3 * Copyright (c) 2003 Fabrice Bellard
5 * This file is part of FFmpeg.
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.
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.
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
22 #include "libavutil/opt.h"
23 #include "libavutil/avstring.h"
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/dict.h"
26 #include "libavutil/mathematics.h"
31 #include "replaygain.h"
33 #include "libavcodec/mpegaudiodecheader.h"
35 #define XING_FLAG_FRAMES 0x01
36 #define XING_FLAG_SIZE 0x02
37 #define XING_FLAG_TOC 0x04
39 #define XING_TOC_COUNT 100
48 unsigned frames; /* Total number of frames in file */
49 unsigned header_filesize; /* Total number of bytes in the stream */
55 static int mp3_read_probe(AVProbeData *p)
57 int max_frames, first_frames = 0;
58 int fsize, frames, sample_rate;
60 const uint8_t *buf, *buf0, *buf2, *end;
64 end = p->buf + p->buf_size - sizeof(uint32_t);
65 while(buf0 < end && !*buf0)
71 for(; buf < end; buf= buf2+1) {
73 if(ff_mpa_check_header(AV_RB32(buf2)))
76 for(frames = 0; buf2 < end; frames++) {
77 header = AV_RB32(buf2);
78 fsize = avpriv_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
83 max_frames = FFMAX(max_frames, frames);
87 // keep this in sync with ac3 probe, both need to avoid
88 // issues with MPEG-files!
89 if (first_frames>=4) return AVPROBE_SCORE_EXTENSION + 1;
90 else if(max_frames>200)return AVPROBE_SCORE_EXTENSION;
91 else if(max_frames>=4) return AVPROBE_SCORE_EXTENSION / 2;
92 else if(ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
93 return p->buf_size < PROBE_BUF_MAX ? AVPROBE_SCORE_EXTENSION / 4 : AVPROBE_SCORE_EXTENSION - 2;
94 else if(max_frames>=1) return 1;
96 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
99 static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
102 MP3DecContext *mp3 = s->priv_data;
103 int fill_index = mp3->usetoc && duration > 0;
106 !(filesize = avio_size(s->pb))) {
107 av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
111 for (i = 0; i < XING_TOC_COUNT; i++) {
112 uint8_t b = avio_r8(s->pb);
114 av_add_index_entry(s->streams[0],
115 av_rescale(b, filesize, 256),
116 av_rescale(i, duration, XING_TOC_COUNT),
117 0, 0, AVINDEX_KEYFRAME);
124 static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
125 MPADecodeHeader *c, uint32_t spf)
128 MP3DecContext *mp3 = s->priv_data;
129 static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
131 /* Check for Xing / Info tag */
132 avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
133 v = avio_rb32(s->pb);
134 mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
135 if (v == MKBETAG('X', 'i', 'n', 'g') || mp3->is_cbr) {
136 v = avio_rb32(s->pb);
137 if (v & XING_FLAG_FRAMES)
138 mp3->frames = avio_rb32(s->pb);
139 if (v & XING_FLAG_SIZE)
140 mp3->header_filesize = avio_rb32(s->pb);
141 if (v & XING_FLAG_TOC)
142 read_xing_toc(s, mp3->header_filesize,
143 av_rescale_q(mp3->frames,
144 (AVRational){spf, c->sample_rate},
149 v = avio_rb32(s->pb);
150 if(v == MKBETAG('L', 'A', 'M', 'E') || v == MKBETAG('L', 'a', 'v', 'f')) {
151 avio_skip(s->pb, 21-4);
153 mp3->start_pad = v>>12;
154 mp3-> end_pad = v&4095;
155 st->skip_samples = mp3->start_pad + 528 + 1;
157 st->start_time = av_rescale_q(st->skip_samples,
158 (AVRational){1, c->sample_rate},
160 av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad);
165 static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
168 MP3DecContext *mp3 = s->priv_data;
170 /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
171 avio_seek(s->pb, base + 4 + 32, SEEK_SET);
172 v = avio_rb32(s->pb);
173 if (v == MKBETAG('V', 'B', 'R', 'I')) {
174 /* Check tag version */
175 if (avio_rb16(s->pb) == 1) {
176 /* skip delay and quality */
178 mp3->header_filesize = avio_rb32(s->pb);
179 mp3->frames = avio_rb32(s->pb);
185 * Try to find Xing/Info/VBRI tags and compute duration from info therein
187 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
192 MP3DecContext *mp3 = s->priv_data;
194 v = avio_rb32(s->pb);
195 if(ff_mpa_check_header(v) < 0)
198 if (avpriv_mpegaudio_decode_header(&c, v) == 0)
