diff --git a/libavformat/isom.c b/libavformat/isom.c
index a568c4d76c..36d5b6d0bf 100644
--- a/libavformat/isom.c
+++ b/libavformat/isom.c
@@ -132,7 +132,6 @@ const AVCodecTag codec_movvideo_tags[] = {
 
     { CODEC_ID_MPEG1VIDEO, MKTAG('m', '1', 'v', '1') }, /* Apple MPEG-1 Camcorder */
     { CODEC_ID_MPEG1VIDEO, MKTAG('m', 'p', 'e', 'g') }, /* MPEG */
-    { CODEC_ID_MPEG1VIDEO, MKTAG('m', '1', 'v', '1') },
     { CODEC_ID_MPEG2VIDEO, MKTAG('m', '2', 'v', '2') }, /* Apple MPEG-2 Camcorder */
     { CODEC_ID_MPEG2VIDEO, MKTAG('h', 'd', 'v', '1') }, /* MPEG2 HDV 720p30 */
     { CODEC_ID_MPEG2VIDEO, MKTAG('h', 'd', 'v', '2') }, /* MPEG2 HDV 1080i60 */
@@ -170,7 +169,6 @@ const AVCodecTag codec_movvideo_tags[] = {
     { CODEC_ID_MPEG2VIDEO, MKTAG('x', 'd', 'v', 'e') }, /* XDCAM EX 1080p25 VBR */
     { CODEC_ID_MPEG2VIDEO, MKTAG('x', 'd', 'v', 'f') }, /* XDCAM EX 1080p30 VBR */
     { CODEC_ID_MPEG2VIDEO, MKTAG('A', 'V', 'm', 'p') }, /* AVID IMX PAL */
-    { CODEC_ID_MPEG2VIDEO, MKTAG('m', '2', 'v', '1') },
 
     { CODEC_ID_JPEG2000, MKTAG('m', 'j', 'p', '2') }, /* JPEG 2000 produced by FCP */