Documentation/linux_tv/media/v4l/pixfmt-007.rst - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 .. -*- coding: utf-8; mode: rst -*-

 ********************************
 Detailed Colorspace Descriptions
 ********************************


 .. _col-smpte-170m:

 Colorspace SMPTE 170M (V4L2_COLORSPACE_SMPTE170M)
 =================================================

 The :ref:`smpte170m` standard defines the colorspace used by NTSC and
 PAL and by SDTV in general. The default transfer function is
 ``V4L2_XFER_FUNC_709``. The default Y'CbCr encoding is
 ``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited
 range. The chromaticities of the primary colors and the white reference
 are:


 .. flat-table:: SMPTE 170M Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.630

        -  0.340

     -  .. row 3

        -  Green

        -  0.310

        -  0.595

     -  .. row 4

        -  Blue

        -  0.155

        -  0.070

     -  .. row 5

        -  White Reference (D65)

        -  0.3127

        -  0.3290


 The red, green and blue chromaticities are also often referred to as the
 SMPTE C set, so this colorspace is sometimes called SMPTE C as well.

 The transfer function defined for SMPTE 170M is the same as the one
 defined in Rec. 709.

     L' = -1.099(-L) :sup:`0.45` + 0.099 for L ≤ -0.018

     L' = 4.5L for -0.018 < L < 0.018

     L' = 1.099L :sup:`0.45` - 0.099 for L ≥ 0.018

 Inverse Transfer function:

     L = -((L' - 0.099) / -1.099) :sup:`1/0.45` for L' ≤ -0.081

     L = L' / 4.5 for -0.081 < L' < 0.081

     L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_601`` encoding:

     Y' = 0.299R' + 0.587G' + 0.114B'

     Cb = -0.169R' - 0.331G' + 0.5B'

     Cr = 0.5R' - 0.419G' - 0.081B'

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5]. This conversion to Y'CbCr is identical to the one defined in
 the :ref:`itu601` standard and this colorspace is sometimes called
 BT.601 as well, even though BT.601 does not mention any color primaries.

 The default quantization is limited range, but full range is possible
 although rarely seen.


 .. _col-rec709:

 Colorspace Rec. 709 (V4L2_COLORSPACE_REC709)
 ============================================

 The :ref:`itu709` standard defines the colorspace used by HDTV in
 general. The default transfer function is ``V4L2_XFER_FUNC_709``. The
 default Y'CbCr encoding is ``V4L2_YCBCR_ENC_709``. The default Y'CbCr
 quantization is limited range. The chromaticities of the primary colors
 and the white reference are:


 .. flat-table:: Rec. 709 Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.640

        -  0.330

     -  .. row 3

        -  Green

        -  0.300

        -  0.600

     -  .. row 4

        -  Blue

        -  0.150

        -  0.060

     -  .. row 5

        -  White Reference (D65)

        -  0.3127

        -  0.3290


 The full name of this standard is Rec. ITU-R BT.709-5.

 Transfer function. Normally L is in the range [0…1], but for the
 extended gamut xvYCC encoding values outside that range are allowed.

     L' = -1.099(-L) :sup:`0.45` + 0.099 for L ≤ -0.018

     L' = 4.5L for -0.018 < L < 0.018

     L' = 1.099L :sup:`0.45` - 0.099 for L ≥ 0.018

 Inverse Transfer function:

     L = -((L' - 0.099) / -1.099) :sup:`1/0.45` for L' ≤ -0.081

     L = L' / 4.5 for -0.081 < L' < 0.081

     L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_709`` encoding:

     Y' = 0.2126R' + 0.7152G' + 0.0722B'

     Cb = -0.1146R' - 0.3854G' + 0.5B'

     Cr = 0.5R' - 0.4542G' - 0.0458B'

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5].

 The default quantization is limited range, but full range is possible
 although rarely seen.

 The ``V4L2_YCBCR_ENC_709`` encoding described above is the default for
 this colorspace, but it can be overridden with ``V4L2_YCBCR_ENC_601``,
 in which case the BT.601 Y'CbCr encoding is used.

