r200 xvideo gamma curve

[Marco]

Edgar Toernig escreveu:
> Hi,
> 
> I wasn't satisfied with the quality of the xvideo overlay.
> Dark areas had a very low color resolution giving large
> patches of the same color without any details.  At 6.9
> release time a looked at radeon_video and noticed that
> the gamma curve seems to be non-linear at gamma 1.0.  I
> changed it[1] and IMO the picture is much better now - dark
> areas have much more details.
> 
> Is the gamma curve supposed to be non-linear or is it just
> some kind of "make dark areas black" hack?
> 
> Anyway, I would prefer the gamme curve produced by this
> patch at any time:
> 
> --- a/src/radeon_video.c
> +++ b/src/radeon_video.c
> @@ -547,9 +547,9 @@ static GAMMA_CURVE_R100 gamma_curve_r100
>  static GAMMA_CURVE_R200 gamma_curve_r200[8] =
>   {
>         /* Gamma 1.0 */
> -      {0x00000040, 0x00000000,
> -       0x00000040, 0x00000020,
> -       0x00000080, 0x00000040,
> +      {0x00000100, 0x00000000,
> +       0x00000100, 0x00000020,
> +       0x00000100, 0x00000040,
>         0x00000100, 0x00000080,
>         0x00000100, 0x00000100,
>         0x00000100, 0x00000100,
> 
> Ciao, ET.
> 
> [1] As I have no docs, I've no idea what these values
> really mean so I simply tried some settings.
> 
Some info:
http://www.math.ucla.edu/~jimc/xcolor/GammaFAQ.txt
http://www.math.ucla.edu/~jimc/xcolor/
http://insar.stanford.edu/~lharcke/programming/Xcms/

-- 
Marco de Freitas,
NBR para a Internet já! Porque meu navegador não é penico.

http://www.softwarelivre.org/news/2472
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