[FFmpeg-user] visualising Filtergraphs

[Tim Nicholson]

I am trying to use graph2dot, as per

http://ffmpeg.org/ffmpeg.html#graph2dot

but failing miserably.
For example:-

> echo "scale=iw/2:ih/2:interl=1" | \
graph2dot -o graph.tmp && dot -Tpng graph.tmp \
-o graph.png && display graph.png
Input pad "default" for the filter "Parsed_scale_0" of type "scale" not
connected to any source

I have tried adding -i infile and -vf in front, and then it complains
about "No such filter: -vf" etc.

The actual filter string works fine in a real ffmpeg command line.

I'm obviously missing something simple, but could anyone enlighten me
please?
-- 
Tim