FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/mp3dec.c
Date: 2023-12-04 05:51:44
Exec Total Coverage
Lines: 268 310 86.5%
Functions: 10 10 100.0%
Branches: 172 242 71.1%
Line Branch Exec Source
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/intreadwrite.h"
24 #include "libavutil/dict.h"
25 #include "libavutil/mathematics.h"
26 #include "avformat.h"
27 #include "internal.h"
28 #include "avio_internal.h"
29 #include "demux.h"
30 #include "id3v2.h"
31 #include "id3v1.h"
32 #include "replaygain.h"
33
34 #include "libavcodec/codec_id.h"
35 #include "libavcodec/mpegaudiodecheader.h"
36
37 #define XING_FLAG_FRAMES 0x01
38 #define XING_FLAG_SIZE 0x02
39 #define XING_FLAG_TOC 0x04
40 #define XING_FLAC_QSCALE 0x08
41
42 #define XING_TOC_COUNT 100
43
44
45 typedef struct {
46 AVClass *class;
47 int64_t filesize;
48 int xing_toc;
49 int start_pad;
50 int end_pad;
51 int usetoc;
52 unsigned frames; /* Total number of frames in file */
53 unsigned header_filesize; /* Total number of bytes in the stream */
54 int is_cbr;
55 } MP3DecContext;
56
57 enum CheckRet {
58 CHECK_WRONG_HEADER = -1,
59 CHECK_SEEK_FAILED = -2,
60 };
61
62 static int check(AVIOContext *pb, int64_t pos, uint32_t *header);
63
64 /* mp3 read */
65
66 6924 static int mp3_read_probe(const AVProbeData *p)
67 {
68 6924 int max_frames, first_frames = 0;
69 6924 int whole_used = 0;
70 int frames, ret;
71 int framesizes, max_framesizes;
72 uint32_t header;
73 const uint8_t *buf, *buf0, *buf2, *buf3, *end;
74
75 6924 buf0 = p->buf;
76 6924 end = p->buf + p->buf_size - sizeof(uint32_t);
77
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 125033 while (buf0 < end && !*buf0)
78 118109 buf0++;
79
80 6924 max_frames = 0;
81 6924 max_framesizes = 0;
82 6924 buf = buf0;
83
84
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 127856642 for (; buf < end; buf = buf2+1) {
85 127849718 buf2 = buf;
86
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 127879655 for (framesizes = frames = 0; buf2 < end; frames++) {
87 MPADecodeHeader h;
88 127879654 int header_emu = 0;
89 int available;
90
91 127879654 header = AV_RB32(buf2);
92 127879654 ret = avpriv_mpegaudio_decode_header(&h, header);
93
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 127879654 if (ret != 0)
94 127849717 break;
95
96 32016 available = FFMIN(h.frame_size, end - buf2);
97
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 12094456 for (buf3 = buf2 + 4; buf3 < buf2 + available; buf3++) {
98 12062440 uint32_t next_sync = AV_RB32(buf3);
99 12062440 header_emu += (next_sync & MP3_MASK) == (header & MP3_MASK);
100 }
101
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 32016 if (header_emu > 2)
102 1070 break;
103 30946 framesizes += h.frame_size;
104
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 30946 if (available < h.frame_size) {
105 1009 frames++;
106 1009 break;
107 }
108 29937 buf2 += h.frame_size;
109 }
110 127849718 max_frames = FFMAX(max_frames, frames);
111 127849718 max_framesizes = FFMAX(max_framesizes, framesizes);
112
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 127849718 if (buf == buf0) {
113 6920 first_frames= frames;
114
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 6920 if (buf2 == end + sizeof(uint32_t))
115 ✗ whole_used = 1;
116 }
117 }
118 // keep this in sync with ac3 probe, both need to avoid
119 // issues with MPEG-files!
