0,0 → 1,134 |
/* |
* MPEG Audio parser |
* Copyright (c) 2003 Fabrice Bellard |
* Copyright (c) 2003 Michael Niedermayer |
* |
* 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 "parser.h" |
#include "mpegaudiodecheader.h" |
#include "libavutil/common.h" |
#include "libavformat/id3v1.h" // for ID3v1_TAG_SIZE |
|
typedef struct MpegAudioParseContext { |
ParseContext pc; |
int frame_size; |
uint32_t header; |
int header_count; |
int no_bitrate; |
} MpegAudioParseContext; |
|
#define MPA_HEADER_SIZE 4 |
|
/* header + layer + bitrate + freq + lsf/mpeg25 */ |
#define SAME_HEADER_MASK \ |
(0xffe00000 | (3 << 17) | (3 << 10) | (3 << 19)) |
|
static int mpegaudio_parse(AVCodecParserContext *s1, |
AVCodecContext *avctx, |
const uint8_t **poutbuf, int *poutbuf_size, |
const uint8_t *buf, int buf_size) |
{ |
MpegAudioParseContext *s = s1->priv_data; |
ParseContext *pc = &s->pc; |
uint32_t state= pc->state; |
int i; |
int next= END_NOT_FOUND; |
int flush = !buf_size; |
|
for(i=0; i<buf_size; ){ |
if(s->frame_size){ |
int inc= FFMIN(buf_size - i, s->frame_size); |
i += inc; |
s->frame_size -= inc; |
state = 0; |
|
if(!s->frame_size){ |
next= i; |
break; |
} |
}else{ |
while(i<buf_size){ |
int ret, sr, channels, bit_rate, frame_size; |
enum AVCodecID codec_id = avctx->codec_id; |
|
state= (state<<8) + buf[i++]; |
|
ret = avpriv_mpa_decode_header2(state, &sr, &channels, &frame_size, &bit_rate, &codec_id); |
if (ret < 4) { |
if (i > 4) |
s->header_count = -2; |
} else { |
int header_threshold = avctx->codec_id != AV_CODEC_ID_NONE && avctx->codec_id != codec_id; |
if((state&SAME_HEADER_MASK) != (s->header&SAME_HEADER_MASK) && s->header) |
s->header_count= -3; |
s->header= state; |
s->header_count++; |
s->frame_size = ret-4; |
|
if (s->header_count > header_threshold) { |
avctx->sample_rate= sr; |
avctx->channels = channels; |
s1->duration = frame_size; |
avctx->codec_id = codec_id; |
if (s->no_bitrate || !avctx->bit_rate) { |
s->no_bitrate = 1; |
avctx->bit_rate += (bit_rate - avctx->bit_rate) / (s->header_count - header_threshold); |
} |
} |
|
if (s1->flags & PARSER_FLAG_COMPLETE_FRAMES) { |
s->frame_size = 0; |
next = buf_size; |
} else if (codec_id == AV_CODEC_ID_MP3ADU) { |
avpriv_report_missing_feature(avctx, |
"MP3ADU full parser"); |
return AVERROR_PATCHWELCOME; |
} |
|
break; |
} |
} |
} |
} |
|
pc->state= state; |
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
*poutbuf = NULL; |
*poutbuf_size = 0; |
return buf_size; |
} |
|
if (flush && buf_size >= ID3v1_TAG_SIZE && memcmp(buf, "TAG", 3) == 0) { |
*poutbuf = NULL; |
*poutbuf_size = 0; |
return next; |
} |
|
*poutbuf = buf; |
*poutbuf_size = buf_size; |
return next; |
} |
|
|
AVCodecParser ff_mpegaudio_parser = { |
.codec_ids = { AV_CODEC_ID_MP1, AV_CODEC_ID_MP2, AV_CODEC_ID_MP3, AV_CODEC_ID_MP3ADU }, |
.priv_data_size = sizeof(MpegAudioParseContext), |
.parser_parse = mpegaudio_parse, |
.parser_close = ff_parse_close, |
}; |