[MPlayer-dev-eng] [PATCH] audio filter volnorm2 - two-pass audio normalizer

[Vladislav Naumov]

> > volnorm2 - two-pass audio normalizer.
> > This filter should become a 2-pass audio normalizer:
> > on first pass, it should analyze audio for peak value
> > and store it in file, and on second act as "volume",
> > amplifying sound.
> > Currently only 1st pass is implemented.
> > It can be used to find peak/gain values.
> > Something like "cropdetect" filter, but for sound.
> 
> I'm against this if it's left as a peak normalizer. Peak normalization
> is always incorrect and morons keep asking for it, so they'll do it
> more if a filter is available and ruin the sound. Instead it should be
> RMS normalization.

Well, it seems I'm one of those morons :-)
I am not a sound processing guru, I'm just trying to guess how much can I
amplify sound before encoding. Peak detection is very simple and it for
sure won't cause any sound clipping.
So, as far as I see volnorm2 gives fast and safe answer for stated
question.

Ruin a sound? What do you mean?
You always have a source sound, won't you?

And what I like in volnorm2 the most - and this is the point!
- I understand how it works :-)

Anyway, what is an RMS normalization?
How it will be better then peak detection?
(Let me guess: it will normalize more agressively?)
Should I read http://en.wikipedia.org/wiki/Root_mean_square ?
What else should I read?
I want to make volnorm2 as good as I can.