avformat/mpeg: increase score for short mpeg-ps by 1

Fixes Ticket 3855

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

libavformat/mpeg.c

@@ -101,7 +101,7 @@ static int mpegps_probe(AVProbeData *p)
 
     if (sys > invalid && sys * 9 <= pspack * 10)
         return (audio > 12 || vid > 3 || pspack > 2) ? AVPROBE_SCORE_EXTENSION + 2
-                                                     : AVPROBE_SCORE_EXTENSION / 2; // 1 more than .mpg
+                                                     : AVPROBE_SCORE_EXTENSION / 2 + 1; // 1 more than .mpg
     if (pspack > invalid && (priv1 + vid + audio) * 10 >= pspack * 9)
         return pspack > 2 ? AVPROBE_SCORE_EXTENSION + 2
                           : AVPROBE_SCORE_EXTENSION / 2; // 1 more than .mpg