199 vbrtag_size = c.frame_size;
203 spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
206 mp3->header_filesize = 0;
208 mp3_parse_info_tag(s, st, &c, spf);
209 mp3_parse_vbri_tag(s, st, base);
211 if (!mp3->frames && !mp3->header_filesize)
214 /* Skip the vbr tag frame */
215 avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
218 st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
220 if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
221 st->codec->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
226 static int mp3_read_header(AVFormatContext *s)
228 MP3DecContext *mp3 = s->priv_data;
233 st = avformat_new_stream(s, NULL);
235 return AVERROR(ENOMEM);
237 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
238 st->codec->codec_id = AV_CODEC_ID_MP3;
239 st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
242 // lcm of all mp3 sample rates
243 avpriv_set_pts_info(st, 64, 1, 14112000);
246 off = avio_tell(s->pb);
248 if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
252 mp3->filesize = avio_size(s->pb);
254 if (mp3_parse_vbr_tags(s, st, off) < 0)
255 avio_seek(s->pb, off, SEEK_SET);
257 ret = ff_replaygain_export(st, s->metadata);
261 /* the parameters will be extracted from the compressed bitstream */
265 #define MP3_PACKET_SIZE 1024
267 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
269 MP3DecContext *mp3 = s->priv_data;
273 size= MP3_PACKET_SIZE;
274 pos = avio_tell(s->pb);
275 if(mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
276 size= FFMIN(size, mp3->filesize - pos);
278 ret= av_get_packet(s->pb, pkt, size);
285 pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
286 pkt->stream_index = 0;
288 if (ret >= ID3v1_TAG_SIZE &&
289 memcmp(&pkt->data[ret - ID3v1_TAG_SIZE], "TAG", 3) == 0)
290 ret -= ID3v1_TAG_SIZE;
292 /* note: we need to modify the packet size here to handle the last
298 static int check(AVFormatContext *s, int64_t pos)
300 int64_t ret = avio_seek(s->pb, pos, SEEK_SET);
305 header = avio_rb32(s->pb);
306 if (ff_mpa_check_header(header) < 0)
308 if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
310 return sd.frame_size;
313 static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
316 MP3DecContext *mp3 = s->priv_data;
317 AVIndexEntry *ie, ie1;
318 AVStream *st = s->streams[0];
319 int64_t ret = av_index_search_timestamp(st, timestamp, flags);
321 int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
323 if (mp3->is_cbr && st->duration > 0 && mp3->header_filesize > s->data_offset) {
324 int64_t filesize = avio_size(s->pb);
326 if (filesize <= s->data_offset)
327 filesize = mp3->header_filesize;
328 filesize -= s->data_offset;
329 duration = av_rescale(st->duration, filesize, mp3->header_filesize - s->data_offset);
331 timestamp = av_clip64(timestamp, 0, duration);
332 ie->timestamp = timestamp;
333 ie->pos = av_rescale(timestamp, filesize, duration) + s->data_offset;
334 } else if (mp3->xing_toc) {
338 ie = &st->index_entries[ret];
340 st->skip_samples = timestamp <= 0 ? mp3->start_pad + 528 + 1 : 0;
346 avio_seek(s->pb, FFMAX(ie->pos - 4096, 0), SEEK_SET);
347 ret = avio_seek(s->pb, ie->pos, SEEK_SET);
352 for(i=0; i<4096; i++) {
353 int64_t pos = ie->pos + i*dir;
354 for(j=0; j<MIN_VALID; j++) {
366 ret = avio_seek(s->pb, ie->pos + i*dir, SEEK_SET);
369 ff_update_cur_dts(s, st, ie->timestamp);
370 st->skip_samples = ie->timestamp <= 0 ? mp3->start_pad + 528 + 1 : 0;
374 static const AVOption options[] = {
375 { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, AV_OPT_FLAG_DECODING_PARAM},
379 static const AVClass demuxer_class = {
381 .item_name = av_default_item_name,
383 .version = LIBAVUTIL_VERSION_INT,
384 .category = AV_CLASS_CATEGORY_DEMUXER,
387 AVInputFormat ff_mp3_demuxer = {
389 .long_name = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
390 .read_probe = mp3_read_probe,
391 .read_header = mp3_read_header,
392 .read_packet = mp3_read_packet,
393 .read_seek = mp3_seek,
394 .priv_data_size = sizeof(MP3DecContext),
395 .flags = AVFMT_GENERIC_INDEX,
396 .extensions = "mp2,mp3,m2a,mpa", /* XXX: use probe */
397 .priv_class = &demuxer_class,