diff --git a/Dockerfile b/Dockerfile
index 3e31b1f..f6992a8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -21,6 +21,7 @@ RUN \
 		opus-tools \
 		jq \
 		git \
+		mkvtoolnix \
 		ffmpeg && \
 	echo "************ setup SMA ************" && \
 	echo "************ setup directory ************" && \