[vorbis] APPLAUD.WAV problems

[MARK JAMES HETHERINGTON]

Is it posible to switch between lossy and lossless encoding per packet? 
Or does the whole stream have to be one or the other? Perhaps packets 
with problematic stereo images could be encoded losslessly (at a 
bitrate penalty), while saving bits on others?

----- Original Message -----
From: Gian-Carlo Pascutto <gcp at sjeng.org>
Date: Friday, February 15, 2002 9:50 am
Subject: Re: [vorbis] APPLAUD.WAV  problems

> ----- Original Message -----
> From: "Bostjan" <00 at email.si>
> To: "_Ogg" <vorbis at xiph.org>
> Sent: Thursday, February 14, 2002 6:23 PM
> Subject: Re: [vorbis] APPLAUD.WAV problems
> 
> 
> > <<<<<<<<
> > ----- Original Message -----
> > From: "Gian-Carlo Pascutto" <gcp at sjeng.org>
> > To: <vorbis at xiph.org>
> > Sent: Thursday, February 14, 2002 5:01 PM
> > Subject: Re: [vorbis] APPLAUD.WAV problems
> > > The ironic fact is that Gian-Carlo seems to have noticed this
> > > lossy-stereo-coding problem already and has tuned his OGG 
> encoders to
> > > eliminate it.
> > I didn't eliminate the lossy-stereo-coding problem; I eliminated the
> > lossy stereo modes :)
> > >>>>>>>>
> >
> > It isn't at all a bad idea. Is it possible to add a switch to 
> oggenc that
> > eliminates the lossy stereo modes?
> 
> It's possible and I presume it will be added in one of the next 
> versions.
> Personally, I am _against_ this idea. The advantages
> and disadvantages of allowing the user to control the coupling have
> been discussed before, and you should be able to dig them up via
> the archives.
> 
> > <<<<<<<
> > Then again, applaud is a known problem
> > case for encoders, and it might just as well be the encoder is doing
> > things perfectly everywhere else. I don't really like getting 
> impressions> by using that kind of clips, as I think they are 
> giving a skewed view.
> > >>>>>>>>
> >
> > I agree, but many songs contain applauds and a premium encoder 
> such as OGG
> > shouldn't produce such CLEARLY EVIDENT artifacts.
> 
> There is nothing that says that Ogg currently fails on all applaud 
> sounds.Moreover, it handles it fine with a higher quality setting, 
> and I would
> imagine
> that the applaud sounds are not exactly the ones where good 
> reproductionis of the utmost importance!
> 
> This is a minor problem that can likely be tuned out. It's not the 
> end of
> the world.
> 
> > You are right. But if a person hears such an evident artefact on 
> a common
> > sound like an applaud, he would think again before re-using the 
> encoder> below -q 5.
> 
> Not necessarily a bad thing. Expecting transparency at sub-150 
> bitratesis daydreaming, no matter what codec you use. I would be 
> pretty happy
> if we can get transparency(*) at around 170kbps!
> 
> > <<<<<<
> > I'm not trying to downplay that RC3 might have problems on applaud,
> > I'm just writing this overly long mail because yours left (at 
> least for
> me)
> > the impression that GT2 at 160kbps gives better results than RC3 -q5.
> > I certainly doub't that is true for the general case, see my 
> answer to
> > the next question.
> > >>>>>>
> >
> > I'm sorry to have created confusion. What I actually ment was 
> that GT2 -b
> > 128 compresses APPLAUD.WAV better than RC3 oggenc -q 4.9 at the same
> > bitrate.
> 
> Okay, then this is very likely a stereo coupling problem...GT2 at 128kbps
> is essentially RC2 with lossless channel coupling.
> 
> > Thank you for you effort. I really enjoy using OGG and I often 
> reccomendit
> > to my friends. I posted this just to report a flaw and help OGG 
> become> better.
> 
> You're welcome, thanks!
> 
> (*) this is tricky thing to define. When I talk about it I 
> essentially mean
> 'good
> enough so that even trained listeners will have trouble coming up 
> with a
> clip
> they can ABX'
> 
> --
> GCP
> 
> 
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