Merge commit '2ffb0598'

* commit '2ffb0598':
  mlpdec: check for negative index

Conflicts:
	libavcodec/mlpdec.c

See: 8491ac3aMerged-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mlpdec.c

@@ -583,7 +583,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
             ch_assign = av_get_channel_layout_channel_index(s->ch_layout,
                                                             channel);
         }
-        if ((unsigned)ch_assign > s->max_matrix_channel) {
+        if (ch_assign < 0 || ch_assign > s->max_matrix_channel) {
             avpriv_request_sample(m->avctx,
                                   "Assignment of matrix channel %d to invalid output channel %d",
                                   ch, ch_assign);