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 if(ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC)) {
46 buf0 += ff_id3v2_tag_len(buf0);
48 end = p->buf + p->buf_size - sizeof(uint32_t);
49 while(buf0 < end && !*buf0)
55 for(; buf < end; buf= buf2+1) {
58 for(frames = 0; buf2 < end; frames++) {
59 header = AV_RB32(buf2);
60 fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
65 max_frames = FFMAX(max_frames, frames);
69 // keep this in sync with ac3 probe, both need to avoid
70 // issues with MPEG-files!
71 if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
72 else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
73 else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
74 else if(buf0!=p->buf) return AVPROBE_SCORE_MAX/4-1;
75 else if(max_frames>=1) return 1;
77 //mpegps_mp3_unrecognized_format.mpg has max_frames=3
81 * Try to find Xing/Info/VBRI tags and compute duration from info therein
83 static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
86 int frames = -1; /* Total number of frames in file */
87 const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
92 if(ff_mpa_check_header(v) < 0)
95 if (ff_mpegaudio_decode_header(&c, v) == 0)
96 vbrtag_size = c.frame_size;
100 /* Check for Xing / Info tag */
101 url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
103 if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
106 frames = get_be32(s->pb);
109 /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
110 url_fseek(s->pb, base + 4 + 32, SEEK_SET);
112 if(v == MKBETAG('V', 'B', 'R', 'I')) {
113 /* Check tag version */
114 if(get_be16(s->pb) == 1) {
115 /* skip delay, quality and total bytes */
116 url_fseek(s->pb, 8, SEEK_CUR);
117 frames = 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 */
128 st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
133 static int mp3_read_header(AVFormatContext *s,
134 AVFormatParameters *ap)
139 st = av_new_stream(s, 0);
141 return AVERROR(ENOMEM);
143 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
144 st->codec->codec_id = CODEC_ID_MP3;
145 st->need_parsing = AVSTREAM_PARSE_FULL;
148 // lcm of all mp3 sample rates
149 av_set_pts_info(st, 64, 1, 14112000);
151 ff_id3v2_read(s, ID3v2_DEFAULT_MAGIC);
152 off = url_ftell(s->pb);
154 if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))
157 if (mp3_parse_vbr_tags(s, st, off) < 0)
158 url_fseek(s->pb, off, SEEK_SET);
160 /* the parameters will be extracted from the compressed bitstream */
164 #define MP3_PACKET_SIZE 1024
166 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
169 // AVStream *st = s->streams[0];
171 size= MP3_PACKET_SIZE;
173 ret= av_get_packet(s->pb, pkt, size);
175 pkt->stream_index = 0;
179 /* note: we need to modify the packet size here to handle the last
185 AVInputFormat mp3_demuxer = {
187 NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
192 .flags= AVFMT_GENERIC_INDEX,
193 .extensions = "mp2,mp3,m2a", /* XXX: use probe */
194 .metadata_conv = ff_id3v2_metadata_conv,
198 #if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
199 static int id3v1_set_string(AVFormatContext *s, const char *key,
200 uint8_t *buf, int buf_size)
203 if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
204 strncpy(buf, tag->value, buf_size);
208 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
213 memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
217 count += id3v1_set_string(s, "title", buf + 3, 30);
218 count += id3v1_set_string(s, "author", buf + 33, 30);
219 count += id3v1_set_string(s, "album", buf + 63, 30);
220 count += id3v1_set_string(s, "date", buf + 93, 4);
221 count += id3v1_set_string(s, "comment", buf + 97, 30);
222 if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
224 buf[126] = atoi(tag->value);
227 buf[127] = 0xFF; /* default to unknown genre */
228 if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
229 for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
230 if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
242 static void id3v2_put_size(AVFormatContext *s, int size)
244 put_byte(s->pb, size >> 21 & 0x7f);
245 put_byte(s->pb, size >> 14 & 0x7f);
246 put_byte(s->pb, size >> 7 & 0x7f);
247 put_byte(s->pb, size & 0x7f);
250 static void id3v2_put_ttag(AVFormatContext *s, const char *buf, int len,
253 put_be32(s->pb, tag);
254 id3v2_put_size(s, len + 1);
256 put_byte(s->pb, 3); /* UTF-8 */
257 put_buffer(s->pb, buf, len);
261 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
263 put_buffer(s->pb, pkt->data, pkt->size);
264 put_flush_packet(s->pb);
268 static int mp3_write_trailer(struct AVFormatContext *s)
270 uint8_t buf[ID3v1_TAG_SIZE];
272 /* write the id3v1 tag */
273 if (id3v1_create_tag(s, buf) > 0) {
274 put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
275 put_flush_packet(s->pb);
279 #endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
282 AVOutputFormat mp2_muxer = {
284 NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
298 * Write an ID3v2.4 header at beginning of stream
301 static int mp3_write_header(struct AVFormatContext *s)
303 AVMetadataTag *t = NULL;
305 int64_t size_pos, cur_pos;
307 put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
309 put_byte(s->pb, 0); /* flags */
311 /* reserve space for size */
312 size_pos = url_ftell(s->pb);
315 while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX))) {
318 if (t->key[0] == 'T' && strlen(t->key) == 4) {
320 for (i = 0; *ff_id3v2_tags[i]; i++)
321 if (AV_RB32(t->key) == AV_RB32(ff_id3v2_tags[i])) {
322 int len = strlen(t->value);
323 tag = AV_RB32(t->key);
324 totlen += len + ID3v2_HEADER_SIZE + 2;
325 id3v2_put_ttag(s, t->value, len + 1, tag);
330 if (!tag) { /* unknown tag, write as TXXX frame */
331 int len = strlen(t->key), len1 = strlen(t->value);
332 char *buf = av_malloc(len + len1 + 2);
334 return AVERROR(ENOMEM);
335 tag = MKBETAG('T', 'X', 'X', 'X');
337 strcpy(buf + len + 1, t->value);
338 id3v2_put_ttag(s, buf, len + len1 + 2, tag);
339 totlen += len + len1 + ID3v2_HEADER_SIZE + 3;
344 cur_pos = url_ftell(s->pb);
345 url_fseek(s->pb, size_pos, SEEK_SET);
346 id3v2_put_size(s, totlen);
347 url_fseek(s->pb, cur_pos, SEEK_SET);
352 AVOutputFormat mp3_muxer = {
354 NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
364 .metadata_conv = ff_id3v2_metadata_conv,