diff --git a/firefox/Dockerfile b/firefox/Dockerfile
index 591d67ba8..4e0711e51 100644
--- a/firefox/Dockerfile
+++ b/firefox/Dockerfile
@@ -10,6 +10,7 @@ RUN apt-get update && apt-get install -y \
 	&& apt-get update && apt-get install -y \
 	apulse \
 	ca-certificates \
+	ffmpeg \
 	firefox \
 	hicolor-icon-theme \
 	libasound2 \