From 5abfae79ca6fbcbec559f4743e1d8c07a4d91518 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Reimar=20D=C3=B6ffinger?= <Reimar.Doeffinger@gmx.de>
Date: Thu, 17 Sep 2009 18:09:20 +0000
Subject: [PATCH] Improve SIFF probe by also checking the first tag is one of
 the expected.

Originally committed as revision 19898 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavformat/siff.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavformat/siff.c b/libavformat/siff.c
index 63fc0d6fac..1194f71bf6 100644
--- a/libavformat/siff.c
+++ b/libavformat/siff.c
@@ -60,11 +60,12 @@ typedef struct SIFFContext{
 
 static int siff_probe(AVProbeData *p)
 {
+    uint32_t tag = AV_RL32(p->buf + 8);
     /* check file header */
-    if (AV_RL32(p->buf) == TAG_SIFF)
-        return AVPROBE_SCORE_MAX;
-    else
+    if (AV_RL32(p->buf) != TAG_SIFF ||
+        (tag != TAG_VBV1 && tag != TAG_SOUN))
         return 0;
+    return AVPROBE_SCORE_MAX;
 }
 
 static int create_audio_stream(AVFormatContext *s, SIFFContext *c)