Also it's worth mentioning that gstreamer is far more superior than ffmpeg, with its bindings, plugin architecture, control over stream (valves, tees, etc) and overall quality of code.

I would hazard a guess that a plurality, by a large margin, of ffmpeg invocations are something on the level of

   ffmpeg -i input.mov output.mp4
for which you don't really need any of those things :)