On Wednesday, May 3, 2017 11:37:52 PM PDT Johnson Lin wrote: > The matrix used for YCbCr to RGB is listed in: > > https://en.wikipedia.org/wiki/YCbCr > > There was an error in converting the offsets from integers to unorm > values: 0.0625=16/256 should be 16.0/255,and 0.5=128.0/256 should be > 128.0/255. With this fix, the CSC result is bit aligned with wikipedia's > conversion result and FFMPeg's result. > --- > 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..4ef81955513e 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, -16.0f / 255.0f))), > + nir_channel(b, nir_fadd(b, u, nir_imm_float(b, -128.0f / > 255.0f)), 0), > + nir_channel(b, nir_fadd(b, v, nir_imm_float(b, -128.0f / > 255.0f)), 0), > nir_imm_float(b, 0.0)); > > nir_ssa_def *red = nir_fdot4(b, yuv, nir_build_imm(b, 4, 32, m[0])); > -- > 1.9.1 > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/mesa-dev >
I scooped up the various tags:
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100854
Reviewed-by: Eric Anholt <e...@anholt.net>
Reviewed-by: Kristian H. Kristensen <hoegsb...@google.com>
and pushed the patch. Thanks for fixing this!
Kristian had suggested adding the problematic value to Piglit's
tests/spec/ext_image_dma_buf_import/sample_yuv.c. If you have time
to write a patch for it, that would be very appreciated. Having a
Piglit test would ensure this doesn't regress in the future.
--Ken
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