On 11/05/2015 06:22 PM, 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.
It seems that you are reusing the conversion matrix defined for render
processing.
So it is correct that it is normalized before using the conversion matrix.
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
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