[MPlayer-dev-eng] [RFC] preliminary x264 encoding help text
lorenm at u.washington.edu
Tue May 3 02:36:01 CEST 2005
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.
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