[vorbis] RC2 worse than RC1 and Beta4

[Gian-Carlo Pascutto]

On Sun, 19 Aug 2001, Attila Padar wrote:

> Gian-Carlo Pascutto wrote:
> >If you are using high bitrates you are just seeing placebo
> >effects. There are changes in the point stereo calculations
> >in CVS, but point stereo is not used in the higher bitrate
> >modes.
>
> 1. Interesting... encoding the same song in 350kbit/s
> bitrate mode I get:
> with the RC2:          273 kbit/s OGG file
> with the latest CVS: 261 kbit/s OGG file
> The sound quality is also different, better in the 2. case.

Argh. I must have misunderstood one of the changes that was
committed. Sorry. I thought a change to one of the noise
calculation functions was just a cleanup but appearently it
wasn't.

> 2. a kind of channel coupling (phase stereo?) is used
> on the high bitrates too (or not?), and I hear that it also
> filters out a part of the high sounds from the music
> and I lose from the stereo effect too a little bit.

It's used up to 192kbps I believe, but not above.

> (I encoded with the non-coupled mode too).
> Maybe it's not totally lossless yet (if I remember well,
> you said that high bitrates use a lossless channel coupling
> mode, but I hear that the coupled and non-coupled songs
> are different (or the 'lossless' doesn't mean this?)).

This is correct. I remember reading about the possibility
of making lossless coupled files produce the exact same
output as uncoupled ones but take less space or something
similar...but I don't know really.

> 3. there is noise masking in RC2 on the high bitrates,
> the beta4 doesn't use it on high bitrates...

:)  I had to fiddle with it in my tuned mode because
I didn't like the results.

> BUT  I will repeat my all tests, and if these were mistakes,
> I will beg your pardon...

Mistake was probably at my end.

> And I don't want to argue with you/developers,
> you know better what you do...

I twiddle with numbers in the vauge illusion I know
what I'm doing ;)


-- 
GCP

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