth_c.h:766
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:70
int nb_index_entries
Definition: avformat.h:1112
Describe the class of an AVClass context structure.
Definition: log.h:67
static const AVOption options[]
Definition: mp3dec.c:584
#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:619
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define flags(name, subs,...)
Definition: cbs_av1.c:561
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:1052
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:930
MPEG Audio header decoder.
int is_cbr
Definition: mp3dec.c:57
Main libavformat public API header.
unsigned header_filesize
Definition: mp3dec.c:56
static const AVClass demuxer_class
Definition: mp3dec.c:589
int ff_id3v2_match(const uint8_t *buf, const char *magic)
Detect ID3v2 Header.
Definition: id3v2.c:143
int ff_replaygain_export_raw(AVStream *st, int32_t tg, uint32_t tp, int32_t ag, uint32_t ap)
Export already decoded replaygain values as per-stream side data.
Definition: replaygain.c:70
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:920
AVInputFormat ff_mp3_demuxer
Definition: mp3dec.c:597
#define AV_PKT_FLAG_CORRUPT
The packet content is corrupted.
Definition: avcodec.h:1510
#define MKBETAG(a, b, c, d)
Definition: common.h:367
#define XING_FLAG_TOC
Definition: mp3dec.c:40
#define MIDDLE_BITS(k, m, n)
#define AVFMT_FLAG_FAST_SEEK
Enable fast, but inaccurate seeks for some formats.
Definition: avformat.h:1515
int ff_id3v2_tag_len(const uint8_t *buf)
Get the length of an ID3v2 tag.
Definition: id3v2.c:156
void * priv_data
Format private data.
Definition: avformat.h:1386
#define XING_TOC_COUNT
Definition: mp3dec.c:43
static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
Try to find Xing/Info/VBRI tags and compute duration from info therein.
Definition: mp3dec.c:305
#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:52
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
static int64_t fsize(FILE *f)
Definition: audiomatch.c:28
int stream_index
Definition: avcodec.h:1479
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:910
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
float min
This structure stores compressed data.
Definition: avcodec.h:1454
int64_t last_discard_sample
The sample after last sample that is intended to be discarded after first_discard_sample.
Definition: avformat.h:1173