120
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 6924 if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
121
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 6895 else if (max_frames>200 && p->buf_size < 2*max_framesizes)return AVPROBE_SCORE_EXTENSION;
122
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 6895 else if (max_frames>=4 && p->buf_size < 2*max_framesizes) return AVPROBE_SCORE_EXTENSION / 2;
123
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 6888 else if (ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
124
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 21 return p->buf_size < PROBE_BUF_MAX ? AVPROBE_SCORE_EXTENSION / 4 : AVPROBE_SCORE_EXTENSION - 2;
125
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 6867 else if (first_frames > 1 && whole_used) return 5;
126
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 6867 else if (max_frames>=1 && p->buf_size < 10*max_framesizes) return 1;
127 5613 else return 0;
128 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
129 }
130
131 17 static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
132 {
133 int i;
134 17 MP3DecContext *mp3 = s->priv_data;
135 17 int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
136
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 17 int fill_index = (mp3->usetoc || fast_seek) && duration > 0;
137
138
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 17 if (!filesize &&
139 ✗ !(filesize = avio_size(s->pb))) {
140 ✗ av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
141 ✗ fill_index = 0;
142 }
143
144
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 1717 for (i = 0; i < XING_TOC_COUNT; i++) {
145 1700 uint8_t b = avio_r8(s->pb);
146
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 1700 if (fill_index)
147 100 av_add_index_entry(s->streams[0],
148 av_rescale(b, filesize, 256),
149 av_rescale(i, duration, XING_TOC_COUNT),
150 0, 0, AVINDEX_KEYFRAME);
151 }
152
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 17 if (fill_index)
153 1 mp3->xing_toc = 1;
154 17 }
155
156 28 static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
157 MPADecodeHeader *c, uint32_t spf)
158 {
159 #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
160 #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))
161
162 28 FFStream *const sti = ffstream(st);
163 uint16_t crc;
164 uint32_t v;
165
166 char version[10];
167
168 28 uint32_t peak = 0;
169 28 int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
170
171 28 MP3DecContext *mp3 = s->priv_data;
172 static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
173 28 uint64_t fsize = avio_size(s->pb);
174 28 int64_t pos = avio_tell(s->pb);
175
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 28 fsize = fsize >= pos ? fsize - pos : 0;
176
177 /* Check for Xing / Info tag */
178 28 avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
179 28 v = avio_rb32(s->pb);
180 28 mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
181
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 28 if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
182 10 return;
183
184 18 v = avio_rb32(s->pb);
185
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 18 if (v & XING_FLAG_FRAMES)
186 18 mp3->frames = avio_rb32(s->pb);
187
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 18 if (v & XING_FLAG_SIZE)
188 17 mp3->header_filesize = avio_rb32(s->pb);
189
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 18 if (fsize && mp3->header_filesize) {
190 uint64_t min, delta;
191 17 min = FFMIN(fsize, mp3->header_filesize);
192 17 delta = FFMAX(fsize, mp3->header_filesize) - min;
193
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 17 if (fsize > mp3->header_filesize && delta > min >> 4) {
194 ✗ mp3->frames = 0;
195 ✗ av_log(s, AV_LOG_WARNING,
196 "invalid concatenated file detected - using bitrate for duration\n");
197
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 17 } else if (delta > min >> 4) {
198 ✗ av_log(s, AV_LOG_WARNING,
199 "filesize and duration do not match (growing file?)\n");
200 }
201 }
202
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 18 if (v & XING_FLAG_TOC)
203 17 read_xing_toc(s, mp3->header_filesize, av_rescale_q(mp3->frames,
204 17 (AVRational){spf, c->sample_rate},
205 st->time_base));
206 /* VBR quality */
207
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 18 if (v & XING_FLAC_QSCALE)
208 15 avio_rb32(s->pb);
209
210 /* Encoder short version string */
211 18 memset(version, 0, sizeof(version));
212 18 avio_read(s->pb, version, 9);
213
214 /* Info Tag revision + VBR method */
215 18 avio_r8(s->pb);
216
217 /* Lowpass filter value */
218 18 avio_r8(s->pb);
219
220 /* ReplayGain peak */
221 18 v = avio_rb32(s->pb);
222 18 peak = av_rescale(v, 100000, 1 << 23);
223
224 /* Radio ReplayGain */
225 18 v = avio_rb16(s->pb);
226
227
