Video Keystone Correction - Help

This is a discussion on Video Keystone Correction - Help ; First off apologies for being a newb, I've not really used Linux for long but this problem is really bugging me and despite loads of searches I've not managed to find any info on what I'm trying to do (guess ...

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Thread: Video Keystone Correction

  1. Video Keystone Correction

    First off apologies for being a newb, I've not really used Linux for
    long but this problem is really bugging me and despite loads of
    searches I've not managed to find any info on what I'm trying to do
    (guess I've been looking in the wrong places).

    I have a comp with Fedora Core 2 installed, it sits in the living room
    and acts as a video recorder / media player / internet server for the
    rest of the house. Recently I've plugged a video projector into the
    second head of the Matrox G400 card (in a true home cinema style),
    however due to the angle it projects at there is a lot of keystone \=/
    on the image. I can partially correct this from the projector by
    playing with the lenses, however beyond a certain point it is
    impossible to keep the entire projected image in focus. Unfortunately
    the LCD panel in the projector has no way of correcting this further
    (i.e. the driver board doesn't support keystone correction)

    What I'm looking for is a way through software on the computer to
    shrink the top of the image whilst leaving the bottom untouched (into
    a trapezium shape) to completely correct the keystone. I realise that
    I'll be losing pixels on the LCD by doing this, however that's an
    acceptable loss for a rectangular image!

    The Gfx card drivers for Linux don't seem to have anything to do this
    (while a lot of windows drivers seem to have this as standard), and as
    of yet I've not found any alternative way of doing it - any
    suggestions?

    Thanks in advance,

    Steve

  2. Re: Video Keystone Correction

    Steve wrote:

    > First off apologies for being a newb, I've not really used Linux for
    > long but this problem is really bugging me and despite loads of
    > searches I've not managed to find any info on what I'm trying to do
    > (guess I've been looking in the wrong places).
    >
    > I have a comp with Fedora Core 2 installed, it sits in the living room
    > and acts as a video recorder / media player / internet server for the
    > rest of the house. Recently I've plugged a video projector into the
    > second head of the Matrox G400 card (in a true home cinema style),
    > however due to the angle it projects at there is a lot of keystone \=/
    > on the image. I can partially correct this from the projector by
    > playing with the lenses, however beyond a certain point it is
    > impossible to keep the entire projected image in focus. Unfortunately
    > the LCD panel in the projector has no way of correcting this further
    > (i.e. the driver board doesn't support keystone correction)
    >
    > What I'm looking for is a way through software on the computer to
    > shrink the top of the image whilst leaving the bottom untouched (into
    > a trapezium shape) to completely correct the keystone. I realise that
    > I'll be losing pixels on the LCD by doing this, however that's an
    > acceptable loss for a rectangular image!
    >
    > The Gfx card drivers for Linux don't seem to have anything to do this
    > (while a lot of windows drivers seem to have this as standard), and as
    > of yet I've not found any alternative way of doing it - any
    > suggestions?
    >
    > Thanks in advance,
    >
    > Steve


    I don't remember keystone corrections for *any* graphics
    card as standard. Damn difficult to synthesize
    video waveforms to do that!!!

    You need to mount the project further high up and
    project it properly, or tilt the screen to match
    the projection angle.


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