Merge commit 'a7c1689d'

* commit 'a7c1689d':
  4xm: check that bits per sample is strictly positive
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/4xm.c

@@ -150,7 +150,7 @@ static int parse_strk(AVFormatContext *s,
 
     if (fourxm->tracks[track].channels    <= 0 ||
         fourxm->tracks[track].sample_rate <= 0 ||
-        fourxm->tracks[track].bits        < 0) {
+        fourxm->tracks[track].bits        <= 0) {
         av_log(s, AV_LOG_ERROR, "audio header invalid\n");
         return AVERROR_INVALIDDATA;
     }