[MPlayer-dev-eng] synch to x264 r50 / mencgen

[Guillaume POIRIER]

Hi,
Le mer 29/09/2004 à 23:07, Loren Merritt a écrit :
> On Wed, 29 Sep 2004, Guillaume POIRIER wrote:
> > In the attempt to provide users the best possible documentation, what is
> > suppose to happen is no scene-cut detection is done?
> > Are I-frames only inserted each every "keyint" frames?
> 
> Yes.

The updated attached patch features that explanation.


> Other nitpicks with the current mencgen:
> It has two entries for cabacidc=1, and none for cabacidc=2. (Not that I've 
> ever seen cabacidc=2 help.)
> It doesn't try frameref>3. I see noticeable improvements all the way up 
> to frameref=15.
> 
> > I'll let this test run during the whole night, it's currently à the 12th
> > step of 15 encodes each, so that's 180 different combinations that have
> > been explored already... Pffiou! That really eats up LOTS of CPU time!
> 
> Heh. I have here a run of 5000 lavc option sets for each of 3 source 
> videos...

Hum, I wasn't pretending that I was running more combinations than you
(I have just one machine to play with), it's just that quite frankly,
I'm pretty amazed by the fact that mencgen allows a joe-user "brain
dead" exploration of encoding options...

The nice thing about mencgen is that the genetic algorithm seem to
converge "fairly fast" (after 10 runs) to an optimal combination, so
that there's no need to run hundreds more.

BTW, my tonight run gave me the following results:
[x264] Best Result (17): [psnr, bframes=1, cabac, null, deblock, null,
null, frameref=3, fullinter, idrint=3, keyint=250, qblur=0.5, qcomp=0.6,
subq=5] [PSNR: Y=46.58, Cb=45.95, Cr=45.89, All=46.34863669101155  in
257.94 seconds] {UNCHANGED since 9}

[x264] Faster within 1.0% (17): [psnr, bframes=1, cabac, null, deblock,
deblockalpha=1, null, frameref=3, nofullinter, idrint=2, keyint=250,
qblur=0.5, qcomp=0.6, subq=3] [PSNR: Y=46.4, Cb=45.87, Cr=45.82,
All=46.20698515904536  in 163.67 seconds]


Regards,

Guillaume

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