0,0 → 1,97 |
/* |
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> |
* |
* 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/common.h" |
#include "libavutil/intreadwrite.h" |
#include "avcodec.h" |
#include "mpegaudiodecheader.h" |
#include "mpegaudiodata.h" |
|
|
static int mp3_header_decompress(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; |
int sample_rate= avctx->sample_rate; |
int sample_rate_index=0; |
int lsf, mpeg25, bitrate_index, frame_size; |
|
header = AV_RB32(buf); |
if(ff_mpa_check_header(header) >= 0){ |
*poutbuf= (uint8_t *) buf; |
*poutbuf_size= buf_size; |
|
return 0; |
} |
|
if(avctx->extradata_size != 15 || strcmp(avctx->extradata, "FFCMP3 0.0")){ |
av_log(avctx, AV_LOG_ERROR, "Extradata invalid %d\n", avctx->extradata_size); |
return -1; |
} |
|
header= AV_RB32(avctx->extradata+11) & MP3_MASK; |
|
lsf = sample_rate < (24000+32000)/2; |
mpeg25 = sample_rate < (12000+16000)/2; |
sample_rate_index= (header>>10)&3; |
sample_rate= avpriv_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25); //in case sample rate is a little off |
|
for(bitrate_index=2; bitrate_index<30; bitrate_index++){ |
frame_size = avpriv_mpa_bitrate_tab[lsf][2][bitrate_index>>1]; |
frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1); |
if(frame_size == buf_size + 4) |
break; |
if(frame_size == buf_size + 6) |
break; |
} |
if(bitrate_index == 30){ |
av_log(avctx, AV_LOG_ERROR, "Could not find bitrate_index.\n"); |
return -1; |
} |
|
header |= (bitrate_index&1)<<9; |
header |= (bitrate_index>>1)<<12; |
header |= (frame_size == buf_size + 4)<<16; //FIXME actually set a correct crc instead of 0 |
|
*poutbuf_size= frame_size; |
*poutbuf= av_malloc(frame_size + FF_INPUT_BUFFER_PADDING_SIZE); |
memcpy(*poutbuf + frame_size - buf_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE); |
|
if(avctx->channels==2){ |
uint8_t *p= *poutbuf + frame_size - buf_size; |
if(lsf){ |
FFSWAP(int, p[1], p[2]); |
header |= (p[1] & 0xC0)>>2; |
p[1] &= 0x3F; |
}else{ |
header |= p[1] & 0x30; |
p[1] &= 0xCF; |
} |
} |
|
AV_WB32(*poutbuf, header); |
|
return 1; |
} |
|
AVBitStreamFilter ff_mp3_header_decompress_bsf={ |
.name = "mp3decomp", |
.filter = mp3_header_decompress, |
}; |