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diff --git a/Documentation/media/uapi/v4l/pixfmt-006.rst b/Documentation/media/uapi/v4l/pixfmt-006.rst new file mode 100644 index 000000000..987b9a8a9 --- /dev/null +++ b/Documentation/media/uapi/v4l/pixfmt-006.rst @@ -0,0 +1,288 @@ +.. -*- coding: utf-8; mode: rst -*- + +**************************** +Defining Colorspaces in V4L2 +**************************** + +In V4L2 colorspaces are defined by four values. The first is the +colorspace identifier (enum :ref:`v4l2_colorspace <v4l2-colorspace>`) +which defines the chromaticities, the default transfer function, the +default Y'CbCr encoding and the default quantization method. The second +is the transfer function identifier (enum +:ref:`v4l2_xfer_func <v4l2-xfer-func>`) to specify non-standard +transfer functions. The third is the Y'CbCr encoding identifier (enum +:ref:`v4l2_ycbcr_encoding <v4l2-ycbcr-encoding>`) to specify +non-standard Y'CbCr encodings and the fourth is the quantization +identifier (enum :ref:`v4l2_quantization <v4l2-quantization>`) to +specify non-standard quantization methods. Most of the time only the +colorspace field of struct :ref:`v4l2_pix_format <v4l2-pix-format>` +or struct :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` +needs to be filled in. + +.. 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. + + +.. _v4l2-colorspace: + +.. flat-table:: V4L2 Colorspaces + :header-rows: 1 + :stub-columns: 0 + + + - .. row 1 + + - Identifier + + - Details + + - .. row 2 + + - ``V4L2_COLORSPACE_DEFAULT`` + + - The default colorspace. This can be used by applications to let + the driver fill in the colorspace. + + - .. row 3 + + - ``V4L2_COLORSPACE_SMPTE170M`` + + - See :ref:`col-smpte-170m`. + + - .. row 4 + + - ``V4L2_COLORSPACE_REC709`` + + - See :ref:`col-rec709`. + + - .. row 5 + + - ``V4L2_COLORSPACE_SRGB`` + + - See :ref:`col-srgb`. + + - .. row 6 + + - ``V4L2_COLORSPACE_ADOBERGB`` + + - See :ref:`col-adobergb`. + + - .. row 7 + + - ``V4L2_COLORSPACE_BT2020`` + + - See :ref:`col-bt2020`. + + - .. row 8 + + - ``V4L2_COLORSPACE_DCI_P3`` + + - See :ref:`col-dcip3`. + + - .. row 9 + + - ``V4L2_COLORSPACE_SMPTE240M`` + + - See :ref:`col-smpte-240m`. + + - .. row 10 + + - ``V4L2_COLORSPACE_470_SYSTEM_M`` + + - See :ref:`col-sysm`. + + - .. row 11 + + - ``V4L2_COLORSPACE_470_SYSTEM_BG`` + + - See :ref:`col-sysbg`. + + - .. row 12 + + - ``V4L2_COLORSPACE_JPEG`` + + - See :ref:`col-jpeg`. + + - .. row 13 + + - ``V4L2_COLORSPACE_RAW`` + + - The raw colorspace. This is used for raw image capture where the + image is minimally processed and is using the internal colorspace + of the device. The software that processes an image using this + 'colorspace' will have to know the internals of the capture + device. + + + +.. _v4l2-xfer-func: + +.. flat-table:: V4L2 Transfer Function + :header-rows: 1 + :stub-columns: 0 + + + - .. row 1 + + - Identifier + + - Details + + - .. row 2 + + - ``V4L2_XFER_FUNC_DEFAULT`` + + - Use the default transfer function as defined by the colorspace. + + - .. row 3 + + - ``V4L2_XFER_FUNC_709`` + + - Use the Rec. 709 transfer function. + + - .. row 4 + + - ``V4L2_XFER_FUNC_SRGB`` + + - Use the sRGB transfer function. + + - .. row 5 + + - ``V4L2_XFER_FUNC_ADOBERGB`` + + - Use the AdobeRGB transfer function. + + - .. row 6 + + - ``V4L2_XFER_FUNC_SMPTE240M`` + + - Use the SMPTE 240M transfer function. + + - .. row 7 + + - ``V4L2_XFER_FUNC_NONE`` + + - Do not use a transfer function (i.e. use linear RGB values). + + - .. row 8 + + - ``V4L2_XFER_FUNC_DCI_P3`` + + - Use the DCI-P3 transfer function. + + - .. row 9 + + - ``V4L2_XFER_FUNC_SMPTE2084`` + + - Use the SMPTE 2084 transfer function. + + + +.. _v4l2-ycbcr-encoding: + +.. flat-table:: V4L2 Y'CbCr Encodings + :header-rows: 1 + :stub-columns: 0 + + + - .. row 1 + + - Identifier + + - Details + + - .. row 2 + + - ``V4L2_YCBCR_ENC_DEFAULT`` + + - Use the default Y'CbCr encoding as defined by the colorspace. + + - .. row 3 + + - ``V4L2_YCBCR_ENC_601`` + + - Use the BT.601 Y'CbCr encoding. + + - .. row 4 + + - ``V4L2_YCBCR_ENC_709`` + + - Use the Rec. 709 Y'CbCr encoding. + + - .. row 5 + + - ``V4L2_YCBCR_ENC_XV601`` + + - Use the extended gamut xvYCC BT.601 encoding. + + - .. row 6 + + - ``V4L2_YCBCR_ENC_XV709`` + + - Use the extended gamut xvYCC Rec. 709 encoding. + + - .. row 7 + + - ``V4L2_YCBCR_ENC_SYCC`` + + - Use the extended gamut sYCC encoding. + + - .. row 8 + + - ``V4L2_YCBCR_ENC_BT2020`` + + - Use the default non-constant luminance BT.2020 Y'CbCr encoding. + + - .. row 9 + + - ``V4L2_YCBCR_ENC_BT2020_CONST_LUM`` + + - Use the constant luminance BT.2020 Yc'CbcCrc encoding. + + - .. row 10 + + - ``V4L2_YCBCR_ENC_SMPTE_240M`` + + - Use the SMPTE 240M Y'CbCr encoding. + + + +.. _v4l2-quantization: + +.. flat-table:: V4L2 Quantization Methods + :header-rows: 1 + :stub-columns: 0 + + + - .. row 1 + + - Identifier + + - Details + + - .. row 2 + + - ``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. + + - .. row 3 + + - ``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 + 0x00 and 0xff values). Cb and Cr are mapped from [-0.5…0.5] to + [0…255] (with possible clipping to [1…254] to avoid the 0x00 and + 0xff values). + + - .. row 4 + + - ``V4L2_QUANTIZATION_LIM_RANGE`` + + - Use the limited range quantization encoding. I.e. the range [0…1] + is mapped to [16…235]. Cb and Cr are mapped from [-0.5…0.5] to + [16…240]. |