[MPlayer-dev-eng] [RFC] preliminary x264 encoding help text

[Loren Merritt]

On Mon, 2 May 2005, Ken Johanson wrote:

> I'm trying to figure out if the weighted prediction is pretty much as good as 
> it gets; I've seen several clips that don't encode gracefully when there is 
> luminance fluctuation caused by camera auto-iris.. Having tried multiple 
> other AVC encoders and getting the same results, I'm wondering if this is a 
> limitation of the AVC design/spec (the same clips encodes with much fewer 
> artifacts when using another 'popular' codec).

x264 supports weighted prediction only in B-frames (because that decision 
is easy to make). I have implemented all the required code for weighting 
in P-frames, but with my simple heuristic (non-motion-compensated least 
squares fit) it doesn't help compression noticably in any of the videos 
I've fed it (other than some digitally perfect fade-ins I created).

Of course, the real solution would be to fix the luminance values before 
encoding, but I don't think that's possible in mencoder.

--Loren Merritt