Re: [PATCH v5 4/5] docs: Document CLL and Mastering display colorimetry controls

From: Hans Verkuil
Date: Tue Mar 16 2021 - 08:23:46 EST

On 09/02/2021 17:24, Stanimir Varbanov wrote:
> Document Content Light Level and Mastering Display v4l2 colorimetry
> controls.
>
> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
> ---
> .../media/v4l/ext-ctrls-colorimetry.rst | 71 +++++++++++++++++++
> .../media/v4l/vidioc-g-ext-ctrls.rst | 8 +++
> .../media/videodev2.h.rst.exceptions | 2 +
> 3 files changed, 81 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-colorimetry.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-colorimetry.rst
> index 862f78b41b32..a9f206a46175 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-colorimetry.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-colorimetry.rst
> @@ -20,3 +20,74 @@ Colorimetry Control IDs
> The Colorimetry class descriptor. Calling
> :ref:`VIDIOC_QUERYCTRL` for this control will
> return a description of this control class.
> +
> +``V4L2_CID_COLORIMETRY_HDR10_CLL_INFO (struct)``
> + The Content Light Level defines upper bounds for the nominal target
> + brightness light level of the pictures.
> +
> +.. c:type:: v4l2_ctrl_hdr10_cll_info
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: struct v4l2_ctrl_hdr10_cll_info
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 1 1 2
> +
> + * - __u16
> + - ``max_content_light_level``
> + - The upper bound for the maximum light level among all individual
> + samples for the pictures of a coded video sequence, cd/m\ :sup:`2`.

I think 'coded' should be removed. This is equally valid when receiving
uncoded HDMI video, after all.

> + When equal to 0 no such upper bound is present.
> + * - __u16
> + - ``max_pic_average_light_level``
> + - The upper bound for the maximum average light level among the
> + samples for any individual picture of a coded video sequence,

ditto.

> + cd/m\ :sup:`2`. When equal to 0 no such upper bound is present.
> +
> +``V4L2_CID_COLORIMETRY_HDR10_MASTERING_DISPLAY (struct)``
> + The mastering display defines the color volume (the color primaries,
> + white point and luminance range) of a display considered to be the
> + mastering display for the current video content.
> +
> +.. c:type:: v4l2_ctrl_hdr10_mastering_display
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: struct v4l2_ctrl_hdr10_mastering_display
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 1 1 2
> +
> + * - __u16
> + - ``display_primaries_x[3]``
> + - Specifies the normalized x chromaticity coordinate of the color
> + primary component c of the mastering display in increments of 0.00002.
> + For describing the mastering display that uses Red, Green and Blue
> + color primaries, index value c equal to 0 corresponds to the Green
> + primary, c equal to 1 corresponds to Blue primary and c equal to 2
> + corresponds to the Red color primary.
> + * - __u16
> + - ``display_primaries_y[3]``
> + - Specifies the normalized y chromaticity coordinate of the color
> + primary component c of the mastering display in increments of 0.00002.
> + For describing the mastering display that uses Red, Green and Blue
> + color primaries, index value c equal to 0 corresponds to the Green
> + primary, c equal to 1 corresponds to Blue primary and c equal to 2
> + corresponds to Red color primary.
> + * - __u16
> + - ``white_point_x``
> + - Specifies the normalized x chromaticity coordinate of the white
> + point of the mastering display in increments of 0.00002.
> + * - __u16
> + - ``white_point_y``
> + - Specifies the normalized y chromaticity coordinate of the white
> + point of the mastering display in increments of 0.00002.
> + * - __u32
> + - ``max_luminance``
> + - Specifies the nominal maximum display luminance of the mastering
> + display in units of 0.0001 cd/m\ :sup:`2`.
> + * - __u32
> + - ``min_luminance``
> + - specifies the nominal minimum display luminance of the mastering
> + display in units of 0.0001 cd/m\ :sup:`2`.
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> index 8a95ebdd499a..2f6d0539fb93 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> @@ -212,6 +212,14 @@ still cause this situation.
> - ``p_fwht_params``
> - A pointer to a struct :c:type:`v4l2_ctrl_fwht_params`. Valid if this control is
> of type ``V4L2_CTRL_TYPE_FWHT_PARAMS``.
> + * - struct :c:type:`v4l2_ctrl_hdr10_cll_info` *
> + - ``p_hdr10_cll``
> + - A pointer to a struct :c:type:`v4l2_ctrl_hdr10_cll_info`. Valid if this control is
> + of type ``V4L2_CTRL_TYPE_HDR10_CLL_INFO``.
> + * - struct :c:type:`v4l2_ctrl_hdr10_mastering_display` *
> + - ``p_hdr10_mastering``
> + - A pointer to a struct :c:type:`v4l2_ctrl_hdr10_mastering_display`. Valid if this control is
> + of type ``V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY``.
> * - void *
> - ``ptr``
> - A pointer to a compound type which can be an N-dimensional array
> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> index 0ed170c6e720..38b31a9b9580 100644
> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> @@ -147,6 +147,8 @@ replace symbol V4L2_CTRL_TYPE_HEVC_PPS :c:type:`v4l2_ctrl_type`
> replace symbol V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS :c:type:`v4l2_ctrl_type`
> replace symbol V4L2_CTRL_TYPE_AREA :c:type:`v4l2_ctrl_type`
> replace symbol V4L2_CTRL_TYPE_FWHT_PARAMS :c:type:`v4l2_ctrl_type`
> +replace symbol V4L2_CTRL_TYPE_HDR10_CLL_INFO :c:type:`v4l2_ctrl_type`
> +replace symbol V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY :c:type:`v4l2_ctrl_type`
>
> # V4L2 capability defines
> replace define V4L2_CAP_VIDEO_CAPTURE device-capabilities
>

After making the change suggested above, you can add my:

Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>

Regards,

Hans