[MPlayer-users] why can not adjust gamma ???

[Guillaume POIRIER]

Hi,

On 12/22/06, kofboy <kofboy at 163.com> wrote:
> mplayer-users,
>
>
>     Hi all, do u found that gamma adjust doesn't work while useing -vo cvidix adn fbdev?
> when i send a conmand into fifo of mplayer, contrast, brightness, hue, saturation can be
> adjusted but gamma can not. Image looks no change both add gamma to 200 or set gamma to zero.

You'd have to use -vf eq2:

       eq2[=gamma:contrast:brightness:saturation:rg:gg:bg:weight]
              Alternative software equalizer that  uses  lookup  tables  (very
              slow),  allowing  gamma correction in addition to simple bright-
              ness and contrast adjustment.  Note that it uses  the  same  MMX
              optimized  code  as -vf eq if all gamma values are 1.0.  The pa-
              rameters are given as floating point values.
                 <0.1-10>
                      initial gamma value (default: 1.0)
                 <-2-2>
                      initial contrast, where negative values result in a neg-
                      ative image (default: 1.0)
                 <-1-1>
                      initial brightness (default: 0.0)
                 <0-3>
                      initial saturation (default: 1.0)
                 <0.1-10>
                      gamma value for the red component (default: 1.0)
                 <0.1-10>
                      gamma value for the green component (default: 1.0)
                 <0.1-10>
                      gamma value for the blue component (default: 1.0)
                 <0-1>
                      The weight parameter can be used to reduce the effect of
                      a high gamma value on bright image areas, e.g. keep them
                      from getting overamplified and just plain white.  A val-
                      ue of 0.0 turns the gamma correction all  the  way  down
                      while 1.0 leaves it at its full strength (default: 1.0).

Guillaume
-- 
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