[MPlayer-dev-eng] 3 pass encoding syntax poll

[Guillaume Poirier]

Hi,


On Wed, 9 Feb 2005 14:02:04 -0800 (PST), Loren Merritt
<lorenm at u.washington.edu> wrote:
> On Wed, 9 Feb 2005, Guillaume POIRIER wrote:
> >
> > By the way: How many people actually use lavc's turbo mode? Are you
> > globally happy with it?
> > I do think there still is some room for improvement. When I implemented
> > it, I did a global and frame-by frame PSNR comparison and and noticed
> > very little PSNR difference, but and wasn't able to notice any artefacts
> > on the video which first pass was ran with turbo mode.
> >
> > Can anybody give me some feedbacks about that feature?
> 
> I don't actually use the turbo option, I use 3-pass encoding with manually
> selected settings for each pass. But on reviewing the code, I see:
> 
> > /* Disables diamond motion estimation */
> > lavc_venc_context->pre_dia_size = 0;
> > lavc_venc_context->dia_size = 0;
> 
> dia_size=0 is identical to dia_size=1.
> 
> > lavc_venc_context->mb_decision = 1;
> 
> In my experience, mbd=1 is only slightly faster than mbd=2, and
> significantly lower quality. The only options are mbd=2 or mbd=0:mbcmp=2.
> And the latter works fine for a fast 1st pass.

Ok, I note that and I will update this little piece of code when I
have some time.

Any other feedback welcome.

Regards,
Guillaume