 Two additional extended gamut Y'CbCr encodings are also possible with
 this colorspace:

 The xvYCC 709 encoding (``V4L2_YCBCR_ENC_XV709``, :ref:`xvycc`) is
 similar to the Rec. 709 encoding, but it allows for R', G' and B' values
 that are outside the range [0…1]. The resulting Y', Cb and Cr values are
 scaled and offset:

     Y' = (219 / 256) * (0.2126R' + 0.7152G' + 0.0722B') + (16 / 256)

     Cb = (224 / 256) * (-0.1146R' - 0.3854G' + 0.5B')

     Cr = (224 / 256) * (0.5R' - 0.4542G' - 0.0458B')

 The xvYCC 601 encoding (``V4L2_YCBCR_ENC_XV601``, :ref:`xvycc`) is
 similar to the BT.601 encoding, but it allows for R', G' and B' values
 that are outside the range [0…1]. The resulting Y', Cb and Cr values are
 scaled and offset:

     Y' = (219 / 256) * (0.299R' + 0.587G' + 0.114B') + (16 / 256)

     Cb = (224 / 256) * (-0.169R' - 0.331G' + 0.5B')

     Cr = (224 / 256) * (0.5R' - 0.419G' - 0.081B')

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5]. The non-standard xvYCC 709 or xvYCC 601 encodings can be
 used by selecting ``V4L2_YCBCR_ENC_XV709`` or ``V4L2_YCBCR_ENC_XV601``.
 The xvYCC encodings always use full range quantization.


 .. _col-srgb:

 Colorspace sRGB (V4L2_COLORSPACE_SRGB)
 ======================================

 The :ref:`srgb` standard defines the colorspace used by most webcams
 and computer graphics. The default transfer function is
 ``V4L2_XFER_FUNC_SRGB``. The default Y'CbCr encoding is
 ``V4L2_YCBCR_ENC_SYCC``. The default Y'CbCr quantization is full range.
 The chromaticities of the primary colors and the white reference are:


 .. flat-table:: sRGB Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.640

        -  0.330

     -  .. row 3

        -  Green

        -  0.300

        -  0.600

     -  .. row 4

        -  Blue

        -  0.150

        -  0.060

     -  .. row 5

        -  White Reference (D65)

        -  0.3127

        -  0.3290


 These chromaticities are identical to the Rec. 709 colorspace.

 Transfer function. Note that negative values for L are only used by the
 Y'CbCr conversion.

     L' = -1.055(-L) :sup:`1/2.4` + 0.055 for L < -0.0031308

     L' = 12.92L for -0.0031308 ≤ L ≤ 0.0031308

     L' = 1.055L :sup:`1/2.4` - 0.055 for 0.0031308 < L ≤ 1

 Inverse Transfer function:

     L = -((-L' + 0.055) / 1.055) :sup:`2.4` for L' < -0.04045

     L = L' / 12.92 for -0.04045 ≤ L' ≤ 0.04045

     L = ((L' + 0.055) / 1.055) :sup:`2.4` for L' > 0.04045

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_SYCC`` encoding as defined by
 :ref:`sycc`:

     Y' = 0.2990R' + 0.5870G' + 0.1140B'

     Cb = -0.1687R' - 0.3313G' + 0.5B'

     Cr = 0.5R' - 0.4187G' - 0.0813B'

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5]. The ``V4L2_YCBCR_ENC_SYCC`` quantization is always full
 range. Although this Y'CbCr encoding looks very similar to the
 ``V4L2_YCBCR_ENC_XV601`` encoding, it is not. The
 ``V4L2_YCBCR_ENC_XV601`` scales and offsets the Y'CbCr values before
 quantization, but this encoding does not do that.


 .. _col-adobergb:

 Colorspace Adobe RGB (V4L2_COLORSPACE_ADOBERGB)
 ===============================================

 The :ref:`adobergb` standard defines the colorspace used by computer
 graphics that use the AdobeRGB colorspace. This is also known as the
 :ref:`oprgb` standard. The default transfer function is
 ``V4L2_XFER_FUNC_ADOBERGB``. The default Y'CbCr encoding is
 ``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited
 range. The chromaticities of the primary colors and the white reference
 are:


 .. flat-table:: Adobe RGB Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.6400

        -  0.3300

     -  .. row 3

        -  Green

        -  0.2100

        -  0.7100

     -  .. row 4

        -  Blue

        -  0.1500

        -  0.0600

     -  .. row 5

        -  White Reference (D65)

        -  0.3127

        -  0.3290


 Transfer function:

     L' = L :sup:`1/2.19921875`

 Inverse Transfer function:

     L = L' :sup:`2.19921875`

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_601`` encoding:

     Y' = 0.299R' + 0.587G' + 0.114B'

     Cb = -0.169R' - 0.331G' + 0.5B'

     Cr = 0.5R' - 0.419G' - 0.081B'

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5]. This transform is identical to one defined in SMPTE
 170M/BT.601. The Y'CbCr quantization is limited range.


