On Tue, May 07, 2019 at 02:35:15PM +0000, Shankar, Uma wrote: > > > >-----Original Message----- > >From: Intel-gfx [mailto:intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Ville > >Syrjälä > >Sent: Tuesday, May 7, 2019 7:37 PM > >To: Sharma, Shashank <shashank.sharma@xxxxxxxxx> > >Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx > >Subject: Re: [PATCH] drm/i915/icl: Handle YCbCr to RGB conversion for > >BT2020 case > > > >On Tue, May 07, 2019 at 06:32:57PM +0530, Shashank Sharma wrote: > >> From: Uma Shankar <uma.shankar@xxxxxxxxx> > >> > >> Currently input csc for YCbCR to RGB conversion handles only > >> BT601 and Bt709. Extending it to support BT2020 as well. > >> > >> Signed-off-by: Uma Shankar <uma.shankar@xxxxxxxxx> > >> Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx> > >> --- > >> drivers/gpu/drm/i915/intel_sprite.c | 24 ++++++++++++++++++++++++ > >> 1 file changed, 24 insertions(+) > >> > >> diff --git a/drivers/gpu/drm/i915/intel_sprite.c > >> b/drivers/gpu/drm/i915/intel_sprite.c > >> index 44aaeac1b2ed..2536e757bec2 100644 > >> --- a/drivers/gpu/drm/i915/intel_sprite.c > >> +++ b/drivers/gpu/drm/i915/intel_sprite.c > >> @@ -433,6 +433,18 @@ icl_program_input_csc(struct intel_plane *plane, > >> 0x9EF8, 0x7800, 0xABF8, > >> 0x0, 0x7800, 0x7ED8, > >> }, > >> + /* > >> + * BT.2020 full range YCbCr -> full range RGB > >> + * The matrix required is : > >> + * [1.000, 0.000, 1.474, > >> + * 1.000, -0.1645, -0.5713, > >> + * 1.000, 1.8814, 0.0000] > >> + */ > >> + [DRM_COLOR_YCBCR_BT2020] = { > >> + 0x7BC8, 0x7800, 0x0, > >> + 0x8928, 0x7800, 0xAA88, > >> + 0x0, 0x7800, 0x7F10, > >> + }, > >> }; > >> > >> /* Matrix for Limited Range to Full Range Conversion */ @@ -461,6 > >> +473,18 @@ icl_program_input_csc(struct intel_plane *plane, > >> 0x8888, 0x7918, 0xADA8, > >> 0x0, 0x7918, 0x6870, > >> }, > >> + /* > >> + * BT.2020 Limited range YCbCr -> full range RGB > >> + * The matrix required is : > >> + * [1.164, 0.000, 1.717, > >> + * 1.138, -0.1873, -0.6504, > >> + * 1.1380, 2.1417, 0.0000] > > > >Where are those 1.138 coming from? > > Hi Ville, > This is the original YCBCR to RGB BT2020 matrix: > { > 1.00000000000, 0.00000000000, 1.47460000000, > 1.00000000000, -0.16455312684, -0.57135312684, > 1.00000000000, 1.88140000000, 0.00000000000 > }; > > We have to convert Limited Range YCbCr to Full Range RGB. Hence we need to apply a scale factor: > yscalefactor = 219.0 * normalizingfactor; > cbcrscalefactor = 224.0 * normalizingfactor; > > /* Scale factors are inverted for LR to FR conversion */ > yscalefactor = 1.0 / yscalefactor; > cbcrscalefactor = 1.0 / cbcrscalefactor; > > This yields the above results. Those are the coefficients for Y, so they should still be the same for all three output channels. igt_color_encoding gives me: |1.1644, 0.0000, 1.6787,| |1.1644,-0.1873,-0.6504,| |1.1644, 2.1418, 0.0000,| Looks like we're also misprogramming the Y pre-offset for the full range YCbCr case. -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
