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Posted: **15 Aug 2013 15:28**

We have the case where we have one desktop with two nVidia cards and four monitors where we are trying to play 48 vlc video windows. It appears that when using vout=opengl, that only the first graphics card is used for acceleration. I have been trying to write a patch to allow a custom vlc command line argument to specify the graphics card to use, such as

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--nvidia-affinity=1

I have been playing with the following code

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int nVidiaAffinity = var_InheritInteger(vd, "nvidia-affinity");
if (nVidiaAffinity >= 0) { 
    HGPUNV GpuMask[2];
    HGPUNV hGPU;
    GpuMask[0] = NULL;
    GpuMask[1] = NULL;
    if (wglEnumGpusNV(nVidiaAffinity , &hGPU)) {
        GpuMask[0] = hGPU;
        sys->hGLDC  = wglCreateAffinityDCNV(GpuMask);
    }
}

Everything compiles but when I go to run, the wgl extension function pointers are all NULL.

Any thoughts on what I may be doing wrong? Any one interested in looking at this development? We might be willing to pay for this feature to be developed and contributed back to vlc.
Thanks, David

Posted: **15 Aug 2013 16:09**

Are you sure you shouldn't get those wglEnumGpusNV with vlc_gl_GetProcAddress ?

Posted: **15 Aug 2013 18:07**

According to wglew.h and glwin32.c the function call to find the procedure pointers is

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wglGetProcAddress

Is this correct?

Posted: **15 Aug 2013 18:41**

No. Use the vlc one.

The VideoLAN Forums

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