Start a pipeline:
gst-launch playbin uri=file:///home/thijs/Desktop/mewmew-vorbis-ssa.mkv
On warnings and error's this pipeline will create a dot file. A error can be generated by killing the output window. Now you can transform this dot file to a svg/png/... file. I prefer the use of svg files because the png file from this pipeline is more than 38000 pixels width and crashes my image viewer.
dot -Tsvg -o pipeline.svg 0:00:02.270914892-gst-launch.error.dot
Now you can view your pipeline in inkscape.