isom: add support for DNxHR codec family

This is actually similar to DNxHD.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/isom.c

@@ -240,6 +240,7 @@ const AVCodecTag ff_codec_movvideo_tags[] = {
 
     { AV_CODEC_ID_DIRAC,     MKTAG('d', 'r', 'a', 'c') },
     { AV_CODEC_ID_DNXHD,     MKTAG('A', 'V', 'd', 'n') }, /* AVID DNxHD */
+    { AV_CODEC_ID_DNXHD,     MKTAG('A', 'V', 'd', 'h') }, /* AVID DNxHR */
     { AV_CODEC_ID_H263,      MKTAG('H', '2', '6', '3') },
     { AV_CODEC_ID_MSMPEG4V3, MKTAG('3', 'I', 'V', 'D') }, /* 3ivx DivX Doctor */
     { AV_CODEC_ID_RAWVIDEO,  MKTAG('A', 'V', '1', 'x') }, /* AVID 1:1x */