[FFmpeg-devel] ZMBV Improved Motion Estimation

Michael Niedermayer michaelni
Fri May 9 14:51:08 CEST 2008


On Fri, May 09, 2008 at 02:07:59PM +0200, Reimar D?ffinger wrote:
> On Fri, May 09, 2008 at 01:28:30PM +0200, Michael Niedermayer wrote:
> > On Fri, May 09, 2008 at 11:35:03AM +0200, Reimar D?ffinger wrote:
> > > On Fri, May 09, 2008 at 01:04:50AM +0200, Michael Niedermayer wrote:
> > > > > No I don't, actually. I'm glad you came up with a better method. Can you
> > > > > explain how and why it works in 50 words or less? I'm curious.
> > > > 
> > > > 0th order entropy approximation
> > > 
> > > It might be worth noting that it is only quite correct for 16x16 blocks
> > 
> > Fixed for smaller ones.
> 
> Not for those on the border if the resolution is not divisible by the
> block size, which is what I was referring to. Though I think it is now
> a bit better to understand.
> 
> > > and might fail completely for blocks larger than that - just because
> > 
> > smaller blocks seem better on average for the videos i have
> 
> Doesn't surprise me that much, 16x16 seems rather big esp. for generally
> low-resolution videos. Though ZMBV may be more designed for videos with
> large same-colour areas like a commandline, file manager or such.
> Can the block size easily be changed for ZMBV or would that break with all
> existing decoders?

Its stored in the bitstream with each keyframe. So id say it can be changed
without problems.

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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