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FFmpeg/libavformat/h261dec.c
Michael Niedermayer 8381ab1437 Merge remote-tracking branch 'qatar/master'
* qatar/master: (29 commits)
  ARM: disable ff_vector_fmul_vfp on VFPv3 systems
  ARM: check for VFPv3
  swscale: Remove unused variables in x86 code.
  doc: Drop DJGPP section, Libav now compiles out-of-the-box on FreeDOS.
  x86: Add appropriate ifdefs around certain AVX functions.
  cmdutils: use sws_freeContext() instead of av_freep().
  swscale: delay allocation of formatConvBuffer().
  swscale: fix build with --disable-swscale-alpha.
  movenc: Deprecate the global RTP hinting flag, use a private AVOption instead
  movenc: Add an AVClass for setting muxer specific options
  swscale: fix non-bitexact yuv2yuv[X2]() MMX/MMX2 functions.
  configure: report yasm/nasm presence properly
  tcp: make connect() timeout properly
  rawdec: factor video demuxer definitions into a macro.
  rtspdec: add initial_pause private option.
  lavf: deprecate AVFormatParameters.width/height.
  tty: add video_size private option.
  rawdec: add video_size private option.
  x11grab: add video_size private option.
  x11grab: factorize returning error codes.
  ...

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2011-05-27 23:48:22 +02:00

66 lines
1.9 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_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", CODEC_ID_H261)