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 18 if (MIDDLE_BITS(v, 13, 15) == 1) {
228 ✗ r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
229
230 ✗ if (v & (1 << 9))
231 ✗ r_gain *= -1;
232 }
233
234 /* Audiophile ReplayGain */
235 18 v = avio_rb16(s->pb);
236
237
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 18 if (MIDDLE_BITS(v, 13, 15) == 2) {
238 ✗ a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
239
240 ✗ if (v & (1 << 9))
241 ✗ a_gain *= -1;
242 }
243
244 /* Encoding flags + ATH Type */
245 18 avio_r8(s->pb);
246
247 /* if ABR {specified bitrate} else {minimal bitrate} */
248 18 avio_r8(s->pb);
249
250 /* Encoder delays */
251 18 v = avio_rb24(s->pb);
252
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 18 if (AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
253
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 8 || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
254
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 1 || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
255 ) {
256
257 17 mp3->start_pad = v>>12;
258 17 mp3-> end_pad = v&4095;
259 17 sti->start_skip_samples = mp3->start_pad + 528 + 1;
260
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 17 if (mp3->frames) {
261 17 sti->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
262 17 sti->last_discard_sample = mp3->frames * (int64_t)spf;
263 }
264
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 17 if (!st->start_time)
265 17 st->start_time = av_rescale_q(sti->start_skip_samples,
266 17 (AVRational){1, c->sample_rate},
267 st->time_base);
268 17 av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
269 }
270
271 /* Misc */
272 18 avio_r8(s->pb);
273
274 /* MP3 gain */
275 18 avio_r8(s->pb);
276
277 /* Preset and surround info */
278 18 avio_rb16(s->pb);
279
280 /* Music length */
281 18 avio_rb32(s->pb);
282
283 /* Music CRC */
284 18 avio_rb16(s->pb);
285
286 /* Info Tag CRC */
287 18 crc = ffio_get_checksum(s->pb);
288 18 v = avio_rb16(s->pb);
289
290
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 18 if (v == crc) {
291 12 ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
292 12 av_dict_set(&st->metadata, "encoder", version, 0);
293 }
294 }
295
296 28 static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
297 {
298 uint32_t v;
299 28 MP3DecContext *mp3 = s->priv_data;
300
301 /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
302 28 avio_seek(s->pb, base + 4 + 32, SEEK_SET);
303 28 v = avio_rb32(s->pb);
304
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 28 if (v == MKBETAG('V', 'B', 'R', 'I')) {
305 /* Check tag version */
306 ✗ if (avio_rb16(s->pb) == 1) {
307 /* skip delay and quality */
308 ✗ avio_skip(s->pb, 4);
309 ✗ mp3->header_filesize = avio_rb32(s->pb);
310 ✗ mp3->frames = avio_rb32(s->pb);
311 }
312 }
313 28 }
314
315 /**
316 * Try to find Xing/Info/VBRI tags and compute duration from info therein
317 */
318 32 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
319 {
320 uint32_t v, spf;
321 MPADecodeHeader c;
322 32 int vbrtag_size = 0;
323 32 MP3DecContext *mp3 = s->priv_data;
324 int ret;
325
326 32 ffio_init_checksum(s->pb, ff_crcA001_update, 0);
327
328 32 v = avio_rb32(s->pb);
329
330 32 ret = avpriv_mpegaudio_decode_header(&c, v);
331
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 32 if (ret < 0)
332 1 return ret;
333
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 31 else if (ret == 0)
334 31 vbrtag_size = c.frame_size;
335
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 31 if (c.layer != 3)
336 3 return -1;
337
338
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 28 spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
339
340 28 mp3->frames = 0;
341 28 mp3->header_filesize = 0;
342
343 28 mp3_parse_info_tag(s, st, &c, spf);
344 28 mp3_parse_vbri_tag(s, st, base);
345
346
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 28 if (!mp3->frames && !mp3->header_filesize)
347 10 return -1;
348
349 /* Skip the vbr tag frame */
350 18 avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
351
352
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 18 if (mp3->frames)
353 18 st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
354 st->time_base);
355
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 18 if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
356 1 st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
357
358 18 return 0;
359 }
360
361 32 static int mp3_read_header(AVFormatContext *s)
362 {
363 32 FFFormatContext *const si = ffformatcontext(s);
364 32 MP3DecContext *mp3 = s->priv_data;
365 AVStream *st;
366 FFStream *sti;
367 int64_t off;
368 int ret;
369 int i;
370
371 32 s->metadata = si->id3v2_meta;
372 32 si->id3v2_meta = NULL;
373
374 32 st = avformat_new_stream(s, NULL);
375
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 32 if (!st)
