diff --git a/mp4-tree.js b/mp4-tree.js
index e99b888..083442b 100644
--- a/mp4-tree.js
+++ b/mp4-tree.js
@@ -62,6 +62,8 @@ class MP4Tree {
 					this.parse_avc1();
 				} else if (media_sample == 'mp4a') {
 					this.parse_mp4a();
+				} else if (media_sample == 'Opus') {
+					this.codecs.push('opus');
 				} else {
 					this.codecs.push('unsup codec');
 				}