libavformat/rawenc: add dnxhr raw format extension

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

libavformat/rawenc.c

@@ -128,7 +128,7 @@ AVOutputFormat ff_dirac_muxer = {
 AVOutputFormat ff_dnxhd_muxer = {
     .name              = "dnxhd",
     .long_name         = NULL_IF_CONFIG_SMALL("raw DNxHD (SMPTE VC-3)"),
-    .extensions        = "dnxhd",
+    .extensions        = "dnxhd,dnxhr",
     .audio_codec       = AV_CODEC_ID_NONE,
     .video_codec       = AV_CODEC_ID_DNXHD,
     .write_header      = force_one_stream,