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ffmpeg/libavformat/mp3.c
Anton Khirnov 7fd5aeb3e5 Only read ID3v1 tag if ID3v2 isn't present or is empty. 
This prevents the demuxer from exporting multiple semantically identical but
differently named tags.

Patch by Anton Khirnov, wyskas gmail

Originally committed as revision 20175 to svn://svn.ffmpeg.org/ffmpeg/trunk
2009-10-05 21:36:56 +00:00

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/*
* MP3 muxer and demuxer
* Copyright (c) 2003 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <strings.h>
#include "libavutil/avstring.h"
#include "avformat.h"
#include "id3v2.h"
#include "id3v1.h"
#if CONFIG_MP3_DEMUXER
#include "libavcodec/mpegaudio.h"
#include "libavcodec/mpegaudiodecheader.h"
/* mp3 read */
static int mp3_read_probe(AVProbeData *p)
{
int max_frames, first_frames = 0;
int fsize, frames, sample_rate;
uint32_t header;
uint8_t *buf, *buf0, *buf2, *end;
AVCodecContext avctx;
buf0 = p->buf;
if(ff_id3v2_match(buf0)) {
buf0 += ff_id3v2_tag_len(buf0);
}
max_frames = 0;
buf = buf0;
end = p->buf + p->buf_size - sizeof(uint32_t);
for(; buf < end; buf= buf2+1) {
buf2 = buf;
for(frames = 0; buf2 < end; frames++) {
header = AV_RB32(buf2);
fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
if(fsize < 0)
break;
buf2 += fsize;
}
max_frames = FFMAX(max_frames, frames);
if(buf == buf0)
first_frames= frames;
}
// keep this in sync with ac3 probe, both need to avoid
// issues with MPEG-files!
if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
else if(buf0!=p->buf) return AVPROBE_SCORE_MAX/4-1;
else if(max_frames>=1) return 1;
else return 0;
//mpegps_mp3_unrecognized_format.mpg has max_frames=3
}
/**
* Try to find Xing/Info/VBRI tags and compute duration from info therein
*/
static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
{
uint32_t v, spf;
int frames = -1; /* Total number of frames in file */
const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
MPADecodeHeader c;
int vbrtag_size = 0;
v = get_be32(s->pb);
if(ff_mpa_check_header(v) < 0)
return -1;
if (ff_mpegaudio_decode_header(&c, v) == 0)
vbrtag_size = c.frame_size;
if(c.layer != 3)
return -1;
/* Check for Xing / Info tag */
url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
v = get_be32(s->pb);
if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
v = get_be32(s->pb);
if(v & 0x1)
frames = get_be32(s->pb);
}
/* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
url_fseek(s->pb, base + 4 + 32, SEEK_SET);
v = get_be32(s->pb);
if(v == MKBETAG('V', 'B', 'R', 'I')) {
/* Check tag version */
if(get_be16(s->pb) == 1) {
/* skip delay, quality and total bytes */
url_fseek(s->pb, 8, SEEK_CUR);
frames = get_be32(s->pb);
}
}
if(frames < 0)
return -1;
/* Skip the vbr tag frame */
url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
st->time_base);
return 0;
}
static int mp3_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
AVStream *st;
int64_t off;
st = av_new_stream(s, 0);
if (!st)
return AVERROR(ENOMEM);
st->codec->codec_type = CODEC_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_MP3;
st->need_parsing = AVSTREAM_PARSE_FULL;
st->start_time = 0;
ff_id3v2_read(s);
if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))
ff_id3v1_read(s);
off = url_ftell(s->pb);
if (mp3_parse_vbr_tags(s, st, off) < 0)
url_fseek(s->pb, off, SEEK_SET);
/* the parameters will be extracted from the compressed bitstream */
return 0;
}
#define MP3_PACKET_SIZE 1024
static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret, size;
// AVStream *st = s->streams[0];
size= MP3_PACKET_SIZE;
ret= av_get_packet(s->pb, pkt, size);
pkt->stream_index = 0;
if (ret <= 0) {
return AVERROR(EIO);
}
/* note: we need to modify the packet size here to handle the last
packet */
pkt->size = ret;
return ret;
}
AVInputFormat mp3_demuxer = {
"mp3",
NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
0,
mp3_read_probe,
mp3_read_header,
mp3_read_packet,
.flags= AVFMT_GENERIC_INDEX,
.extensions = "mp2,mp3,m2a", /* XXX: use probe */
