ffmpeg/libavformat/mp3dec.c
Michael Niedermayer 976a8b2179 Merge remote-tracking branch 'qatar/master'
* qatar/master: (40 commits)
  H.264: template left MB handling
  H.264: faster fill_decode_caches
  H.264: faster write_back_*
  H.264: faster fill_filter_caches
  H.264: make filter_mb_fast support the case of unavailable top mb
  Do not include log.h in avutil.h
  Do not include pixfmt.h in avutil.h
  Do not include rational.h in avutil.h
  Do not include mathematics.h in avutil.h
  Do not include intfloat_readwrite.h in avutil.h
  Remove return statements following infinite loops without break
  RTSP: Doxygen comment cleanup
  doxygen: Escape '\' in Doxygen documentation.
  md5: cosmetics
  md5: use AV_WL32 to write result
  md5: add fate test
  md5: include correct headers
  md5: fix test program
  doxygen: Drop array size declarations from Doxygen parameter names.
  doxygen: Fix parameter names to match the function prototypes.
  ...

Conflicts:
	libavcodec/x86/dsputil_mmx.c
	libavformat/flvenc.c
	libavformat/oggenc.c
	libavformat/wtv.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2011-07-04 00:45:21 +02:00

200 lines
5.6 KiB
C

/*
* MP3 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 "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/dict.h"
#include "libavutil/mathematics.h"
#include "avformat.h"
#include "id3v2.h"
#include "id3v1.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;
end = p->buf + p->buf_size - sizeof(uint32_t);
while(buf0 < end && !*buf0)
buf0++;
max_frames = 0;
buf = buf0;
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(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;
unsigned frames = 0; /* Total number of frames in file */
unsigned size = 0; /* Total number of bytes in the stream */
const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
MPADecodeHeader c;
int vbrtag_size = 0;
v = avio_rb32(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 */
avio_skip(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1]);
v = avio_rb32(s->pb);
if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
v = avio_rb32(s->pb);
if(v & 0x1)
frames = avio_rb32(s->pb);
if(v & 0x2)
size = avio_rb32(s->pb);
}
/* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
avio_seek(s->pb, base + 4 + 32, SEEK_SET);
v = avio_rb32(s->pb);
if(v == MKBETAG('V', 'B', 'R', 'I')) {
/* Check tag version */
if(avio_rb16(s->pb) == 1) {
/* skip delay and quality */
avio_skip(s->pb, 4);
frames = avio_rb32(s->pb);
size = avio_rb32(s->pb);
}
}
if(!frames && !size)
return -1;
/* Skip the vbr tag frame */
avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
if(frames)
st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
st->time_base);
if(size && frames)
st->codec->bit_rate = av_rescale(size, 8 * c.sample_rate, frames * (int64_t)spf);
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 = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_MP3;
st->need_parsing = AVSTREAM_PARSE_FULL;
st->start_time = 0;
// lcm of all mp3 sample rates
av_set_pts_info(st, 64, 1, 14112000);
off = avio_tell(s->pb);
if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
ff_id3v1_read(s);
if (mp3_parse_vbr_tags(s, st, off) < 0)
avio_seek(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);
}
if (ret > ID3v1_TAG_SIZE &&
memcmp(&pkt->data[ret - ID3v1_TAG_SIZE], "TAG", 3) == 0)
ret -= ID3v1_TAG_SIZE;
/* note: we need to modify the packet size here to handle the last
packet */
pkt->size = ret;
return ret;
}
AVInputFormat ff_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 */
};