Rewrite h263_probe().

The new code should detect h263 even if the first startcode is damaged or
somewhere else than the first byte. It also passes probetest v2 as just
posted on ffmpeg-dev.

Originally committed as revision 19841 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2009-09-14 19:06:36 +00:00
parent 21ab5c5827
commit e4c01d408a
1 changed files with 25 additions and 6 deletions

View File

@ -455,14 +455,33 @@ static int h264_probe(AVProbeData *p)
#if CONFIG_H263_DEMUXER
static int h263_probe(AVProbeData *p)
{
int code;
const uint8_t *d;
uint64_t code= -1;
int i;
int valid_psc=0;
int invalid_psc=0;
int res_change=0;
int src_fmt, last_src_fmt=-1;
d = p->buf;
code = (d[0] << 14) | (d[1] << 6) | (d[2] >> 2);
if (code == 0x20) {
return 50;
for(i=0; i<p->buf_size; i++){
code = (code<<8) + p->buf[i];
if ((code & 0xfffffc0000) == 0x800000) {
src_fmt= (code>>2)&3;
if( src_fmt != last_src_fmt
&& last_src_fmt>0 && last_src_fmt<6
&& src_fmt<6)
res_change++;
if((code&0x300)==0x200 && src_fmt){
valid_psc++;
}else
invalid_psc++;
last_src_fmt= src_fmt;
}
}
if(valid_psc > 2*invalid_psc + 2*res_change + 2){
return 50;
}else if(valid_psc > 2*invalid_psc)
return 25;
return 0;
}
#endif