diff --git a/amd64.dockerfile b/amd64.dockerfile
index eb6763c..9f22682 100644
--- a/amd64.dockerfile
+++ b/amd64.dockerfile
@@ -28,7 +28,7 @@ ENV youtubeSubtitleLanguage=en
 ENV enableAudioScript=true
 ENV enableVideoScript=true
 ENV matchDistance=5
-ENV videoformat="bestvideo+best+bestaudio --no-video-multistreams"
+ENV videoFormat="bestvideo+best+bestaudio --no-video-multistreams"
 
 RUN \
 	echo "*** install packages ***" && \