[MPlayer-dev-eng] Re: [MP] [PATCH] "turbo" mode

[D Richard Felker III]

On Thu, Sep 16, 2004 at 10:57:37AM +0200, Guillaume POIRIER wrote:
> Hi,
> 
> Le jeu 16/09/2004 à 01:07, D Richard Felker III a écrit :
> > of course qns degrades psnr, that's the whole point of noise shaping.
> > :) it's a perceptual quality optimization, not a psnr optimization, so
> > it's difficult to compare like this.
> > 
> > rich
> 
> Thanks for the enlightenment rich... what's quite surprising is that
> Romain Dolbeau (you know, the altivec guy) wrote a genetic exploration
> software to find what was the best combination of options (PSNR-wise)
> for a given sample of video... and qns was shinning out!
> 
> Ok now, Could you maybe tell me if when the description of qns is:
> "Quantizer noise shaping, reduces ringing artifacts" is it supposed to
> reduce ringing artifacts of the source video (pre-filter), or of the 
> target video (post-filter)?
> I guess it's the target video, but that isn't very clear....

target video. rather than choosing quantization to most closely match
the source video in the psnr sense, it chooses quantization such that
noise (usually ringing) will be masked by similar-frequency content in
the image. or at least that's my understanding...

rich