[FFmpeg-user] How to analyse?

[Andrew Marriott]

I need to:

Determine (in ms) the silence between the start of an audio file and the 
start of the audio.
Determine the time (in ms) at the end of the file when the audio level 
drops to -20db

pydub uses ffmpeg for this in the python module: audio_segment but I 
can't figure out how!
Please help. Thanks.