diff --git a/libavformat/isom.c b/libavformat/isom.c
index 13ceef0..bae4505 100644
--- a/libavformat/isom.c
+++ b/libavformat/isom.c
@@ -182,6 +182,7 @@ const AVCodecTag ff_codec_movvideo_tags[] = {
     { AV_CODEC_ID_H264, MKTAG('A', 'V', 'i', 'n') }, /* AVC-Intra with implicit SPS/PPS */
     { AV_CODEC_ID_H264, MKTAG('a', 'i', 'v', 'x') }, /* XAVC 10-bit 4:2:2 */
     { AV_CODEC_ID_H264, MKTAG('r', 'v', '6', '4') }, /* X-Com Radvision */
+    { AV_CODEC_ID_H264, MKTAG('x', 'a', 'l', 'g') }, /* XAVC-L HD422 produced by FCP */
 
     { AV_CODEC_ID_VP9,  MKTAG('v', 'p', '0', '9') }, /* VP9 */