In article <3f6f3cb6@news.povray.org> , Ricky Reusser 
<ple### [at] emailcom>  wrote:

> once you run it through a
> codec like divx, it's only going to make it (more) blocky.

You should note one tiny little bit of information that is good to know, and
applies to all lossy image and image sequence compression algorithms: The
"better" the source material, the better the compression result.

"better" in this context means that anti-aliased image sequences will
compress better, as will blurred ones when you are using DCT-based codecs.
All common codecs that achieve good compression (from JPEG to DV to
MEPG-1,2,4, and all derived ones like divx) are DCT-based.  Even H.264 (aka
MPEG-4 Part 10 or MEPG-4 AVC) uses a DCT-like transformation.  The trick is
that a smooth image results in more effective quantisation and hence better
compression.

If you get "blocky" results, this means your compression settings are simply
to high and too many coefficients are lost during the quantisation process.
In particular when compressing not anti-aliased computer-generated
animations you get compression quality problems ... as do you when feeding
the compressor a noisy captured video sequence.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

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