Re: [PATCH 1/5] d3d9/tests: Clean up yuv_color_test.

[Henri Verbeet]

On 13 February 2014 23:10, Stefan Dösinger <stefan(a)codeweavers.com> wrote:
> +             * Unfortunately different implementations(Windows-NV and Mac-AMD tested) interpret some colors vastly
> +             * differently, so we need a max diff of 18. */
> And actually, is there any chance the "vastly differently" here is
> because of using BT.601 vs. BT.709 coefficients, or not including the
> headroom/footroom scaling + offsets?

[PATCH 1/5] d3d9/tests: Clean up yuv_color_test.

[Stefan Dösinger]

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Am 2014-02-14 20:24, schrieb Henri Verbeet:
> On 13 February 2014 23:10, Stefan Dösinger <stefan(a)codeweavers.com> wrote:
> > +             * Unfortunately different implementations(Windows-NV and Mac-AMD tested) interpret some colors vastly
> > +             * differently, so we need a max diff of 18. */
> > And actually, is there any chance the "vastly differently" here is
> > because of using BT.601 vs. BT.709 coefficients, or not including the
> > headroom/footroom scaling + offsets?
> > Maybe, but I can't look into either driver. If I remember correctly I got the reference values from the GeForce 7 driver on Windows and our shader results match it pretty well (plus / minus 2 or something). Geforce 8+ cards on Windows are off pretty far, and the GL_APPLE_ycbcr_422 support on OSX deviated even more.

I think we're also doing some things wrong with the coefficients in our shader. I read about a common pitfall when handling 8 bit integer chroma that I thought we're falling into, but I don't remember the details.

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