diff --git a/Doc/Makefile b/Doc/Makefile
index cfe73962eee40dc1de58a0ad71684f0dfcc4d492..cc409787bda027befbd5a020f31142e6934a18d1 100644
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -43,7 +43,7 @@ JAVADOCDESTDIR=${BUILDNAVI}/Ref/api
 #Video webm-->mp4 conversion rule
 #
 %.webm.mp4:%.webm
-	avconv -i $< -acodec libx264 -b:v 256k -c:a libvorbis $<.mp4 || rm -f $<.mp4
+	avconv -i $< -acodec libx264  -c:a libvorbis -r 10 $<.mp4 || rm -f $<.mp4
 
 webmSet = $(shell /bin/ls target/*/Ref/Video/*.webm)
 mp4Set  = $(foreach webmFile, $(webmSet), $(webmFile).mp4 )