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"
24 #include "libavutil/intreadwrite.h"
29 #if CONFIG_MP3_DEMUXER
31 #include "libavcodec/mpegaudio.h"
32 #include "libavcodec/mpegaudiodecheader.h"
36 static int mp3_read_probe(AVProbeData *p)
38 int max_frames, first_frames = 0;
39 int fsize, frames, sample_rate;
41 uint8_t *buf, *buf0, *buf2, *end;
45 end = p->buf + p->buf_size - sizeof(uint32_t);
46 while(buf0 < end && !*buf0)
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(max_frames>=1) return 1;
73 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
77 * Try to find Xing/Info/VBRI tags and compute duration from info therein
79 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
82 unsigned frames = 0; /* Total number of frames in file */
83 unsigned size = 0; /* Total number of bytes in the stream */
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);
105 size = get_be32(s->pb);
108 /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
109 url_fseek(s->pb, base + 4 + 32, SEEK_SET);
111 if(v == MKBETAG('V', 'B', 'R', 'I')) {
112 /* Check tag version */
113 if(get_be16(s->pb) == 1) {
114 /* skip delay and quality */
115 url_fseek(s->pb, 4, SEEK_CUR);
116 frames = get_be32(s->pb);
117 size = get_be32(s->pb);
124 /* Skip the vbr tag frame */
125 url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
127 spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
129 st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
132 st->codec->bit_rate = av_rescale(size, 8 * c.sample_rate, frames * (int64_t)spf);
137 static int mp3_read_header(AVFormatContext *s,
138 AVFormatParameters *ap)
143 st = av_new_stream(s, 0);
145 return AVERROR(ENOMEM);
147 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
148 st->codec->codec_id = CODEC_ID_MP3;
149 st->need_parsing = AVSTREAM_PARSE_FULL;
152 // lcm of all mp3 sample rates
153 av_set_pts_info(st, 64, 1, 14112000);
155 off = url_ftell(s->pb);
157 if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))
160 if (mp3_parse_vbr_tags(s, st, off) < 0)
161 url_fseek(s->pb, off, SEEK_SET);
163 /* the parameters will be extracted from the compressed bitstream */
167 #define MP3_PACKET_SIZE 1024
169 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
172 // AVStream *st = s->streams[0];
174 size= MP3_PACKET_SIZE;
176 ret= av_get_packet(s->pb, pkt, size);
178 pkt->stream_index = 0;
182 /* note: we need to modify the packet size here to handle the last
188 AVInputFormat mp3_demuxer = {
190 NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
195 .flags= AVFMT_GENERIC_INDEX,
196 .extensions = "mp2,mp3,m2a", /* XXX: use probe */
200 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
201 static int id3v1_set_string(AVFormatContext *s, const char *key,
202 uint8_t *buf, int buf_size)
205 if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
206 strncpy(buf, tag->value, buf_size);
210 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
215 memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
219 count += id3v1_set_string(s, "TIT2", buf + 3, 30); //title
220 count += id3v1_set_string(s, "TPE1", buf + 33, 30); //author|artist
221 count += id3v1_set_string(s, "TALB", buf + 63, 30); //album
222 count += id3v1_set_string(s, "TDRL", buf + 93, 4); //date
223 count += id3v1_set_string(s, "comment", buf + 97, 30);
224 if ((tag = av_metadata_get(s->metadata, "TRCK", NULL, 0))) { //track
226 buf[126] = atoi(tag->value);
229 buf[127] = 0xFF; /* default to unknown genre */
230 if ((tag = av_metadata_get(s->metadata, "TCON", NULL, 0))) { //genre
231 for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
232 if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
244 static void id3v2_put_size(AVFormatContext *s, int size)
246 put_byte(s->pb, size >> 21 & 0x7f);
247 put_byte(s->pb, size >> 14 & 0x7f);
248 put_byte(s->pb, size >> 7 & 0x7f);
249 put_byte(s->pb, size & 0x7f);
252 static void id3v2_put_ttag(AVFormatContext *s, const char *buf, int len,
255 put_be32(s->pb, tag);
256 id3v2_put_size(s, len + 1);
258 put_byte(s->pb, 3); /* UTF-8 */
259 put_buffer(s->pb, buf, len);
263 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
265 put_buffer(s->pb, pkt->data, pkt->size);
266 put_flush_packet(s->pb);
270 static int mp3_write_trailer(struct AVFormatContext *s)
272 uint8_t buf[ID3v1_TAG_SIZE];
274 /* write the id3v1 tag */
275 if (id3v1_create_tag(s, buf) > 0) {
276 put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
277 put_flush_packet(s->pb);
281 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
284 AVOutputFormat mp2_muxer = {
286 NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
300 * Write an ID3v2.4 header at beginning of stream
303 static int mp3_write_header(struct AVFormatContext *s)
305 AVMetadataTag *t = NULL;
307 int64_t size_pos, cur_pos;
309 put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
311 put_byte(s->pb, 0); /* flags */
313 /* reserve space for size */
314 size_pos = url_ftell(s->pb);
317 ff_metadata_conv(&s->metadata, ff_id3v2_metadata_conv, NULL);
318 while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX))) {
321 if (t->key[0] == 'T' && strlen(t->key) == 4) {
323 for (i = 0; *ff_id3v2_tags[i]; i++)
324 if (AV_RB32(t->key) == AV_RB32(ff_id3v2_tags[i])) {
325 int len = strlen(t->value);
326 tag = AV_RB32(t->key);
327 totlen += len + ID3v2_HEADER_SIZE + 2;
328 id3v2_put_ttag(s, t->value, len + 1, tag);
333 if (!tag) { /* unknown tag, write as TXXX frame */
334 int len = strlen(t->key), len1 = strlen(t->value);
335 char *buf = av_malloc(len + len1 + 2);
337 return AVERROR(ENOMEM);
338 tag = MKBETAG('T', 'X', 'X', 'X');
340 strcpy(buf + len + 1, t->value);
341 id3v2_put_ttag(s, buf, len + len1 + 2, tag);
342 totlen += len + len1 + ID3v2_HEADER_SIZE + 3;
347 cur_pos = url_ftell(s->pb);
348 url_fseek(s->pb, size_pos, SEEK_SET);
349 id3v2_put_size(s, totlen);
350 url_fseek(s->pb, cur_pos, SEEK_SET);
355 AVOutputFormat mp3_muxer = {
357 NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),