mpegvideo_probe: dont be too picky on spec compliance and the lack of system startcodes.

Fixes Ticket620
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/mpegvideodec.c

@@ -50,8 +50,8 @@ static int mpegvideo_probe(AVProbeData *p)
             else if((code & 0x1e0) == AUDIO_ID)   apes++;
         }
     }
-    if(seq && seq*9<=pic*10 && pic*9<=slice*10 && !pspack && !apes && !vpes)
-        return pic>1 ? AVPROBE_SCORE_MAX/2+1 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
+    if(seq && seq*9<=pic*10 && pic*9<=slice*10 && !pspack && !apes)
+        return (pic>1 && !vpes) ? AVPROBE_SCORE_MAX/2+1 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
     return 0;
 }