
The code is rather simple: See here:
https://github.com/nzaillian/WaveformWidget (You have a ready-made widget which you can use)
http://stackoverflow.com/questions/1396 ... qbytearray (some Qt code)
Other considerations:
http://supermegaultragroovy.com/2009/10 ... waveforms/
http://stackoverflow.com/questions/1101 ... audio-file
http://stackoverflow.com/questions/1287 ... -file?lq=1
If we'll implement this we're heading to a full-blown multimedia manager...