On 09/11/2020 18:31, Stanimir Varbanov wrote: > Document Content light level and Mastering display colour volume. > > Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx> > --- > .../media/v4l/ext-ctrls-codec.rst | 61 +++++++++++++++++++ > 1 file changed, 61 insertions(+) > > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst > index ce728c757eaf..39d0aab5ca3d 100644 > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst > @@ -4382,3 +4382,64 @@ enum v4l2_mpeg_video_hevc_size_of_length_field - > - Selecting this value specifies that HEVC slices are expected > to be prefixed by Annex B start codes. According to :ref:`hevc` > valid start codes can be 3-bytes 0x000001 or 4-bytes 0x00000001. > + > +``V4L2_CID_MPEG_VIDEO_HEVC_CLL_INFO (struct)`` > + The Content Light Level defines upper bounds for the nominal target > + brightness light level of the pictures. > + > +.. c:type:: v4l2_ctrl_hevc_cll_info > + > +.. cssclass:: longtable > + > +.. flat-table:: struct v4l2_ctrl_hevc_cll_info > + :header-rows: 0 > + :stub-columns: 0 > + :widths: 1 1 2 > + > + * - __u16 > + - ``max_content_light_level`` > + - An upper bound on the maximum light level among all individual > + samples for the pictures of coded video sequence, cd/m2. > + * - __u16 > + - ``max_pic_average_light_level`` > + - An upper bound on the maximum average light level among the > + samples for any idividual picture of coded video sequence, cd/m2. idividual -> individual In the CTA-861-G spec value 0 is used to indicate that this information is not present. How is that handled here? Can it be 0 as well in an HEVC stream? Same for the next control. > + > +``V4L2_CID_MPEG_VIDEO_HEVC_MASTERING_DISPLAY (struct)`` > + The mastering display defines the colour volume (the colour primaries, > + white point and luminance range) of a display considered to be the > + mastering display for current video content. > + > +.. c:type:: v4l2_ctrl_hevc_mastering_display > + > +.. cssclass:: longtable > + > +.. flat-table:: struct v4l2_ctrl_hevc_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 colour > + primary component of the mastering display. CTA-861-G defines this as: "coded as unsigned 16-bit values in units of 0.00002, where 0x0000 represents zero and 0xC350 represents 1.0000." Is that true here as well? If so, then this should be documented because "normalized x chromaticity coordinate" doesn't say anything meaningful. > + * - __u16 > + - ``display_primaries_y[3]`` > + - Specifies the normalized y chromaticity coordinate of the colour > + primary component of the mastering display. > + * - __u16 > + - ``white_point_x`` > + - Specifies the normalized x chromaticity coordinate of the white > + point of the mastering display. > + * - __u16 > + - ``white_point_y`` > + - Specifies the normalized y chromaticity coordinate of the white > + point of the mastering display. > + * - __u32 > + - ``max_luminance`` > + - Specifies the nominal maximum display luminance of the mastering > + display. In CTA-861-G this is in 1 cd/m^2 units. > + * - __u32 > + - ``min_luminance`` > + - specifies the nominal minimum display luminance of the mastering > + display. And this in units of 0.0001 cd/m^2. Regards, Hans