376 ✗ return AVERROR(ENOMEM);
377 32 sti = ffstream(st);
378
379 32 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
380 32 st->codecpar->codec_id = AV_CODEC_ID_MP3;
381 32 sti->need_parsing = AVSTREAM_PARSE_FULL_RAW;
382 32 st->start_time = 0;
383
384 // lcm of all mp3 sample rates
385 32 avpriv_set_pts_info(st, 64, 1, 14112000);
386
387 32 ffiocontext(s->pb)->maxsize = -1;
388 32 off = avio_tell(s->pb);
389
390
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 32 if (!av_dict_count(s->metadata))
391 13 ff_id3v1_read(s);
392
393
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 32 if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
394 32 mp3->filesize = avio_size(s->pb);
395
396
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 32 if (mp3_parse_vbr_tags(s, st, off) < 0)
397 14 avio_seek(s->pb, off, SEEK_SET);
398
399 32 ret = ff_replaygain_export(st, s->metadata);
400
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 32 if (ret < 0)
401 ✗ return ret;
402
403 32 off = avio_tell(s->pb);
404
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 658 for (i = 0; i < 64 * 1024; i++) {
405 uint32_t header, header2;
406 int frame_size;
407
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 658 if (!(i&1023))
408 32 ffio_ensure_seekback(s->pb, i + 1024 + 4);
409 658 frame_size = check(s->pb, off + i, &header);
410
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 658 if (frame_size > 0) {
411 32 ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
412 32 ret = check(s->pb, off + i + frame_size, &header2);
413
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 32 if (ret >= 0 &&
414
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 32 (header & MP3_MASK) == (header2 & MP3_MASK))
415 {
416 break;
417 ✗ } else if (ret == CHECK_SEEK_FAILED) {
418 ✗ av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
419 ✗ return AVERROR(EINVAL);
420 }
421
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 626 } else if (frame_size == CHECK_SEEK_FAILED) {
422 ✗ av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
423 ✗ return AVERROR(EINVAL);
424 }
425 }
426
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 32 if (i == 64 * 1024) {
427 ✗ off = avio_seek(s->pb, off, SEEK_SET);
428 } else {
429
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 32 av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
430 32 off = avio_seek(s->pb, off + i, SEEK_SET);
431 }
432
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 32 if (off < 0)
433 ✗ return off;
434
435 // the seek index is relative to the end of the xing vbr headers
436
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 132 for (int i = 0; i < sti->nb_index_entries; i++)
437 100 sti->index_entries[i].pos += off;
438
439 /* the parameters will be extracted from the compressed bitstream */
440 32 return 0;
441 }
442
443 #define MP3_PACKET_SIZE 1024
444
445 3141 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
446 {
447 3141 MP3DecContext *mp3 = s->priv_data;
448 int ret, size;
449 int64_t pos;
450
451 3141 size = MP3_PACKET_SIZE;
452 3141 pos = avio_tell(s->pb);
453
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 3141 if (mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
454 3105 size= FFMIN(size, mp3->filesize - pos);
455
456 3141 ret = av_get_packet(s->pb, pkt, size);
457
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 3141 if (ret <= 0) {
458
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 36 if(ret<0)
459 36 return ret;
460 ✗ return AVERROR_EOF;
461 }
462
463 3105 pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
464 3105 pkt->stream_index = 0;
465
466 3105 return ret;
467 }
468
469 #define SEEK_WINDOW 4096
470
471 17660 static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
472 {
473 17660 int64_t ret = avio_seek(pb, pos, SEEK_SET);
474 uint8_t header_buf[4];
475 unsigned header;
476 MPADecodeHeader sd;
477
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 17660 if (ret < 0)
478 ✗ return CHECK_SEEK_FAILED;
479
480 17660 ret = avio_read(pb, &header_buf[0], 4);
481 /* We should always find four bytes for a valid mpa header. */
482
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 17660 if (ret < 4)
483 ✗ return CHECK_SEEK_FAILED;
484
485 17660 header = AV_RB32(&header_buf[0]);
486
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 17660 if (ff_mpa_check_header(header) < 0)
487 17424 return CHECK_WRONG_HEADER;
488
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 236 if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
489 ✗ return CHECK_WRONG_HEADER;
490
491
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 236 if (ret_header)
492 64 *ret_header = header;
493 236 return sd.frame_size;
494 }
495
496 26 static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
497 {
498
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 26 int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
