[vorbis-dev] vorbis-utils features ;)

[Gregory Maxwell]

On Fri, Mar 23, 2001 at 12:54:07PM +0200, Beni Cherniavsky wrote:
> > Currently vorbis does a very smart, but consertive thing:
> > It doesn't know how loud you will be playing a file, so it can't assume it
> > can just throw out or quantize the hell out of quiet stuff. However, it does
> > know that the loudest sound within a sample ill not be louder then a certian
[snip]
> This looks a Good Idea - add an option to the encoder to assume a "limited
> knob reaction speed".  The way I understand it now, it takes the maximum
> value of the current block as the reference - the option would say to take
> the maximum value over the last T msecs...  Lookahead is probably
> meaningless (OK, his ears are going to hurt badly 15 msecs from now but he
> doesn't know that yet and will be upset at Vorbis' low dynamic range which
> was the last thing he heard before becoming deaf :-).

Talked to Monty. Found out I was wrong: Vorbis already has a time-dampened
peak value... I thought I was being clever, but Monty of course, he was
already cleaver first. :)

'Lookahead' might not be totally stupid, after all if you've got it cranked
so loud that the peak is 16db over your threshold of pain, you aren't really
going to care if the super-quiet first 10 seconds where a little less then
perfect. Unfortunately the fact that it would pretty much require a two pass
encoder relegates this optimization to a future encoder which is already
multipass for other reasons.

> All this is assuming one won't do strong band-filtering to listen closely
> to quiet frequencies of the sound but Vorbis assumes this already.  
> People should be punished for certain quality-problem-hunting listening
> habits ;-)

Doing that sort of thing would make sence... providing you where evaluating
the quality of an audio system to be used by aliens.

:)

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