On 11/05/2015 02:22 AM, Lionel Landwerlin wrote: > On 05/11/15 00:31, Zhao Yakui wrote: >> On 11/04/2015 11:27 PM, Lionel Landwerlin wrote: >>> --- >>> src/shaders/post_processing/gen7/YUV_to_RGB.g4a | 626 >>> ++++++++++++---------- >>> src/shaders/post_processing/gen7/pl2_to_rgbx.g75b | 528 >>> +++++++++--------- >>> src/shaders/post_processing/gen7/pl2_to_rgbx.g7b | 528 >>> +++++++++--------- >>> 3 files changed, 909 insertions(+), 773 deletions(-) >>> >>> diff --git a/src/shaders/post_processing/gen7/YUV_to_RGB.g4a >>> b/src/shaders/post_processing/gen7/YUV_to_RGB.g4a >>> index 24616dc..6af651f 100644 >>> --- a/src/shaders/post_processing/gen7/YUV_to_RGB.g4a >>> +++ b/src/shaders/post_processing/gen7/YUV_to_RGB.g4a >>> @@ -386,34 +386,36 @@ >>> mov (8) fBUFFER_V(0, 0)<1> r[a0.0, 1]<16;8,2>:ub >>> mov (8) fBUFFER_V(1, 0)<1> r[a0.0, 17]<16;8,2>:ub >>> >>> - add (16) fBUFFER_U(0, 0)<1> fBUFFER_U(0, 0)<8;8,1> -128.0f >>> - add (16) fBUFFER_V(0, 0)<1> fBUFFER_V(0, 0)<8;8,1> -128.0f >> >> As far as I know, the value in fBUEER_U/V is still in [0 255] range. >> So I think that it still should be extraced by 128 before it is >> normalized to [0..1]. > > Looking at the green component for example, given the following > coefficients for Y, U and V : > > CY = 1.0 > CU = -0.344 > CV = -0.714 > > This is what the current shader does : > > green = ((Y + (U - 128) * CU + (V - 128) * CV) * 0.0039216) * 255 > > The shader in this patch does this : > > green = (Y * 0.0039216 + (U * 0.0039216 - 128.0 / 255) * CU + (CV * > 0.0039216 - 128.0 / 255) * CV) * 255 > > This looks equivalent to me given that > > 128.0 / 255 ~= 128 * 0.0039216 > > we just distribute the [0..1] normalizing factor earlier.
Ah, that's fine. Thanks, Sean > > It's possible to do what you suggest, but it would require more > instructions. > Maybe I'm missing some precision stuff that is specific to the hardware? > >> >> >>> + mul (16) fBUFFER_Y(0, 0)<1> fBUFFER_Y(0, >>> 0)<1> 0.0039216f >>> + mul (16) fBUFFER_U(0, 0)<1> fBUFFER_U(0, >>> 0)<1> 0.0039216f >>> + mul (16) fBUFFER_V(0, 0)<1> fBUFFER_V(0, >>> 0)<1> 0.0039216f >> > > > > > _______________________________________________ > Libva mailing list > Libva@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/libva > _______________________________________________ Libva mailing list Libva@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libva
