Sorry but I'm not really clear on what you need to do lightspeed. Not that I'm that familiar with all the newer digital processors that are available today, I'm old school trying to catch up again. But if it's to keep music at certain constant level, programs like Audacity I believe have some sort of limiter built in where if set correctly keeps the volume levels some what contained within a parameter and depending on the volume will compress the peaks and release them as set. So you want to keep a very fast release time as so not to get a breathing effect. But the members that do the uploaded videos probably know much more on what your trying to accomplish.
Just a quick thought but I apologize if I'm way off mark here. Thought I would try anyway.
raybe