 .. _col-bt2020:

 Colorspace BT.2020 (V4L2_COLORSPACE_BT2020)
 ===========================================

 The :ref:`itu2020` standard defines the colorspace used by Ultra-high
 definition television (UHDTV). The default transfer function is
 ``V4L2_XFER_FUNC_709``. The default Y'CbCr encoding is
 ``V4L2_YCBCR_ENC_BT2020``. The default R'G'B' quantization is limited
 range (!), and so is the default Y'CbCr quantization. The chromaticities
 of the primary colors and the white reference are:


 .. flat-table:: BT.2020 Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.708

        -  0.292

     -  .. row 3

        -  Green

        -  0.170

        -  0.797

     -  .. row 4

        -  Blue

        -  0.131

        -  0.046

     -  .. row 5

        -  White Reference (D65)

        -  0.3127

        -  0.3290


 Transfer function (same as Rec. 709):

     L' = 4.5L for 0 ≤ L < 0.018

     L' = 1.099L :sup:`0.45` - 0.099 for 0.018 ≤ L ≤ 1

 Inverse Transfer function:

     L = L' / 4.5 for L' < 0.081

     L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_BT2020`` encoding:

     Y' = 0.2627R' + 0.6780G' + 0.0593B'

     Cb = -0.1396R' - 0.3604G' + 0.5B'

     Cr = 0.5R' - 0.4598G' - 0.0402B'

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5]. The Y'CbCr quantization is limited range.

 There is also an alternate constant luminance R'G'B' to Yc'CbcCrc
 (``V4L2_YCBCR_ENC_BT2020_CONST_LUM``) encoding:

 Luma:

     Yc' = (0.2627R + 0.6780G + 0.0593B)'

 B' - Yc' ≤ 0:

     Cbc = (B' - Yc') / 1.9404

 B' - Yc' > 0:

     Cbc = (B' - Yc') / 1.5816

 R' - Yc' ≤ 0:

     Crc = (R' - Y') / 1.7184

 R' - Yc' > 0:

     Crc = (R' - Y') / 0.9936

 Yc' is clamped to the range [0…1] and Cbc and Crc are clamped to the
 range [-0.5…0.5]. The Yc'CbcCrc quantization is limited range.


 .. _col-dcip3:

 Colorspace DCI-P3 (V4L2_COLORSPACE_DCI_P3)
 ==========================================

 The :ref:`smpte431` standard defines the colorspace used by cinema
 projectors that use the DCI-P3 colorspace. The default transfer function
 is ``V4L2_XFER_FUNC_DCI_P3``. The default Y'CbCr encoding is
 ``V4L2_YCBCR_ENC_709``. Note that this colorspace does not specify a
 Y'CbCr encoding since it is not meant to be encoded to Y'CbCr. So this
 default Y'CbCr encoding was picked because it is the HDTV encoding. The
 default Y'CbCr quantization is limited range. The chromaticities of the
 primary colors and the white reference are:


 .. flat-table:: DCI-P3 Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.6800

        -  0.3200

     -  .. row 3

        -  Green

        -  0.2650

        -  0.6900

     -  .. row 4

        -  Blue

        -  0.1500

        -  0.0600

     -  .. row 5

        -  White Reference

        -  0.3140

        -  0.3510


 Transfer function:

     L' = L :sup:`1/2.6`

 Inverse Transfer function:

     L = L' :sup:`2.6`

 Y'CbCr encoding is not specified. V4L2 defaults to Rec. 709.


 .. _col-smpte-240m:

 Colorspace SMPTE 240M (V4L2_COLORSPACE_SMPTE240M)
 =================================================

 The :ref:`smpte240m` standard was an interim standard used during the
 early days of HDTV (1988-1998). It has been superseded by Rec. 709. The
 default transfer function is ``V4L2_XFER_FUNC_SMPTE240M``. The default
 Y'CbCr encoding is ``V4L2_YCBCR_ENC_SMPTE240M``. The default Y'CbCr
 quantization is limited range. The chromaticities of the primary colors
 and the white reference are:


 .. flat-table:: SMPTE 240M Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.630

        -  0.340

     -  .. row 3

        -  Green

        -  0.310

        -  0.595

     -  .. row 4

        -  Blue

        -  0.155

        -  0.070

     -  .. row 5

        -  White Reference (D65)

        -  0.3127

        -  0.3290


 These chromaticities are identical to the SMPTE 170M colorspace.

 Transfer function:

     L' = 4L for 0 ≤ L < 0.0228

     L' = 1.1115L :sup:`0.45` - 0.1115 for 0.0228 ≤ L ≤ 1

 Inverse Transfer function:

     L = L' / 4 for 0 ≤ L' < 0.0913

     L = ((L' + 0.1115) / 1.1115) :sup:`1/0.45` for L' ≥ 0.0913

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_SMPTE240M`` encoding:

     Y' = 0.2122R' + 0.7013G' + 0.0865B'

     Cb = -0.1161R' - 0.3839G' + 0.5B'

     Cr = 0.5R' - 0.4451G' - 0.0549B'

 Yc' is clamped to the range [0…1] and Cbc and Crc are clamped to the
 range [-0.5…0.5]. The Y'CbCr quantization is limited range.


