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    SubjectRe: [V4L] Re: [RFC] alternative kernel multimedia API
    Mark McClelland writes:
    > wrote:
    >> On Mon, 29 Oct 2001, Gerd Knorr wrote:

    >>> You can't. But I don't see why this is a issue: The only thing a
    >>> application can handle easily are controls like contrast/hue where the
    >>> only thing a application needs to do is to map it to a GUI and let the
    >>> user understand and adjust stuff. The other stuff has way to much
    >>> non-trivial dependences, I doubt a application can blindly use new
    >>> driver features.
    >> Have you ever thought that the reason we only use these controls is
    >> because they are the only ones easy to implement now ?
    > What I don't understand is how will your driver implement these controls
    > in a generic V4L3 GUI control app automatically? No matter how powerful
    > the semantic information you give to the app is, it can still only build
    > interfaces from standard GUI components that it already knows about. The
    > app cannot build a gamma curve control on its own. If it could, we
    > wouldn't need programmers anymore :)

    The driver provides this: /proc/v4l3/vid0/


    The very idea of a gamma table is featuritis. Just a single number
    will do for most anyone. You get from 0.01 to 2.55 and "off" with
    just 8 bits.

    If you want to get fancy, I guess you need:

    1 gamma value per primary
    3 tri-stimulus values for each primary ("What color is red?")
    3 tri-stimulus values for the whitepoint (maybe)
    1 black level for each primary

    That is 18 values at most.

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