>-----Original Message----- >From: Ville Syrjälä [mailto:ville.syrjala@xxxxxxxxxxxxxxx] >Sent: Tuesday, May 7, 2019 9:08 PM >To: Shankar, Uma <uma.shankar@xxxxxxxxx> >Cc: Sharma, Shashank <shashank.sharma@xxxxxxxxx>; intel- >gfx@xxxxxxxxxxxxxxxxxxxxx >Subject: Re: [PATCH] drm/i915/icl: Handle YCbCr to RGB conversion for >BT2020 case > >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,| Ok, I used the igt_color_encoding method and able to get values what you got. Will update the matrix. Thanks Ville. >Looks like we're also misprogramming the Y pre-offset for the full range YCbCr case. For full range, I am getting same values as programmed above. Looks ok, can you double check. Regards, Uma Shankar >-- >Ville Syrjälä >Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
