avformat/flvenc: Check pts for mpeg4/h264 (which need the value)

Fixes: Ticket8152

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/flvenc.c

@@ -928,6 +928,12 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
                "Packets are not in the proper order with respect to DTS\n");
         return AVERROR(EINVAL);
     }
+    if (par->codec_id == AV_CODEC_ID_H264 || par->codec_id == AV_CODEC_ID_MPEG4) {
+        if (pkt->pts == AV_NOPTS_VALUE) {
+            av_log(s, AV_LOG_ERROR, "Packet is missing PTS\n");
+            return AVERROR(EINVAL);
+        }
+    }
 
     ts = pkt->dts;