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 if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
67 else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
68 else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
69 else if(buf0!=p->buf) return AVPROBE_SCORE_MAX/4-1;
70 else if(max_frames>=1) return 1;
72 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
76 * Try to find Xing/Info/VBRI tags and compute duration from info therein
78 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
81 int frames = -1; /* Total number of frames in file */
82 const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
87 if(ff_mpa_check_header(v) < 0)
90 if (ff_mpegaudio_decode_header(&c, v) == 0)
91 vbrtag_size = c.frame_size;
95 /* Check for Xing / Info tag */
96 url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
98 if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
101 frames = get_be32(s->pb);
104 /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
105 url_fseek(s->pb, base + 4 + 32, SEEK_SET);
107 if(v == MKBETAG('V', 'B', 'R', 'I')) {
108 /* Check tag version */
109 if(get_be16(s->pb) == 1) {
110 /* skip delay, quality and total bytes */
111 url_fseek(s->pb, 8, SEEK_CUR);
112 frames = get_be32(s->pb);
119 /* Skip the vbr tag frame */
120 url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
122 spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
123 st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
128 static int mp3_read_header(AVFormatContext *s,
129 AVFormatParameters *ap)
134 st = av_new_stream(s, 0);
136 return AVERROR(ENOMEM);
138 st->codec->codec_type = CODEC_TYPE_AUDIO;
139 st->codec->codec_id = CODEC_ID_MP3;
140 st->need_parsing = AVSTREAM_PARSE_FULL;
146 off = url_ftell(s->pb);
147 if (mp3_parse_vbr_tags(s, st, off) < 0)
148 url_fseek(s->pb, off, SEEK_SET);
150 /* the parameters will be extracted from the compressed bitstream */
154 #define MP3_PACKET_SIZE 1024
156 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
159 // AVStream *st = s->streams[0];
161 size= MP3_PACKET_SIZE;
163 ret= av_get_packet(s->pb, pkt, size);
165 pkt->stream_index = 0;
169 /* note: we need to modify the packet size here to handle the last
175 AVInputFormat mp3_demuxer = {
177 NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
182 .flags= AVFMT_GENERIC_INDEX,
183 .extensions = "mp2,mp3,m2a", /* XXX: use probe */
187 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
188 static int id3v1_set_string(AVFormatContext *s, const char *key,
189 uint8_t *buf, int buf_size)
192 if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
193 strncpy(buf, tag->value, buf_size);
197 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
202 memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
206 count += id3v1_set_string(s, "title", buf + 3, 30);
207 count += id3v1_set_string(s, "author", buf + 33, 30);
208 count += id3v1_set_string(s, "album", buf + 63, 30);
209 count += id3v1_set_string(s, "year", buf + 93, 4);
210 count += id3v1_set_string(s, "comment", buf + 97, 30);
211 if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
213 buf[126] = atoi(tag->value);
216 buf[127] = 0xFF; /* default to unknown genre */
217 if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
218 for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
219 if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
231 static void id3v2_put_size(AVFormatContext *s, int size)
233 put_byte(s->pb, size >> 21 & 0x7f);
234 put_byte(s->pb, size >> 14 & 0x7f);
235 put_byte(s->pb, size >> 7 & 0x7f);
236 put_byte(s->pb, size & 0x7f);
239 static void id3v2_put_ttag(AVFormatContext *s, const char *string, uint32_t tag)
241 int len = strlen(string);
242 put_be32(s->pb, tag);
243 id3v2_put_size(s, len + 1);
245 put_byte(s->pb, 3); /* UTF-8 */
246 put_buffer(s->pb, string, len);
251 * Write an ID3v2.4 header at beginning of stream
254 static int mp3_write_header(struct AVFormatContext *s)
256 AVMetadataTag *title, *author, *album, *genre, *copyright, *track, *year;
259 title = av_metadata_get(s->metadata, "title", NULL, 0);
260 author = av_metadata_get(s->metadata, "author", NULL, 0);
261 album = av_metadata_get(s->metadata, "album", NULL, 0);
262 genre = av_metadata_get(s->metadata, "genre", NULL, 0);
263 copyright = av_metadata_get(s->metadata, "copyright", NULL, 0);
264 track = av_metadata_get(s->metadata, "track", NULL, 0);
265 year = av_metadata_get(s->metadata, "year", NULL, 0);
267 if(title) totlen += 11 + strlen(title->value);
268 if(author) totlen += 11 + strlen(author->value);
269 if(album) totlen += 11 + strlen(album->value);
270 if(genre) totlen += 11 + strlen(genre->value);
271 if(copyright) totlen += 11 + strlen(copyright->value);
272 if(track) totlen += 11 + strlen(track->value);
273 if(year) totlen += 11 + strlen(year->value);
274 if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
275 totlen += strlen(LIBAVFORMAT_IDENT) + 11;
280 put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
282 put_byte(s->pb, 0); /* flags */
284 id3v2_put_size(s, totlen);
286 if(title) id3v2_put_ttag(s, title->value, MKBETAG('T', 'I', 'T', '2'));
287 if(author) id3v2_put_ttag(s, author->value, MKBETAG('T', 'P', 'E', '1'));
288 if(album) id3v2_put_ttag(s, album->value, MKBETAG('T', 'A', 'L', 'B'));
289 if(genre) id3v2_put_ttag(s, genre->value, MKBETAG('T', 'C', 'O', 'N'));
290 if(copyright) id3v2_put_ttag(s, copyright->value, MKBETAG('T', 'C', 'O', 'P'));
291 if(track) id3v2_put_ttag(s, track->value, MKBETAG('T', 'R', 'C', 'K'));
292 if(year) id3v2_put_ttag(s, year->value, MKBETAG('T', 'Y', 'E', 'R'));
293 if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
294 id3v2_put_ttag(s, LIBAVFORMAT_IDENT, MKBETAG('T', 'E', 'N', 'C'));
298 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
300 put_buffer(s->pb, pkt->data, pkt->size);
301 put_flush_packet(s->pb);
305 static int mp3_write_trailer(struct AVFormatContext *s)
307 uint8_t buf[ID3v1_TAG_SIZE];
309 /* write the id3v1 tag */
310 if (id3v1_create_tag(s, buf) > 0) {
311 put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
312 put_flush_packet(s->pb);
316 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
319 AVOutputFormat mp2_muxer = {
321 NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
333 AVOutputFormat mp3_muxer = {
335 NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
344 .metadata_conv = ff_id3v2_metadata_conv,