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/*
* 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/apetag.h" // for APE tag.
#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 + 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 = ff_mpa_decode_header(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;
av_channel_layout_uninit(&avctx->ch_layout);
av_channel_layout_default(&avctx->ch_layout, 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");
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size; /* parsers must not return error codes */
}
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;
}
if (flush && buf_size >= APE_TAG_FOOTER_BYTES && memcmp(buf, APE_TAG_PREAMBLE, 8) == 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return next;
}
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
const 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,
};
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