Add an overshoot output for module LoudnessMeter

[DarkRedman]

This new output that exposes overshoot value (momentaryLufs - targetValue), so an external module could dynamically adjust volume.

P.S : I experiment with your module and my WIP module PID Controller.

[victorkashirin]

@DarkRedman thank you for the contribution! I'll cleanup my backlog and will work on integrating that.

Few things:

1. Most likely this will be implemented as expander - this way it would be possible to add some controls for sensitivity and modes (see below)
2. Which external module you controlled with it? One thing to consider: if you control VCA and use momentary - target, it effectively works as compressor with sharp attack and decay and very high compression ratio. It might be worth to allow using short-term or integrated, especially latter, since it captures overall loudness over recent/long period of time.

[DarkRedman]

Sorry, since last time I read your response but forgot to post a response.

1. I think that to implement it as an expander is a great idea, and for example to have a switch for thoses options :

• momentary
• short term
• long term

2. I used it with my PID controller I wrote but not yet published (Work In Progress), mimicking a real PID controller but for musical purposes.

https://en.wikipedia.org/wiki/Proportional%E2%80%93integral%E2%80%93derivative_controller