diff --git a/internal/magic/magic.go b/internal/magic/magic.go
index 161187708..1cf09b466 100644
--- a/internal/magic/magic.go
+++ b/internal/magic/magic.go
@@ -227,6 +227,7 @@ var VideoExtensions = map[string]bool{
 	"m1v": true,
 	"m2v": true,
 	"m4v": true,
+	"mkv": true,
 }
 
 // HasExtension returns whether the file extension of filename is among