[MPlayer-dev-eng] comprehensive lavcopts test - in progress.

Roman Gaufman hackeron at dsl.pipex.com
Tue Jun 15 18:39:26 CEST 2004


Thanks, I'll look at gnuplot. I am already encoding at 3 bitrates (500kbit, 
9000kbit and 1600kbit). What quantizers do you recommend? 

Wouldnt just using pass2 encoding be the best as thats what will be used for 
the final encoding? ..  I hear some args do not work nearly as well without 
pass2, even on a 30 second encoding.. is this true?

On Tuesday 15 June 2004 14:47, Michael Niedermayer wrote:
> Hi
>
> On Tuesday 15 June 2004 15:20, Jan Knutar wrote:
> > > 1) PSNR ratio to filesize is also very important, not just PSNR
> > > value, you should provide a difference in filesize as well (if any)
> >
> > For comparing PSNR ratio vs filesize, I think the only sane way is to
> > use vqscale encoding, not 2 pass vbitrate encoding.
> >
> > It is my understanding that if you would compare file size AND psnr,
> > WHILE using vbitrate 2 pass, all the adjusting of PSNR scores based on
> > fielsize will just be random ratecontrol deviation noise.
> >
> > Could someone PLEASE explain this more clearer than I did? Or tell me if
> > I'm wrong :-)
>
> the correct way to compare is to plot PSNR vs. filesize curves but u need
> to encode at several bitrates or quantizers to do this
>
> btw, such curves can easily be drawn with gnuplot
>
> [...]




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