mpegtsenc: recognize .mts as MPEG Transport Stream

libavformat/mpegtsenc.c

@@ -1270,7 +1270,7 @@ AVOutputFormat ff_mpegts_muxer = {
     .name           = "mpegts",
     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-TS (MPEG-2 Transport Stream)"),
     .mime_type      = "video/x-mpegts",
-    .extensions     = "ts,m2t,m2ts",
+    .extensions     = "ts,m2t,m2ts,mts",
     .priv_data_size = sizeof(MpegTSWrite),
     .audio_codec    = AV_CODEC_ID_MP2,
     .video_codec    = AV_CODEC_ID_MPEG2VIDEO,