[Ffmpeg-devel] Video compression and quality of codecs.

[Rich Felker]

On Thu, Apr 06, 2006 at 01:47:14AM +0200, Michael Niedermayer wrote:
> Hi
> 
> On Wed, Apr 05, 2006 at 01:22:09PM +0100, Robert Swain wrote:
> [...]
> > > What astonishes me is the quality which was so much better on the WMV
> > 
> > Probably a case of misuse of the h.263 codec if the quality difference is 
> > _huge_ versus the current WMV9. Not to say that WMV9 shouldn't "beat" h.263, 
> > but I wouldn't have thought the difference would be huge. (h.263 has in-loop 
> > filtering doesn't it? Or is that h.263+? Or am I insane? :))
> 
> i think the loop filter is in h.263+ but OBMC is already allowed in h.263 if
> iam not mistaken ...
> and there are alot of things to finetune for best quality (trell, 4mv, obmc, 
> 2pass, ...)
> 
> IIRC some propriatary codecs lie about the framerate and encode at lower
> framerates in high motion cases, IIRC the h.263 reference SW does that too
> so subjective quality should be compared instead of number if possible

No, just compare PSNR but make sure you match the frames up correctly.
With missing frames PSNR will come out around 5 or so, giving a
perfectly fair evaluation to these shitty codecs. :))))

Rich