 .. _col-sysm:

 Colorspace NTSC 1953 (V4L2_COLORSPACE_470_SYSTEM_M)
 ===================================================

 This standard defines the colorspace used by NTSC in 1953. In practice
 this colorspace is obsolete and SMPTE 170M should be used instead. The
 default transfer function is ``V4L2_XFER_FUNC_709``. The default Y'CbCr
 encoding is ``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is
 limited range. The chromaticities of the primary colors and the white
 reference are:


 .. flat-table:: NTSC 1953 Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.67

        -  0.33

     -  .. row 3

        -  Green

        -  0.21

        -  0.71

     -  .. row 4

        -  Blue

        -  0.14

        -  0.08

     -  .. row 5

        -  White Reference (C)

        -  0.310

        -  0.316


 Note that this colorspace uses Illuminant C instead of D65 as the white
 reference. To correctly convert an image in this colorspace to another
 that uses D65 you need to apply a chromatic adaptation algorithm such as
 the Bradford method.

 The transfer function was never properly defined for NTSC 1953. The Rec.
 709 transfer function is recommended in the literature:

     L' = 4.5L for 0 ≤ L < 0.018

     L' = 1.099L :sup:`0.45` - 0.099 for 0.018 ≤ L ≤ 1

 Inverse Transfer function:

     L = L' / 4.5 for L' < 0.081

     L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_601`` encoding:

     Y' = 0.299R' + 0.587G' + 0.114B'

     Cb = -0.169R' - 0.331G' + 0.5B'

     Cr = 0.5R' - 0.419G' - 0.081B'

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5]. The Y'CbCr quantization is limited range. This transform is
 identical to one defined in SMPTE 170M/BT.601.


 .. _col-sysbg:

 Colorspace EBU Tech. 3213 (V4L2_COLORSPACE_470_SYSTEM_BG)
 =========================================================

 The :ref:`tech3213` standard defines the colorspace used by PAL/SECAM
 in 1975. In practice this colorspace is obsolete and SMPTE 170M should
 be used instead. The default transfer function is
 ``V4L2_XFER_FUNC_709``. The default Y'CbCr encoding is
 ``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited
 range. The chromaticities of the primary colors and the white reference
 are:


 .. flat-table:: EBU Tech. 3213 Chromaticities
     :header-rows:  1
     :stub-columns: 0
     :widths:       1 1 2


     -  .. row 1

        -  Color

        -  x

        -  y

     -  .. row 2

        -  Red

        -  0.64

        -  0.33

     -  .. row 3

        -  Green

        -  0.29

        -  0.60

     -  .. row 4

        -  Blue

        -  0.15

        -  0.06

     -  .. row 5

        -  White Reference (D65)

        -  0.3127

        -  0.3290


 The transfer function was never properly defined for this colorspace.
 The Rec. 709 transfer function is recommended in the literature:

     L' = 4.5L for 0 ≤ L < 0.018

     L' = 1.099L :sup:`0.45` - 0.099 for 0.018 ≤ L ≤ 1

 Inverse Transfer function:

     L = L' / 4.5 for L' < 0.081

     L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

 The luminance (Y') and color difference (Cb and Cr) are obtained with
 the following ``V4L2_YCBCR_ENC_601`` encoding:

     Y' = 0.299R' + 0.587G' + 0.114B'

     Cb = -0.169R' - 0.331G' + 0.5B'

     Cr = 0.5R' - 0.419G' - 0.081B'

 Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
 [-0.5…0.5]. The Y'CbCr quantization is limited range. This transform is
 identical to one defined in SMPTE 170M/BT.601.


 .. _col-jpeg:

 Colorspace JPEG (V4L2_COLORSPACE_JPEG)
 ======================================

 This colorspace defines the colorspace used by most (Motion-)JPEG
 formats. The chromaticities of the primary colors and the white
 reference are identical to sRGB. The transfer function use is
 ``V4L2_XFER_FUNC_SRGB``. The Y'CbCr encoding is ``V4L2_YCBCR_ENC_601``
 with full range quantization where Y' is scaled to [0…255] and Cb/Cr are
 scaled to [-128…128] and then clipped to [-128…127].

