2 * MP3 muxer and demuxer
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
23 #include "libavutil/avstring.h"
28 #if CONFIG_MP3_DEMUXER
30 #include "libavcodec/mpegaudio.h"
31 #include "libavcodec/mpegaudiodecheader.h"
35 static int mp3_read_probe(AVProbeData *p)
37 int max_frames, first_frames = 0;
38 int fsize, frames, sample_rate;
40 uint8_t *buf, *buf0, *buf2, *end;
44 if(ff_id3v2_match(buf0)) {
45 buf0 += ff_id3v2_tag_len(buf0);
50 end = p->buf + p->buf_size - sizeof(uint32_t);
52 for(; buf < end; buf= buf2+1) {
55 for(frames = 0; buf2 < end; frames++) {
56 header = AV_RB32(buf2);
57 fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
62 max_frames = FFMAX(max_frames, frames);
66 // keep this in sync with ac3 probe, both need to avoid
67 // issues with MPEG-files!
68 if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
69 else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
70 else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
71 else if(buf0!=p->buf) return AVPROBE_SCORE_MAX/4-1;
72 else if(max_frames>=1) return 1;
74 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
78 * Try to find Xing/Info/VBRI tags and compute duration from info therein
80 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
83 int frames = -1; /* Total number of frames in file */
84 const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
89 if(ff_mpa_check_header(v) < 0)
92 if (ff_mpegaudio_decode_header(&c, v) == 0)
93 vbrtag_size = c.frame_size;
97 /* Check for Xing / Info tag */
98 url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
100 if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
103 frames = get_be32(s->pb);
106 /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
107 url_fseek(s->pb, base + 4 + 32, SEEK_SET);
109 if(v == MKBETAG('V', 'B', 'R', 'I')) {
110 /* Check tag version */
111 if(get_be16(s->pb) == 1) {
112 /* skip delay, quality and total bytes */
113 url_fseek(s->pb, 8, SEEK_CUR);
114 frames = get_be32(s->pb);
121 /* Skip the vbr tag frame */
122 url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
124 spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
125 st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
130 static int mp3_read_header(AVFormatContext *s,
131 AVFormatParameters *ap)
136 st = av_new_stream(s, 0);
138 return AVERROR(ENOMEM);
140 st->codec->codec_type = CODEC_TYPE_AUDIO;
141 st->codec->codec_id = CODEC_ID_MP3;
142 st->need_parsing = AVSTREAM_PARSE_FULL;
148 off = url_ftell(s->pb);
149 if (mp3_parse_vbr_tags(s, st, off) < 0)
150 url_fseek(s->pb, off, SEEK_SET);
152 /* the parameters will be extracted from the compressed bitstream */
156 #define MP3_PACKET_SIZE 1024
158 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
161 // AVStream *st = s->streams[0];
163 size= MP3_PACKET_SIZE;
165 ret= av_get_packet(s->pb, pkt, size);
167 pkt->stream_index = 0;
171 /* note: we need to modify the packet size here to handle the last
177 AVInputFormat mp3_demuxer = {
179 NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
184 .flags= AVFMT_GENERIC_INDEX,
185 .extensions = "mp2,mp3,m2a", /* XXX: use probe */
189 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
190 static int id3v1_set_string(AVFormatContext *s, const char *key,
191 uint8_t *buf, int buf_size)
194 if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
195 strncpy(buf, tag->value, buf_size);
199 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
204 memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
208 count += id3v1_set_string(s, "title", buf + 3, 30);
209 count += id3v1_set_string(s, "author", buf + 33, 30);
210 count += id3v1_set_string(s, "album", buf + 63, 30);
211 count += id3v1_set_string(s, "year", buf + 93, 4);
212 count += id3v1_set_string(s, "comment", buf + 97, 30);
213 if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
215 buf[126] = atoi(tag->value);
218 buf[127] = 0xFF; /* default to unknown genre */
219 if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
220 for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
221 if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
233 static void id3v2_put_size(AVFormatContext *s, int size)
235 put_byte(s->pb, size >> 21 & 0x7f);
236 put_byte(s->pb, size >> 14 & 0x7f);
237 put_byte(s->pb, size >> 7 & 0x7f);
238 put_byte(s->pb, size & 0x7f);
241 static void id3v2_put_ttag(AVFormatContext *s, const char *string, uint32_t tag)
243 int len = strlen(string);
244 put_be32(s->pb, tag);
245 id3v2_put_size(s, len + 1);
247 put_byte(s->pb, 3); /* UTF-8 */
248 put_buffer(s->pb, string, len);
253 * Write an ID3v2.4 header at beginning of stream
256 static int mp3_write_header(struct AVFormatContext *s)
258 AVMetadataTag *title, *author, *album, *genre, *copyright, *track, *year;
261 title = av_metadata_get(s->metadata, "title", NULL, 0);
262 author = av_metadata_get(s->metadata, "author", NULL, 0);
263 album = av_metadata_get(s->metadata, "album", NULL, 0);
264 genre = av_metadata_get(s->metadata, "genre", NULL, 0);
265 copyright = av_metadata_get(s->metadata, "copyright", NULL, 0);
266 track = av_metadata_get(s->metadata, "track", NULL, 0);
267 year = av_metadata_get(s->metadata, "year", NULL, 0);
269 if(title) totlen += 11 + strlen(title->value);
270 if(author) totlen += 11 + strlen(author->value);
271 if(album) totlen += 11 + strlen(album->value);
272 if(genre) totlen += 11 + strlen(genre->value);
273 if(copyright) totlen += 11 + strlen(copyright->value);
274 if(track) totlen += 11 + strlen(track->value);
275 if(year) totlen += 11 + strlen(year->value);
276 if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
277 totlen += strlen(LIBAVFORMAT_IDENT) + 11;
282 put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
284 put_byte(s->pb, 0); /* flags */
286 id3v2_put_size(s, totlen);
288 if(title) id3v2_put_ttag(s, title->value, MKBETAG('T', 'I', 'T', '2'));
289 if(author) id3v2_put_ttag(s, author->value, MKBETAG('T', 'P', 'E', '1'));
290 if(album) id3v2_put_ttag(s, album->value, MKBETAG('T', 'A', 'L', 'B'));
291 if(genre) id3v2_put_ttag(s, genre->value, MKBETAG('T', 'C', 'O', 'N'));
292 if(copyright) id3v2_put_ttag(s, copyright->value, MKBETAG('T', 'C', 'O', 'P'));
293 if(track) id3v2_put_ttag(s, track->value, MKBETAG('T', 'R', 'C', 'K'));
294 if(year) id3v2_put_ttag(s, year->value, MKBETAG('T', 'Y', 'E', 'R'));
295 if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
296 id3v2_put_ttag(s, LIBAVFORMAT_IDENT, MKBETAG('T', 'E', 'N', 'C'));
300 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
302 put_buffer(s->pb, pkt->data, pkt->size);
303 put_flush_packet(s->pb);
307 static int mp3_write_trailer(struct AVFormatContext *s)
309 uint8_t buf[ID3v1_TAG_SIZE];
311 /* write the id3v1 tag */
312 if (id3v1_create_tag(s, buf) > 0) {
313 put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
314 put_flush_packet(s->pb);
318 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
321 AVOutputFormat mp2_muxer = {
323 NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
335 AVOutputFormat mp3_muxer = {
337 NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
346 .metadata_conv = ff_id3v2_metadata_conv,