[MPlayer-users] MPEG4 Low-Motion Quality

[Krzysztof Duchnowski]

On 24.03.2010 02:04, James Board wrote:

> Yes, I read the mencoder documentation, and it told me to use different options for the first and second pass.  Look:
>     http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-mpeg4.html
> 
> The video resolution is 480x480 and the quality of the source MPEG2 is fine.  I'd like to be able to maintain that quality when transcoding to MPEG-4.  In fact, MPEG-4 is supposed to be much better than MPEG-2, so I was hoping to maintain the MPEG-2 quality at 50% of the bit rate.

Yes, but MPEG2 itself encoding in the same way that MPEG4 in a 16x16
matrix basis so compression artifact are here thought you don't see it.
And when you do this 16x16 matrix compression again artifacts grow
exponetionally.

So, before reencoding you must do some filtering.
Adding noise will break 16x16 matrix artifacts but you will have noise
in a picture.

You could add chain of noise-denoise-awarp filtering but you will lose
picture details.
It's not easy to do - reencoding.

You should serach for general movie processing at VideoHELP and Doom9
websites/forums.

-- 
Krzysztof 'DK75' Duchnowski
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