 Note that the JPEG standard does not actually store colorspace
 information. So if something other than sRGB is used, then the driver
 will have to set that information explicitly. Effectively
 ``V4L2_COLORSPACE_JPEG`` can be considered to be an abbreviation for
 ``V4L2_COLORSPACE_SRGB``, ``V4L2_YCBCR_ENC_601`` and
 ``V4L2_QUANTIZATION_FULL_RANGE``.
	.. -- coding: utf-8; mode: rst --

	********************************
	Detailed Colorspace Descriptions
	********************************


	.. _col-smpte-170m:

	Colorspace SMPTE 170M (V4L2_COLORSPACE_SMPTE170M)
	=================================================

	The :ref:`smpte170m` standard defines the colorspace used by NTSC and
	PAL and by SDTV in general. The default transfer function is
	``V4L2_XFER_FUNC_709``. The default Y'CbCr encoding is
	``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited
	range. The chromaticities of the primary colors and the white reference
	are:



	.. flat-table:: SMPTE 170M Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.630

	- 0.340

	- .. row 3

	- Green

	- 0.310

	- 0.595

	- .. row 4

	- Blue

	- 0.155

	- 0.070

	- .. row 5

	- White Reference (D65)

	- 0.3127

	- 0.3290


	The red, green and blue chromaticities are also often referred to as the
	SMPTE C set, so this colorspace is sometimes called SMPTE C as well.

	The transfer function defined for SMPTE 170M is the same as the one
	defined in Rec. 709.

	L' = -1.099(-L) :sup:`0.45` + 0.099 for L ≤ -0.018

	L' = 4.5L for -0.018 < L < 0.018

	L' = 1.099L :sup:`0.45` - 0.099 for L ≥ 0.018

	Inverse Transfer function:

	L = -((L' - 0.099) / -1.099) :sup:`1/0.45` for L' ≤ -0.081

	L = L' / 4.5 for -0.081 < L' < 0.081

	L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_601`` encoding:

	Y' = 0.299R' + 0.587G' + 0.114B'

	Cb = -0.169R' - 0.331G' + 0.5B'

	Cr = 0.5R' - 0.419G' - 0.081B'

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5]. This conversion to Y'CbCr is identical to the one defined in
	the :ref:`itu601` standard and this colorspace is sometimes called
	BT.601 as well, even though BT.601 does not mention any color primaries.

	The default quantization is limited range, but full range is possible
	although rarely seen.


	.. _col-rec709:

	Colorspace Rec. 709 (V4L2_COLORSPACE_REC709)
	============================================

	The :ref:`itu709` standard defines the colorspace used by HDTV in
	general. The default transfer function is ``V4L2_XFER_FUNC_709``. The
	default Y'CbCr encoding is ``V4L2_YCBCR_ENC_709``. The default Y'CbCr
	quantization is limited range. The chromaticities of the primary colors
	and the white reference are:



	.. flat-table:: Rec. 709 Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.640

	- 0.330

	- .. row 3

	- Green

	- 0.300

	- 0.600

	- .. row 4

	- Blue

	- 0.150

	- 0.060

	- .. row 5

	- White Reference (D65)

	- 0.3127

	- 0.3290


	The full name of this standard is Rec. ITU-R BT.709-5.

	Transfer function. Normally L is in the range [0…1], but for the
	extended gamut xvYCC encoding values outside that range are allowed.

	L' = -1.099(-L) :sup:`0.45` + 0.099 for L ≤ -0.018

	L' = 4.5L for -0.018 < L < 0.018

	L' = 1.099L :sup:`0.45` - 0.099 for L ≥ 0.018

	Inverse Transfer function:

	L = -((L' - 0.099) / -1.099) :sup:`1/0.45` for L' ≤ -0.081

	L = L' / 4.5 for -0.081 < L' < 0.081

	L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_709`` encoding:

	Y' = 0.2126R' + 0.7152G' + 0.0722B'

	Cb = -0.1146R' - 0.3854G' + 0.5B'

	Cr = 0.5R' - 0.4542G' - 0.0458B'

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5].

	The default quantization is limited range, but full range is possible
	although rarely seen.

	The ``V4L2_YCBCR_ENC_709`` encoding described above is the default for
	this colorspace, but it can be overridden with ``V4L2_YCBCR_ENC_601``,
	in which case the BT.601 Y'CbCr encoding is used.

	Two additional extended gamut Y'CbCr encodings are also possible with
	this colorspace:

	The xvYCC 709 encoding (``V4L2_YCBCR_ENC_XV709``, :ref:`xvycc`) is
	similar to the Rec. 709 encoding, but it allows for R', G' and B' values
	that are outside the range [0…1]. The resulting Y', Cb and Cr values are
	scaled and offset:

	Y' = (219 / 256) * (0.2126R' + 0.7152G' + 0.0722B') + (16 / 256)

	Cb = (224 / 256) * (-0.1146R' - 0.3854G' + 0.5B')

	Cr = (224 / 256) * (0.5R' - 0.4542G' - 0.0458B')

