How to insert small time counter in video?

I would like to insert some small rectangle with time counter in some corner in my video. How to do that most simple?

It could be possible to do SVG image for every number. But quite hard to work with so many SVG images.

Also there is something like mlt XML format http://www.mltframework.org/bin/view/MLT/MltXml
<mlt>
<playlist>
<producer in="0" mlt_service="pango" out="15" text="00:01" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:02" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:03" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:04" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:05" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:06" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:07" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:08" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:09" font="48px"/>
<producer in="0" mlt_service="pango" out="15" text="00:10" font="48px"/>
</playlist>
</mlt>

But I have not found option how to make some area transparent in that MLT stream.