diff --git a/libavformat/isom_tags.c b/libavformat/isom_tags.c
index 2a29823b2e..4738171a9c 100644
--- a/libavformat/isom_tags.c
+++ b/libavformat/isom_tags.c
@@ -290,6 +290,7 @@ const AVCodecTag ff_codec_movaudio_tags[] = {
     { AV_CODEC_ID_AAC,             MKTAG('m', 'p', '4', 'a') },
     { AV_CODEC_ID_AC3,             MKTAG('a', 'c', '-', '3') }, /* ETSI TS 102 366 Annex F */
     { AV_CODEC_ID_AC3,             MKTAG('s', 'a', 'c', '3') }, /* Nero Recode */
+    { AV_CODEC_ID_AC4,             MKTAG('a', 'c', '-', '4') },
     { AV_CODEC_ID_ADPCM_IMA_QT,    MKTAG('i', 'm', 'a', '4') },
     { AV_CODEC_ID_ALAC,            MKTAG('a', 'l', 'a', 'c') },
     { AV_CODEC_ID_AMR_NB,          MKTAG('s', 'a', 'm', 'r') }, /* AMR-NB 3gp */