mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
65 lines
1.9 KiB
65 lines
1.9 KiB
/* |
|
* RAW H.261 video demuxer |
|
* Copyright (c) 2009 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 "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_bits(&gb, p->buf, p->buf_size*8); |
|
|
|
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 50; |
|
}else if(valid_psc > 2*invalid_psc + 2) |
|
return 25; |
|
return 0; |
|
} |
|
|
|
FF_DEF_RAWVIDEO_DEMUXER(h261, "raw H.261", h261_probe, "h261", AV_CODEC_ID_H261)
|
|
|