	The xvYCC 601 encoding (``V4L2_YCBCR_ENC_XV601``, :ref:`xvycc`) is
	similar to the BT.601 encoding, but it allows for R', G' and B' values
	that are outside the range [0…1]. The resulting Y', Cb and Cr values are
	scaled and offset:

	Y' = (219 / 256) * (0.299R' + 0.587G' + 0.114B') + (16 / 256)

	Cb = (224 / 256) * (-0.169R' - 0.331G' + 0.5B')

	Cr = (224 / 256) * (0.5R' - 0.419G' - 0.081B')

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5]. The non-standard xvYCC 709 or xvYCC 601 encodings can be
	used by selecting ``V4L2_YCBCR_ENC_XV709`` or ``V4L2_YCBCR_ENC_XV601``.
	The xvYCC encodings always use full range quantization.


	.. _col-srgb:

	Colorspace sRGB (V4L2_COLORSPACE_SRGB)
	======================================

	The :ref:`srgb` standard defines the colorspace used by most webcams
	and computer graphics. The default transfer function is
	``V4L2_XFER_FUNC_SRGB``. The default Y'CbCr encoding is
	``V4L2_YCBCR_ENC_SYCC``. The default Y'CbCr quantization is full range.
	The chromaticities of the primary colors and the white reference are:



	.. flat-table:: sRGB Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.640

	- 0.330

	- .. row 3

	- Green

	- 0.300

	- 0.600

	- .. row 4

	- Blue

	- 0.150

	- 0.060

	- .. row 5

	- White Reference (D65)

	- 0.3127

	- 0.3290


	These chromaticities are identical to the Rec. 709 colorspace.

	Transfer function. Note that negative values for L are only used by the
	Y'CbCr conversion.

	L' = -1.055(-L) :sup:`1/2.4` + 0.055 for L < -0.0031308

	L' = 12.92L for -0.0031308 ≤ L ≤ 0.0031308

	L' = 1.055L :sup:`1/2.4` - 0.055 for 0.0031308 < L ≤ 1

	Inverse Transfer function:

	L = -((-L' + 0.055) / 1.055) :sup:`2.4` for L' < -0.04045

	L = L' / 12.92 for -0.04045 ≤ L' ≤ 0.04045

	L = ((L' + 0.055) / 1.055) :sup:`2.4` for L' > 0.04045

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_SYCC`` encoding as defined by
	:ref:`sycc`:

	Y' = 0.2990R' + 0.5870G' + 0.1140B'

	Cb = -0.1687R' - 0.3313G' + 0.5B'

	Cr = 0.5R' - 0.4187G' - 0.0813B'

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5]. The ``V4L2_YCBCR_ENC_SYCC`` quantization is always full
	range. Although this Y'CbCr encoding looks very similar to the
	``V4L2_YCBCR_ENC_XV601`` encoding, it is not. The
	``V4L2_YCBCR_ENC_XV601`` scales and offsets the Y'CbCr values before
	quantization, but this encoding does not do that.


	.. _col-adobergb:

	Colorspace Adobe RGB (V4L2_COLORSPACE_ADOBERGB)
	===============================================

	The :ref:`adobergb` standard defines the colorspace used by computer
	graphics that use the AdobeRGB colorspace. This is also known as the
	:ref:`oprgb` standard. The default transfer function is
	``V4L2_XFER_FUNC_ADOBERGB``. The default Y'CbCr encoding is
	``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited
	range. The chromaticities of the primary colors and the white reference
	are:



	.. flat-table:: Adobe RGB Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.6400

	- 0.3300

	- .. row 3

	- Green

	- 0.2100

	- 0.7100

	- .. row 4

	- Blue

	- 0.1500

	- 0.0600

	- .. row 5

	- White Reference (D65)

	- 0.3127

	- 0.3290



	Transfer function:

	L' = L :sup:`1/2.19921875`

	Inverse Transfer function:

	L = L' :sup:`2.19921875`

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_601`` encoding:

	Y' = 0.299R' + 0.587G' + 0.114B'

	Cb = -0.169R' - 0.331G' + 0.5B'

	Cr = 0.5R' - 0.419G' - 0.081B'

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5]. This transform is identical to one defined in SMPTE
	170M/BT.601. The Y'CbCr quantization is limited range.


