On Thu, 19 Dec 2024 21:33:37 -0700
Alex Hung <alex.hung@xxxxxxx> wrote:
> From: Harry Wentland <harry.wentland@xxxxxxx>
>
> The BT.709 and BT.2020 OETFs are the same, the only difference
> being that the BT.2020 variant is defined with more precision
> for 10 and 12-bit per color encodings.
>
> Both are used as encoding functions for video content, and are
> therefore defined as OETF (opto-electronic transfer function)
> instead of as EOTF (electro-optical transfer function).
>
> Signed-off-by: Alex Hung <alex.hung@xxxxxxx>
> Signed-off-by: Harry Wentland <harry.wentland@xxxxxxx>
Hi,
why would a display system ever use BT.2020 or BT.709 OETF or its
inverse?
Thanks,
pq
> ---
> drivers/gpu/drm/drm_colorop.c | 2 ++
> include/drm/drm_colorop.h | 19 +++++++++++++++++++
> 2 files changed, 21 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c
> index f3391602a577..665b23900cc0 100644
> --- a/drivers/gpu/drm/drm_colorop.c
> +++ b/drivers/gpu/drm/drm_colorop.c
> @@ -70,6 +70,8 @@ static const struct drm_prop_enum_list drm_colorop_type_enum_list[] = {
> static const char * const colorop_curve_1d_type_names[] = {
> [DRM_COLOROP_1D_CURVE_SRGB_EOTF] = "sRGB EOTF",
> [DRM_COLOROP_1D_CURVE_SRGB_INV_EOTF] = "sRGB Inverse EOTF",
> + [DRM_COLOROP_1D_CURVE_BT2020_INV_OETF] = "BT.2020 Inverse OETF",
> + [DRM_COLOROP_1D_CURVE_BT2020_OETF] = "BT.2020 OETF",
> [DRM_COLOROP_1D_CURVE_PQ_125_EOTF] = "PQ 125 EOTF",
> [DRM_COLOROP_1D_CURVE_PQ_125_INV_EOTF] = "PQ 125 Inverse EOTF",
> };
> diff --git a/include/drm/drm_colorop.h b/include/drm/drm_colorop.h
> index 4084a7438032..83a6bd64d48a 100644
> --- a/include/drm/drm_colorop.h
> +++ b/include/drm/drm_colorop.h
> @@ -55,6 +55,25 @@ enum drm_colorop_curve_1d_type {
> */
> DRM_COLOROP_1D_CURVE_SRGB_INV_EOTF,
>
> + /**
> + * @DRM_COLOROP_1D_CURVE_BT2020_INV_OETF:
> + *
> + * The inverse of &DRM_COLOROP_1D_CURVE_BT2020_OETF
> + */
> + DRM_COLOROP_1D_CURVE_BT2020_INV_OETF,
> +
> + /**
> + * @DRM_COLOROP_1D_CURVE_BT2020_OETF:
> + *
> + * The BT.2020/BT.709 transfer function. The BT.709 and BT.2020
> + * transfer functions are the same, the only difference is that
> + * BT.2020 is defined with more precision for 10 and 12-bit
> + * encodings.
> + *
> + *
> + */
> + DRM_COLOROP_1D_CURVE_BT2020_OETF,
> +
> /**
> * @DRM_COLOROP_1D_CURVE_PQ_125_EOTF:
> *
> --
> 2.43.0
>
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