diff --git a/amd64.dockerfile b/amd64.dockerfile
index b22ed89..322023e 100644
--- a/amd64.dockerfile
+++ b/amd64.dockerfile
@@ -27,6 +27,7 @@ ENV SMA_PATH /usr/local/sma
 ENV youtubeSubtitleLanguage=en
 ENV enableAudioScript=true
 ENV enableVideoScript=true
+ENV matchDistance=5
 
 RUN \
 	echo "*** install packages ***" && \