From 55851640fa9e4d23c6c32bf33a46927815544040 Mon Sep 17 00:00:00 2001
From: Carl Eugen Hoyos <ceffmpeg@gmail.com>
Date: Thu, 18 Apr 2019 00:50:48 +0200
Subject: [PATCH] lavf/vc1dec: Reduce probe score for streams with invalid
frames.
Fixes ticket 7853.
---
libavformat/vc1dec.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
@@ -26,7 +26,7 @@
static int vc1_probe(const AVProbeData *p)
{
- int seq = 0, entry = 0, frame = 0, i;
+ int seq = 0, entry = 0, invalid = 0, frame = 0, i;
for (i = 0; i < p->buf_size + 5; i++) {
uint32_t code = AV_RB32(p->buf + i);
@@ -39,16 +39,19 @@ static int vc1_probe(const AVProbeData *p)
profile = (p->buf[i] & 0xc0) >> 6;
if (profile != PROFILE_ADVANCED) {
seq = 0;
+ invalid++;
continue;
}
level = (p->buf[i] & 0x38) >> 3;
if (level >= 5) {
seq = 0;
+ invalid++;
continue;
}
chromaformat = (p->buf[i] & 0x6) >> 1;
if (chromaformat != 1) {
seq = 0;
+ invalid++;
continue;
}
seq++;
@@ -56,8 +59,10 @@ static int vc1_probe(const AVProbeData *p)
break;
}
case VC1_CODE_ENTRYPOINT:
- if (!seq)
+ if (!seq) {
+ invalid++;
continue;
+ }
entry++;
i += 2;
break;
@@ -71,7 +76,7 @@ static int vc1_probe(const AVProbeData *p)
}
}
- if (frame > 1)
+ if (frame > 1 && frame >> 1 > invalid)
return AVPROBE_SCORE_EXTENSION / 2 + 1;
if (frame == 1)
return AVPROBE_SCORE_EXTENSION / 4;
--
1.7.10.4