	.. _col-bt2020:

	Colorspace BT.2020 (V4L2_COLORSPACE_BT2020)
	===========================================

	The :ref:`itu2020` standard defines the colorspace used by Ultra-high
	definition television (UHDTV). The default transfer function is
	``V4L2_XFER_FUNC_709``. The default Y'CbCr encoding is
	``V4L2_YCBCR_ENC_BT2020``. The default R'G'B' quantization is limited
	range (!), and so is the default Y'CbCr quantization. The chromaticities
	of the primary colors and the white reference are:



	.. flat-table:: BT.2020 Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.708

	- 0.292

	- .. row 3

	- Green

	- 0.170

	- 0.797

	- .. row 4

	- Blue

	- 0.131

	- 0.046

	- .. row 5

	- White Reference (D65)

	- 0.3127

	- 0.3290



	Transfer function (same as Rec. 709):

	L' = 4.5L for 0 ≤ L < 0.018

	L' = 1.099L :sup:`0.45` - 0.099 for 0.018 ≤ L ≤ 1

	Inverse Transfer function:

	L = L' / 4.5 for L' < 0.081

	L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_BT2020`` encoding:

	Y' = 0.2627R' + 0.6780G' + 0.0593B'

	Cb = -0.1396R' - 0.3604G' + 0.5B'

	Cr = 0.5R' - 0.4598G' - 0.0402B'

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5]. The Y'CbCr quantization is limited range.

	There is also an alternate constant luminance R'G'B' to Yc'CbcCrc
	(``V4L2_YCBCR_ENC_BT2020_CONST_LUM``) encoding:

	Luma:

	Yc' = (0.2627R + 0.6780G + 0.0593B)'

	B' - Yc' ≤ 0:

	Cbc = (B' - Yc') / 1.9404

	B' - Yc' > 0:

	Cbc = (B' - Yc') / 1.5816

	R' - Yc' ≤ 0:

	Crc = (R' - Y') / 1.7184

	R' - Yc' > 0:

	Crc = (R' - Y') / 0.9936

	Yc' is clamped to the range [0…1] and Cbc and Crc are clamped to the
	range [-0.5…0.5]. The Yc'CbcCrc quantization is limited range.


	.. _col-dcip3:

	Colorspace DCI-P3 (V4L2_COLORSPACE_DCI_P3)
	==========================================

	The :ref:`smpte431` standard defines the colorspace used by cinema
	projectors that use the DCI-P3 colorspace. The default transfer function
	is ``V4L2_XFER_FUNC_DCI_P3``. The default Y'CbCr encoding is
	``V4L2_YCBCR_ENC_709``. Note that this colorspace does not specify a
	Y'CbCr encoding since it is not meant to be encoded to Y'CbCr. So this
	default Y'CbCr encoding was picked because it is the HDTV encoding. The
	default Y'CbCr quantization is limited range. The chromaticities of the
	primary colors and the white reference are:



	.. flat-table:: DCI-P3 Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.6800

	- 0.3200

	- .. row 3

	- Green

	- 0.2650

	- 0.6900

	- .. row 4

	- Blue

	- 0.1500

	- 0.0600

	- .. row 5

	- White Reference

	- 0.3140

	- 0.3510



	Transfer function:

	L' = L :sup:`1/2.6`

	Inverse Transfer function:

	L = L' :sup:`2.6`

	Y'CbCr encoding is not specified. V4L2 defaults to Rec. 709.


	.. _col-smpte-240m:

	Colorspace SMPTE 240M (V4L2_COLORSPACE_SMPTE240M)
	=================================================

	The :ref:`smpte240m` standard was an interim standard used during the
	early days of HDTV (1988-1998). It has been superseded by Rec. 709. The
	default transfer function is ``V4L2_XFER_FUNC_SMPTE240M``. The default
	Y'CbCr encoding is ``V4L2_YCBCR_ENC_SMPTE240M``. The default Y'CbCr
	quantization is limited range. The chromaticities of the primary colors
	and the white reference are:



	.. flat-table:: SMPTE 240M Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.630

	- 0.340

	- .. row 3

	- Green

	- 0.310

	- 0.595

	- .. row 4

	- Blue

	- 0.155

	- 0.070

	- .. row 5

	- White Reference (D65)

	- 0.3127

	- 0.3290


	These chromaticities are identical to the SMPTE 170M colorspace.

	Transfer function:

	L' = 4L for 0 ≤ L < 0.0228

	L' = 1.1115L :sup:`0.45` - 0.1115 for 0.0228 ≤ L ≤ 1

	Inverse Transfer function:

	L = L' / 4 for 0 ≤ L' < 0.0913

	L = ((L' + 0.1115) / 1.1115) :sup:`1/0.45` for L' ≥ 0.0913

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_SMPTE240M`` encoding:

	Y' = 0.2122R' + 0.7013G' + 0.0865B'

	Cb = -0.1161R' - 0.3839G' + 0.5B'

	Cr = 0.5R' - 0.4451G' - 0.0549B'

	Yc' is clamped to the range [0…1] and Cbc and Crc are clamped to the
	range [-0.5…0.5]. The Y'CbCr quantization is limited range.


