[MEncoder-users] Cannot achieve better picture quality with MPEG2 - help needed

[Nicolas Hesler]

> As far as I know, mplayer and ffmpeg are using the same libswscale code
> for the conversion. Either way, libswscale is part of the ffmpeg
> project, so you'll need to ask on the ffmpeg-user mailing list.
>
> I don't think I can help you further on this subject.
>
>   

I will take it to the ffmpeg list.  There is definitely a colorspace 
conversion issue. 

It was brought up in a previous thread, although the solution discussed 
there did not help me.

http://thread.gmane.org/gmane.comp.video.mencoder.user/6668

You can easily reproduce the color space conversion problem by taking 
any rgb24 png image sequence, and then encode it with mencoder.  Compare 
the resulting image with the original and you'll see colors change far 
more than they should. It is very apparent if you use a video source 
with large flat color areas, or just a matte color. (I can provide 
samples if anyone wants them) 

I converted the same rgb24 pngs to yuy2 and back again to a bitmap using 
premiere to use as a reference - perceptually the colors were the same.

Although, I know relatively little about color space conversion, could 
the matrices discussed on this avisynth page have something to do with 
the color shifting?

http://avisynth.org/mediawiki/Convert