.metadata_conv = ff_id3v2_metadata_conv,
};
#endif
#if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
static int id3v1_set_string(AVFormatContext *s, const char *key,
uint8_t *buf, int buf_size)
{
AVMetadataTag *tag;
if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
strncpy(buf, tag->value, buf_size);
return !!tag;
}
static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
{
AVMetadataTag *tag;
int i, count = 0;
memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
buf[0] = 'T';
buf[1] = 'A';
buf[2] = 'G';
count += id3v1_set_string(s, "title", buf + 3, 30);
count += id3v1_set_string(s, "author", buf + 33, 30);
count += id3v1_set_string(s, "album", buf + 63, 30);
count += id3v1_set_string(s, "year", buf + 93, 4);
count += id3v1_set_string(s, "comment", buf + 97, 30);
if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
buf[125] = 0;
buf[126] = atoi(tag->value);
count++;
}
buf[127] = 0xFF; /* default to unknown genre */
if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
buf[127] = i;
count++;
break;
}
}
}
return count;
}
/* simple formats */
static void id3v2_put_size(AVFormatContext *s, int size)
{
put_byte(s->pb, size >> 21 & 0x7f);
put_byte(s->pb, size >> 14 & 0x7f);
put_byte(s->pb, size >> 7 & 0x7f);
put_byte(s->pb, size & 0x7f);
}
static void id3v2_put_ttag(AVFormatContext *s, const char *buf, int len,
uint32_t tag)
{
put_be32(s->pb, tag);
id3v2_put_size(s, len + 1);
put_be16(s->pb, 0);
put_byte(s->pb, 3); /* UTF-8 */
put_buffer(s->pb, buf, len);
}
/**
* Write an ID3v2.4 header at beginning of stream
*/
static int mp3_write_header(struct AVFormatContext *s)
{
AVMetadataTag *t = NULL;
int totlen = 0;
int64_t size_pos, cur_pos;
put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
put_byte(s->pb, 0);
put_byte(s->pb, 0); /* flags */
/* reserve space for size */
size_pos = url_ftell(s->pb);
put_be32(s->pb, 0);
while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX))) {
uint32_t tag = 0;
if (t->key[0] == 'T' && strcmp(t->key, "TSSE")) {
int i;
for (i = 0; *ff_id3v2_tags[i]; i++)
if (AV_RB32(t->key) == AV_RB32(ff_id3v2_tags[i])) {
int len = strlen(t->value);
tag = AV_RB32(t->key);
totlen += len + ID3v2_HEADER_SIZE + 2;
id3v2_put_ttag(s, t->value, len + 1, tag);
break;
}
}
if (!tag) { /* unknown tag, write as TXXX frame */
int len = strlen(t->key), len1 = strlen(t->value);
char *buf = av_malloc(len + len1 + 2);
if (!buf)
return AVERROR(ENOMEM);
tag = MKBETAG('T', 'X', 'X', 'X');
strcpy(buf, t->key);
strcpy(buf + len + 1, t->value);
id3v2_put_ttag(s, buf, len + len1 + 2, tag);
totlen += len + len1 + ID3v2_HEADER_SIZE + 3;
av_free(buf);
}
}
if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
totlen += strlen(LIBAVFORMAT_IDENT) + ID3v2_HEADER_SIZE + 2;
id3v2_put_ttag(s, LIBAVFORMAT_IDENT, strlen(LIBAVFORMAT_IDENT) + 1,
MKBETAG('T', 'S', 'S', 'E'));
}
cur_pos = url_ftell(s->pb);
url_fseek(s->pb, size_pos, SEEK_SET);
id3v2_put_size(s, totlen);
url_fseek(s->pb, cur_pos, SEEK_SET);
return 0;
}
static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
{
put_buffer(s->pb, pkt->data, pkt->size);
put_flush_packet(s->pb);
return 0;
}
static int mp3_write_trailer(struct AVFormatContext *s)
{
uint8_t buf[ID3v1_TAG_SIZE];
/* write the id3v1 tag */
if (id3v1_create_tag(s, buf) > 0) {
put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
put_flush_packet(s->pb);
}
return 0;
}
#endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
#if CONFIG_MP2_MUXER
AVOutputFormat mp2_muxer = {
"mp2",
NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
"audio/x-mpeg",
"mp2,m2a",
0,
CODEC_ID_MP2,
CODEC_ID_NONE,
NULL,
mp3_write_packet,
mp3_write_trailer,
};
#endif
#if CONFIG_MP3_MUXER
AVOutputFormat mp3_muxer = {
"mp3",
NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
"audio/x-mpeg",
"mp3",
0,
CODEC_ID_MP3,
CODEC_ID_NONE,
mp3_write_header,
mp3_write_packet,
mp3_write_trailer,
.metadata_conv = ff_id3v2_metadata_conv,
};
#endif
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