	.. _col-sysm:

	Colorspace NTSC 1953 (V4L2_COLORSPACE_470_SYSTEM_M)
	===================================================

	This standard defines the colorspace used by NTSC in 1953. In practice
	this colorspace is obsolete and SMPTE 170M should be used instead. The
	default transfer function is ``V4L2_XFER_FUNC_709``. The default Y'CbCr
	encoding is ``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is
	limited range. The chromaticities of the primary colors and the white
	reference are:



	.. flat-table:: NTSC 1953 Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.67

	- 0.33

	- .. row 3

	- Green

	- 0.21

	- 0.71

	- .. row 4

	- Blue

	- 0.14

	- 0.08

	- .. row 5

	- White Reference (C)

	- 0.310

	- 0.316


	Note that this colorspace uses Illuminant C instead of D65 as the white
	reference. To correctly convert an image in this colorspace to another
	that uses D65 you need to apply a chromatic adaptation algorithm such as
	the Bradford method.

	The transfer function was never properly defined for NTSC 1953. The Rec.
	709 transfer function is recommended in the literature:

	L' = 4.5L for 0 ≤ L < 0.018

	L' = 1.099L :sup:`0.45` - 0.099 for 0.018 ≤ L ≤ 1

	Inverse Transfer function:

	L = L' / 4.5 for L' < 0.081

	L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_601`` encoding:

	Y' = 0.299R' + 0.587G' + 0.114B'

	Cb = -0.169R' - 0.331G' + 0.5B'

	Cr = 0.5R' - 0.419G' - 0.081B'

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5]. The Y'CbCr quantization is limited range. This transform is
	identical to one defined in SMPTE 170M/BT.601.


	.. _col-sysbg:

	Colorspace EBU Tech. 3213 (V4L2_COLORSPACE_470_SYSTEM_BG)
	=========================================================

	The :ref:`tech3213` standard defines the colorspace used by PAL/SECAM
	in 1975. In practice this colorspace is obsolete and SMPTE 170M should
	be used instead. The default transfer function is
	``V4L2_XFER_FUNC_709``. The default Y'CbCr encoding is
	``V4L2_YCBCR_ENC_601``. The default Y'CbCr quantization is limited
	range. The chromaticities of the primary colors and the white reference
	are:



	.. flat-table:: EBU Tech. 3213 Chromaticities
	:header-rows: 1
	:stub-columns: 0
	:widths: 1 1 2


	- .. row 1

	- Color

	- x

	- y

	- .. row 2

	- Red

	- 0.64

	- 0.33

	- .. row 3

	- Green

	- 0.29

	- 0.60

	- .. row 4

	- Blue

	- 0.15

	- 0.06

	- .. row 5

	- White Reference (D65)

	- 0.3127

	- 0.3290



	The transfer function was never properly defined for this colorspace.
	The Rec. 709 transfer function is recommended in the literature:

	L' = 4.5L for 0 ≤ L < 0.018

	L' = 1.099L :sup:`0.45` - 0.099 for 0.018 ≤ L ≤ 1

	Inverse Transfer function:

	L = L' / 4.5 for L' < 0.081

	L = ((L' + 0.099) / 1.099) :sup:`1/0.45` for L' ≥ 0.081

	The luminance (Y') and color difference (Cb and Cr) are obtained with
	the following ``V4L2_YCBCR_ENC_601`` encoding:

	Y' = 0.299R' + 0.587G' + 0.114B'

	Cb = -0.169R' - 0.331G' + 0.5B'

	Cr = 0.5R' - 0.419G' - 0.081B'

	Y' is clamped to the range [0…1] and Cb and Cr are clamped to the range
	[-0.5…0.5]. The Y'CbCr quantization is limited range. This transform is
	identical to one defined in SMPTE 170M/BT.601.


	.. _col-jpeg:

	Colorspace JPEG (V4L2_COLORSPACE_JPEG)
	======================================

	This colorspace defines the colorspace used by most (Motion-)JPEG
	formats. The chromaticities of the primary colors and the white
	reference are identical to sRGB. The transfer function use is
	``V4L2_XFER_FUNC_SRGB``. The Y'CbCr encoding is ``V4L2_YCBCR_ENC_601``
	with full range quantization where Y' is scaled to [0…255] and Cb/Cr are
	scaled to [-128…128] and then clipped to [-128…127].

	Note that the JPEG standard does not actually store colorspace
	information. So if something other than sRGB is used, then the driver
	will have to set that information explicitly. Effectively
	``V4L2_COLORSPACE_JPEG`` can be considered to be an abbreviation for
	``V4L2_COLORSPACE_SRGB``, ``V4L2_YCBCR_ENC_601`` and
	``V4L2_QUANTIZATION_FULL_RANGE``.