isom: add 'mp1v' fourcc

As referenced in the CoreMedia API docs.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

libavformat/isom.c

@@ -169,6 +169,7 @@ const AVCodecTag ff_codec_movvideo_tags[] = {
     { AV_CODEC_ID_MPEG1VIDEO, MKTAG('m', '1', 'v', ' ') },
     { AV_CODEC_ID_MPEG1VIDEO, MKTAG('m', '1', 'v', '1') }, /* Apple MPEG-1 Camcorder */
     { AV_CODEC_ID_MPEG1VIDEO, MKTAG('m', 'p', 'e', 'g') }, /* MPEG */
+    { AV_CODEC_ID_MPEG1VIDEO, MKTAG('m', 'p', '1', 'v') }, /* CoreMedia CMVideoCodecType */
     { AV_CODEC_ID_MPEG2VIDEO, MKTAG('m', '2', 'v', '1') }, /* Apple MPEG-2 Camcorder */
     { AV_CODEC_ID_MPEG2VIDEO, MKTAG('h', 'd', 'v', '1') }, /* MPEG2 HDV 720p30 */
     { AV_CODEC_ID_MPEG2VIDEO, MKTAG('h', 'd', 'v', '2') }, /* MPEG2 HDV 1080i60 */