How to extract a Sound envelope from a .wav file using Python?

Question

I have a sound file which comprise of the instrumental sound. What I want to do is examine the each note of the instrument by extracting from the audio file. Can I use python for doing this or any other open source software that you can recommend to do this. I got the waveform using Audacity. I have attached the image of the sound file and red mark indicate the portion to be extracted. Starting and ending of the envelope. (Only single instrument is played in the audio file).

Answer 1

The thing you want is usually called an envelope detector or envelope follower. Maybe try out the pyo project for this. The analysis module has a few envelope followers available.

Edit: I appear to have misunderstood your question from the title. You want to actually split the notes? I would extract the envelope, then split based on a threshold.