Yes, We can. Will do it -----Original Message----- From: Eric Anholt [mailto:e...@anholt.net] Sent: Saturday, April 29, 2017 6:02 AM To: Lin, Johnson <johnson....@intel.com>; mesa-dev@lists.freedesktop.org Cc: Lin, Johnson <johnson....@intel.com> Subject: Re: [Mesa-dev] [PATCH] fix minor error in YUV2RGB matrix used in shader
Johnson Lin <johnson....@intel.com> writes: > The matrix used for YCbCr to RGB is listed in Wiki > https://en.wikipedia.org/wiki/YCbCr; > There is minor error in the matrix constant: 0.0625=16/256 should be > 16.0/255, and 0.5=128.0/256 should be 128.0/255. > Note that conversion from a 0-255 byte number to 0-1.0 float is to > divide by 255 instead of 256. That's we get 255=1.0f. > By the constant change we can see the CSC result is bit aligned with > Wiki conversion result and FFMPeg result. > Otherwise in some situation, there will be one bit difference > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100854 > --- > src/compiler/nir/nir_lower_tex.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/src/compiler/nir/nir_lower_tex.c > b/src/compiler/nir/nir_lower_tex.c > index 352d1499bc8d..385739a56a71 100644 > --- a/src/compiler/nir/nir_lower_tex.c > +++ b/src/compiler/nir/nir_lower_tex.c > @@ -244,9 +244,9 @@ convert_yuv_to_rgb(nir_builder *b, nir_tex_instr *tex, > nir_ssa_def *yuv = > nir_vec4(b, > nir_fmul(b, nir_imm_float(b, 1.16438356f), > - nir_fadd(b, y, nir_imm_float(b, -0.0625f))), > - nir_channel(b, nir_fadd(b, u, nir_imm_float(b, -0.5f)), 0), > - nir_channel(b, nir_fadd(b, v, nir_imm_float(b, -0.5f)), 0), > + nir_fadd(b, y, nir_imm_float(b, -0.0627451f))), > + nir_channel(b, nir_fadd(b, u, nir_imm_float(b, > -0.50196078431f)), 0), > + nir_channel(b, nir_fadd(b, v, nir_imm_float(b, > + -0.50196078431f)), 0), > nir_imm_float(b, 0.0)); Could we use 16.0/255.0 and 128.0/255.0, instead of magic-looking numbers? With that, it will be: Reviewed-by: Eric Anholt <e...@anholt.net> _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
