Try harder to avoid false positives for DV probe.

Require at least one signature match per provided 1MB of probe data,
and if there is only a single match, return at most MAX/4.
Fixes issue1382 but could/should probably still be improved.

Originally committed as revision 19848 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Reimar Döffinger 2009-09-14 22:03:07 +00:00
parent 98487a5b69
commit 6377de611a

View File

@ -488,6 +488,7 @@ static int dv_probe(AVProbeData *p)
{
unsigned state, marker_pos = 0;
int i;
int matches = 0;
if (p->buf_size < 5)
return 0;
@ -495,14 +496,19 @@ static int dv_probe(AVProbeData *p)
state = AV_RB32(p->buf);
for (i = 4; i < p->buf_size; i++) {
if ((state & 0xffffff7f) == 0x1f07003f)
return AVPROBE_SCORE_MAX*3/4; // not max to avoid dv in mov to match
matches++;
if (state == 0x003f0700 || state == 0xff3f0700)
marker_pos = i;
if (state == 0xff3f0701 && i - marker_pos == 80)
return AVPROBE_SCORE_MAX/4;
matches++;
state = (state << 8) | p->buf[i];
}
if (matches && p->buf_size / matches < 1024*1024) {
if (matches > 4)
return AVPROBE_SCORE_MAX*3/4; // not max to avoid dv in mov to match
return AVPROBE_SCORE_MAX/4;
}
return 0;
}