rtpdec: check av_new_packet() return value

Fixes CID733715
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/rtpdec.c

@@ -560,7 +560,8 @@ static int rtp_parse_packet_internal(RTPDemuxContext *s, AVPacket *pkt,
             h = AV_RB32(buf);
             len -= 4;
             buf += 4;
-            av_new_packet(pkt, len);
+            if (av_new_packet(pkt, len) < 0)
+                return AVERROR(ENOMEM);
             memcpy(pkt->data, buf, len);
             break;
         case AV_CODEC_ID_MPEG1VIDEO:
@@ -578,11 +579,13 @@ static int rtp_parse_packet_internal(RTPDemuxContext *s, AVPacket *pkt,
                 buf += 4;
                 len -= 4;
             }
-            av_new_packet(pkt, len);
+            if (av_new_packet(pkt, len) < 0)
+                return AVERROR(ENOMEM);
             memcpy(pkt->data, buf, len);
             break;
         default:
-            av_new_packet(pkt, len);
+            if (av_new_packet(pkt, len) < 0)
+                return AVERROR(ENOMEM);
             memcpy(pkt->data, buf, len);
             break;
         }