mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-26 19:01:44 +02:00
66 lines
2.0 KiB
C
66 lines
2.0 KiB
C
/*
|
|
* RAW H.261 video demuxer
|
|
* Copyright (c) 2009 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 "libavcodec/get_bits.h"
|
|
#include "avformat.h"
|
|
#include "rawdec.h"
|
|
|
|
static int h261_probe(AVProbeData *p)
|
|
{
|
|
uint32_t code= -1;
|
|
int i;
|
|
int valid_psc=0;
|
|
int invalid_psc=0;
|
|
int next_gn=0;
|
|
int src_fmt=0;
|
|
GetBitContext gb;
|
|
|
|
init_get_bits8(&gb, p->buf, p->buf_size);
|
|
|
|
for(i=0; i<p->buf_size*8; i++){
|
|
if ((code & 0x01ff0000) || !(code & 0xff00)) {
|
|
code = (code<<8) + get_bits(&gb, 8);
|
|
i += 7;
|
|
} else
|
|
code = (code<<1) + get_bits1(&gb);
|
|
if ((code & 0xffff0000) == 0x10000) {
|
|
int gn= (code>>12)&0xf;
|
|
if(!gn)
|
|
src_fmt= code&8;
|
|
if(gn != next_gn) invalid_psc++;
|
|
else valid_psc++;
|
|
|
|
if(src_fmt){ // CIF
|
|
next_gn= (gn+1 )%13;
|
|
}else{ //QCIF
|
|
next_gn= (gn+1+!!gn)% 7;
|
|
}
|
|
}
|
|
}
|
|
if(valid_psc > 2*invalid_psc + 6){
|
|
return AVPROBE_SCORE_EXTENSION;
|
|
}else if(valid_psc > 2*invalid_psc + 2)
|
|
return AVPROBE_SCORE_EXTENSION / 2;
|
|
return 0;
|
|
}
|
|
|
|
FF_DEF_RAWVIDEO_DEMUXER(h261, "raw H.261", h261_probe, "h261", AV_CODEC_ID_H261)
|