499 int64_t best_pos;
500 int best_score, i, j;
501 int64_t ret;
502
503 26 avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
504 26 ret = avio_seek(s->pb, target_pos, SEEK_SET);
505
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 26 if (ret < 0)
506 ✗ return ret;
507
508 #define MIN_VALID 3
509 26 best_pos = target_pos;
510 26 best_score = 999;
511
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 16850 for (i = 0; i < SEEK_WINDOW; i++) {
512
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 16850 int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
513 16850 int64_t candidate = -1;
514 16850 int score = 999;
515
516
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 16850 if (pos < 0)
517 ✗ continue;
518
519
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 17022 for (j = 0; j < MIN_VALID; j++) {
520 16970 ret = check(s->pb, pos, NULL);
521
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 16970 if (ret < 0) {
522
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 16798 if (ret == CHECK_WRONG_HEADER) {
523 16798 break;
524 ✗ } else if (ret == CHECK_SEEK_FAILED) {
525 ✗ av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
526 ✗ return AVERROR(EINVAL);
527 }
528 }
529
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 172 if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
530 68 candidate = pos;
531
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 68 score = FFABS(MIN_VALID/2-j);
532 }
533 172 pos += ret;
534 }
535
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 16850 if (best_score > score && j == MIN_VALID) {
536 48 best_pos = candidate;
537 48 best_score = score;
538
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 48 if(score == 0)
539 26 break;
540 }
541 }
542
543 26 return avio_seek(s->pb, best_pos, SEEK_SET);
544 }
545
546 128 static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
547 int flags)
548 {
549 128 FFFormatContext *const si = ffformatcontext(s);
550 128 MP3DecContext *mp3 = s->priv_data;
551 AVIndexEntry *ie, ie1;
552 128 AVStream *st = s->streams[0];
553 128 FFStream *const sti = ffstream(st);
554 int64_t best_pos;
555 128 int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
556 128 int64_t filesize = mp3->header_filesize;
557
558
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 128 if (filesize <= 0) {
559 48 int64_t size = avio_size(s->pb);
560
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 48 if (size > 0 && size > si->data_offset)
561 48 filesize = size - si->data_offset;
562 }
563
564
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 128 if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
565 ✗ int64_t ret = av_index_search_timestamp(st, timestamp, flags);
566
567 // NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
568 // for bigger files.
569 ✗ av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
570
571 ✗ if (ret < 0)
572 ✗ return ret;
573
574 ✗ ie = &sti->index_entries[ret];
575
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 128 } else if (fast_seek && st->duration > 0 && filesize > 0) {
576
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 26 if (!mp3->is_cbr)
577 ✗ av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
578
579 26 ie = &ie1;
580 26 timestamp = av_clip64(timestamp, 0, st->duration);
581 26 ie->timestamp = timestamp;
582 26 ie->pos = av_rescale(timestamp, filesize, st->duration) + si->data_offset;
583 } else {
584 102 return -1; // generic index code
585 }
586
587 26 best_pos = mp3_sync(s, ie->pos, flags);
588
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 26 if (best_pos < 0)
589 ✗ return best_pos;
590
591
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 26 if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
592 26 int frame_duration = av_rescale(st->duration, 1, mp3->frames);
593 26 ie1.timestamp = frame_duration * av_rescale(best_pos - si->data_offset, mp3->frames, mp3->header_filesize);
594 }
595
596 26 avpriv_update_cur_dts(s, st, ie->timestamp);
597 26 return 0;
598 }
599
600 static const AVOption options[] = {
601 { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
602 { NULL },
603 };
604
605 static const AVClass demuxer_class = {
606 .class_name = "mp3",
607 .item_name = av_default_item_name,
608 .option = options,
609 .version = LIBAVUTIL_VERSION_INT,
610 .category = AV_CLASS_CATEGORY_DEMUXER,
611 };
612
613 const AVInputFormat ff_mp3_demuxer = {
614 .name = "mp3",
615 .long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
616 .read_probe = mp3_read_probe,
617 .read_header = mp3_read_header,
618 .read_packet = mp3_read_packet,
619 .read_seek = mp3_seek,
620 .priv_data_size = sizeof(MP3DecContext),
621 .flags = AVFMT_GENERIC_INDEX,
622 .extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
623 .priv_class = &demuxer_class,
624 };
625