[MEncoder-users] Experiences of video encoding

[Nicolas George]

Le sextidi 6 germinal, an CCXV, Vladimir Mosgalin a écrit :
> The second phase  would be filling these empty lists with data? Or at
> least some of them should be filled already? I don't see any reference,
> so I don't really get it. Or maybe there is data, but this page isn't
> compatible with firefox?
> 
> Besides empty list, I also don't see any images

I do not understand what lists you are talking about. I did not publish the
numeric values of my tests, only the curves.

As for the curves, then, there is obviously some problem between my code and
your browser. Do you have an extension that blocks iframes? Can you see the
examples on <URL: http://www.croczilla.com/svg/samples/ >? Can you see the
curves directly, <URL:
http://www.eleves.ens.fr/home/george/info/video_quality/expl-bitrate-correl-amelie.svg
 > for example?

I will try to write something to manually disable the fancy SVG curves when
they do not work. In the meantime, you can just disable javascript when
loading the page: the default version uses plain bitmap images.

> I wonder why have you used vhq=4 xvid option - it's slower than vhq=1,
> but are you really sure it's better? I don't really remember why, but
> somehow I never liked it and used only vhq=1.

Does it actually decrease quality? For the first phase, I almost did not
care about encoding time, and I just picked the options that, according to
the documentation, were very likely to increase quality. Examining carefully
each option is the task of the second phase.

> PS congrats on picking Amélie for this test - in pre-x264 era, I never
> managed to encode this (wonderful) dvd while keeping the picture at
> perfect level - it required insane bitrates at small quantizer values.
> Wonder if x264 can do this.

Unfortunately, x264 does not make miracles. It performs better than lavc or
XviD, but it still requires, for the same quality, twice the bitrate it
requires for Matrix. I do not really understand the cause; maybe some sort
of grain in the image.

Regards,

-- 
  Nicolas George
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