[PD] gem advanced video keying

[Py Fave]

you need to use glsl shaders to do that efficiently .

first check for existing shaders

you will need a powerful gpu



------------
this is a  lumakey example  (was sent to me by chdh)
--------------
keying.frag

-------------
uniform float R,G,B,K;
uniform sampler2D texture;

void main (void)
{
    float d = 0.;
    vec4 color = texture2D(texture, gl_TexCoord[0].st );

    d+= abs(color.r - R);
    d+= abs(color.g - G);
    d+= abs(color.b - B);

    d*=K;

    color.a = abs(d);

    gl_FragColor = color;

}

------------------------------


2015-08-12 15:13 GMT+02:00 hi via Pd-list <pd-list at lists.iem.at>:
> Dear Pd folk,
>
> I am investigating options to improve chroma keying within pd and gem to use within a theater installation. I need more advanced keying features than seemingly possible with [pix_choma_key], like border corrections and smoother edge transparencies. The best thing i found so far is this:
>
> http://forum.pdpatchrepo.info/topic/2953/neat-chroma-keying/3
>
> very nice, but i would need more a quality like in readymade video mixers
> Did any of you program anything like that?
>
> Also i'm trying to find out, whether a potential setup with a computer with 4 HD-SDI inputs would be capable of keying 2 HD-live-signals at the same time and overlay that over one HD-live-background.
>
> Are there any experiences (hardware and software) from your side, you could share?
>
> I would so much love to make this happen with pd and not with an expensive video mixer i would have to buy.
>
> Any help or ideas are appreciated.
>
> Love to pd,
>
> jonny
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