Python Scripting [2A]; Syncing a video and music directory tree

Having completed our first scripting task involved XML extraction and copying files, the next task to be scripted in Python will be the process of extracting audio from our collection of music video tracks and syncing it into a directory tree.
The actual steps needed are:
  1. Compare two directory tree, one for video and one for music
  2. Where a music track is missing, extract the audio from a video clip in the video directory tree and save it into the music directory tree.

So it can be described in a couple of steps but the breakdown of tasks may be a little more complex.

The task involves calling ffmpeg to perform the audio extraction and the parameters may vary depending on the type of source file.  
So we will see how things proceed on this one.