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/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "mpegaudio.h"
static int mp3_header_compress(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size, int keyframe){
uint32_t header, extraheader;
int mode_extension, header_size;
if(avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL){
av_log(avctx, AV_LOG_ERROR, "not standards compliant\n");
return -1;
}
header = AV_RB32(buf);
mode_extension= (header>>4)&3;
if(ff_mpa_check_header(header) < 0 || (header&0x60000) != 0x20000){
output_unchanged:
*poutbuf= (uint8_t *) buf;
*poutbuf_size= buf_size;
av_log(avctx, AV_LOG_INFO, "cannot compress %08X\n", header);
return 0;
}
if(avctx->extradata_size == 0){
avctx->extradata_size=15;
avctx->extradata= av_malloc(avctx->extradata_size);
strcpy(avctx->extradata, "FFCMP3 0.0");
memcpy(avctx->extradata+11, buf, 4);
}
if(avctx->extradata_size != 15){
av_log(avctx, AV_LOG_ERROR, "Extradata invalid\n");
return -1;
}
extraheader = AV_RB32(avctx->extradata+11);
if((extraheader&MP3_MASK) != (header&MP3_MASK))
goto output_unchanged;
header_size= (header&0x10000) ? 4 : 6;
*poutbuf_size= buf_size - header_size;
*poutbuf= av_malloc(buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE);
memcpy(*poutbuf, buf + header_size, buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE);
if(avctx->channels==2){
if((header & (3<<19)) != 3<<19){
(*poutbuf)[1] &= 0x3F;
(*poutbuf)[1] |= mode_extension<<6;
FFSWAP(int, (*poutbuf)[1], (*poutbuf)[2]);
}else{
(*poutbuf)[1] &= 0x8F;
(*poutbuf)[1] |= mode_extension<<4;
}
}
return 1;
}
AVBitStreamFilter ff_mp3_header_compress_bsf={
"mp3comp",
0,
mp3_header_compress,
};
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