diff --git a/go_backend/library_scan_formats.go b/go_backend/library_scan_formats.go
index 26d46dc4..23dade0b 100644
--- a/go_backend/library_scan_formats.go
+++ b/go_backend/library_scan_formats.go
@@ -258,6 +258,8 @@ func libraryFormatForM4ACodec(codec string) string {
 		return "ac3"
 	case "ac4", "ac-4":
 		return "ac4"
+	case "opus":
+		return "opus"
 	case "aac", "mp4a":
 		return "m4a"
 	default:
diff --git a/go_backend/metadata_m4a.go b/go_backend/metadata_m4a.go
index 39492c69..bbd788f8 100644
--- a/go_backend/metadata_m4a.go
+++ b/go_backend/metadata_m4a.go
@@ -842,6 +842,8 @@ func normalizeM4AAudioCodec(atomType string) string {
 		return "ac3"
 	case "ac-4":
 		return "ac4"
+	case "Opus":
+		return "opus"
 	default:
 		return strings.TrimSpace(atomType)
 	}
diff --git a/go_backend/metadata_m4a_quality_test.go b/go_backend/metadata_m4a_quality_test.go
index 1d9a64f6..e17862a7 100644
--- a/go_backend/metadata_m4a_quality_test.go
+++ b/go_backend/metadata_m4a_quality_test.go
@@ -56,6 +56,7 @@ func TestM4ACodecFormatMapping(t *testing.T) {
 		"ec-3": "eac3",
 		"ac-3": "ac3",
 		"ac-4": "ac4",
+		"Opus": "opus",
 	}
 	for atomType, want := range cases {
 		if got := normalizeM4AAudioCodec(atomType); got != want {
@@ -69,6 +70,9 @@ func TestM4ACodecFormatMapping(t *testing.T) {
 	if got := libraryFormatForM4ACodec("eac3"); got != "eac3" {
 		t.Fatalf("libraryFormatForM4ACodec(eac3) = %q", got)
 	}
+	if got := libraryFormatForM4ACodec("Opus"); got != "opus" {
+		t.Fatalf("libraryFormatForM4ACodec(Opus) = %q", got)
+	}
 	if got := libraryFormatForM4ACodec("aac"); got != "m4a" {
 		t.Fatalf("libraryFormatForM4ACodec(aac) = %q", got)
 	}