diff options
Diffstat (limited to 'Documentation/media/uapi/v4l/pixfmt-006.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/pixfmt-006.rst | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/Documentation/media/uapi/v4l/pixfmt-006.rst b/Documentation/media/uapi/v4l/pixfmt-006.rst index a9890ff6038b..7ae7dcf73f63 100644 --- a/Documentation/media/uapi/v4l/pixfmt-006.rst +++ b/Documentation/media/uapi/v4l/pixfmt-006.rst @@ -19,9 +19,16 @@ colorspace field of struct :c:type:`v4l2_pix_format` or struct :c:type:`v4l2_pix_format_mplane` needs to be filled in. -.. note:: +.. _hsv-colorspace: - The default R'G'B' quantization is full range for all +On :ref:`HSV formats <hsv-formats>` the *Hue* is defined as the angle on +the cylindrical color representation. Usually this angle is measured in +degrees, i.e. 0-360. When we map this angle value into 8 bits, there are +two basic ways to do it: Divide the angular value by 2 (0-179), or use the +whole range, 0-255, dividing the angular value by 1.41. The enum +:c:type:`v4l2_hsv_encoding` specifies which encoding is used. + +.. note:: The default R'G'B' quantization is full range for all colorspaces except for BT.2020 which uses limited range R'G'B' quantization. @@ -123,6 +130,24 @@ needs to be filled in. +.. c:type:: v4l2_hsv_encoding + +.. tabularcolumns:: |p{6.5cm}|p{11.0cm}| + +.. flat-table:: V4L2 HSV Encodings + :header-rows: 1 + :stub-columns: 0 + + * - Identifier + - Details + * - ``V4L2_HSV_ENC_180`` + - For the Hue, each LSB is two degrees. + * - ``V4L2_HSV_ENC_256`` + - For the Hue, the 360 degrees are mapped into 8 bits, i.e. each + LSB is roughly 1.41 degrees. + + + .. c:type:: v4l2_quantization .. tabularcolumns:: |p{6.5cm}|p{11.0cm}| @@ -136,7 +161,7 @@ needs to be filled in. * - ``V4L2_QUANTIZATION_DEFAULT`` - Use the default quantization encoding as defined by the colorspace. This is always full range for R'G'B' (except for the - BT.2020 colorspace) and usually limited range for Y'CbCr. + BT.2020 colorspace) and HSV. It is usually limited range for Y'CbCr. * - ``V4L2_QUANTIZATION_FULL_RANGE`` - Use the full range quantization encoding. I.e. the range [0…1] is mapped to [0…255] (with possible clipping to [1…254] to avoid the |