diff --git a/libavformat/raw.c b/libavformat/raw.c
index e3d460fafb..e03fad5e1e 100644
--- a/libavformat/raw.c
+++ b/libavformat/raw.c
@@ -429,7 +429,7 @@ static int ac3_probe(AVProbeData *p)
             first_frames = frames;
     }
     if   (first_frames>=3) return AVPROBE_SCORE_MAX * 3 / 4;
-    else if(max_frames>=2 || first_frames>=1) return AVPROBE_SCORE_MAX / 2;
+    else if(max_frames>=3) return AVPROBE_SCORE_MAX / 2;
     else if(max_frames>=1) return 1;
     else                   return 0;
 }