Merge commit 'c59967fa'

* commit 'c59967fa':
  h261: check the mtype index

Conflicts:
	libavcodec/h261dec.c

The right half of the check is impossible to be true and thus replaced by
an assert()

See: ec3cd74fMerged-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/h261dec.c

@@ -378,9 +378,11 @@ static int h261_decode_mb(H261Context *h)
     // Read mtype
     h->mtype = get_vlc2(&s->gb, h261_mtype_vlc.table, H261_MTYPE_VLC_BITS, 2);
     if (h->mtype < 0) {
-        av_log(s->avctx, AV_LOG_ERROR, "illegal mtype %d\n", h->mtype);
+        av_log(s->avctx, AV_LOG_ERROR, "Invalid mtype index %d\n",
+               h->mtype);
         return SLICE_ERROR;
     }
+    av_assert0(h->mtype < FF_ARRAY_ELEMS(ff_h261_mtype_map));
     h->mtype = ff_h261_mtype_map[h->mtype];
 
     // Read mquant