On 9/28/22 02:40, Laurent Pinchart wrote:
On Wed, Sep 28, 2022 at 02:37:04AM +0200, Marek Vasut wrote:
On 9/28/22 02:21, Laurent Pinchart wrote:
Hi,
[...]
- /* CSC: BT.601 Full Range RGB to YCbCr coefficients. */
- writel(CSC0_COEF0_A2(0x096) | CSC0_COEF0_A1(0x04c),
+ /* CSC: BT.601 Limited Range RGB to YCbCr coefficients. */
+ writel(CSC0_COEF0_A2(0x081) | CSC0_COEF0_A1(0x042),
lcdif->base + LCDC_V8_CSC0_COEF0);
- writel(CSC0_COEF1_B1(0x7d5) | CSC0_COEF1_A3(0x01d),
+ writel(CSC0_COEF1_B1(0x7da) | CSC0_COEF1_A3(0x019),
lcdif->base + LCDC_V8_CSC0_COEF1);
- writel(CSC0_COEF2_B3(0x080) | CSC0_COEF2_B2(0x7ac),
+ writel(CSC0_COEF2_B3(0x070) | CSC0_COEF2_B2(0x7b6),
lcdif->base + LCDC_V8_CSC0_COEF2);
- writel(CSC0_COEF3_C2(0x795) | CSC0_COEF3_C1(0x080),
+ writel(CSC0_COEF3_C2(0x7a2) | CSC0_COEF3_C1(0x070),
lcdif->base + LCDC_V8_CSC0_COEF3);
- writel(CSC0_COEF4_D1(0x000) | CSC0_COEF4_C3(0x7ec),
+ writel(CSC0_COEF4_D1(0x010) | CSC0_COEF4_C3(0x7ee),
lcdif->base + LCDC_V8_CSC0_COEF4);
writel(CSC0_COEF5_D3(0x080) | CSC0_COEF5_D2(0x080),
lcdif->base + LCDC_V8_CSC0_COEF5);
Would it make sense to use the same coeffs as csc2_coef_bt601_lim in
drivers/media/platform/nxp/imx-pxp.c , since the block is most likely
identical ?
The coefficients in this patch have been computed to distribute the
error in such a way that the sum of all lines stays the same. This
avoids biases and overflow, but it likely makes very little difference
in practice. I'm thus fine with the coefficients from imx-pxp.c.
Would it then make sense to update the coeffs in the pxp driver instead?
Either option works for me.
It could, but I won't be able to easily test it. As the hardware clamps
the calculated value, there's no risk of wraparound, and the difference
in the +/-1 error distribution will not be noticeable, so I'll just copy
the coefficients from imx-pxp.c to ensure coherency.
That works too, thanks !
