[x264-devel] Re: 1/4 pixel resolution

[leon jorgunsen]

Guys,

You can perform 1/8-pel motion compensation if you use bi-predicted blocks, the same reference picture in lists 0 and 1, and a 1/4-pel motion vector difference between the blocks. The interpolation of the two 1/4-pel positions is a 1/8-pel position.
You can also imagine greater resolution by combining bi-prediction and weighted prediction...

--Leon

> De: Tuukka Toivonen <tuukkat at ee.oulu.fi>
> A: x264-devel at videolan.org
> Objet: [x264-devel] Re: 1/4 pixel resolution
> Date: Fri, 12 Aug 2005 12:13:07 +0300 (EEST)

> On Fri, 12 Aug 2005, leon jorgunsen wrote:
> 
> >You can even perform 1/8-pel motion compensation...
> 
> But not in H.264. Except possibly for chroma
> (not sure how it works, but if you get 1/4 position
> for luma, then you need to linearly interpolate 4:2:0 chroma
> for 1/8 chroma pixel position).
> 
> 1/8 luma interpolation was suggested for H.264
> during the standardization but rejected before
> final version.
> 
> I think even 1/3 pixel ME/MC was suggested at some stage.
> 
> Laurent's suggestion to emulate 1/8 MC with B-frames
> was fabulous. When do we get that into x264? ;)
> 
> -- 
> This is the x264-devel mailing-list
> To unsubscribe, go to: <a href=http://developers.videolan.org/lists.html>http://developers.videolan.org/lists.html</a>

Protek-on: CaraMail met en oeuvre un nouveau Concept de Sécurité Globale - www.caramail.com