From 5dcd7c66bca7f9863f497345c114dc36ea3f3084 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 27 Jul 2017 04:58:52 -0400 Subject: media: media/doc: rename and reorder pixfmt files After the DocBook conversion a number of pixfmt description files just had a number in the filename (pix-fmt-004, 006, etc) which was not very descriptive. Rename them. Note that pixfmt-008.rst was folded into colorspaces-details.rst, so that file is deleted. It's easier to maintain that way. Also moved the colorspace sections to the end of the chapter. The old order was weird: the "Standard Image Formats" section (an intro into pixel formats) was followed by the colorspace sections instead of the pixel format descriptions. Moving it to the end resolved that issue. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/media/uapi/v4l/colorspaces-defs.rst | 174 +++++ .../media/uapi/v4l/colorspaces-details.rst | 790 +++++++++++++++++++++ Documentation/media/uapi/v4l/pixfmt-002.rst | 138 ---- Documentation/media/uapi/v4l/pixfmt-003.rst | 99 --- Documentation/media/uapi/v4l/pixfmt-004.rst | 51 -- Documentation/media/uapi/v4l/pixfmt-006.rst | 174 ----- Documentation/media/uapi/v4l/pixfmt-007.rst | 760 -------------------- Documentation/media/uapi/v4l/pixfmt-008.rst | 32 - Documentation/media/uapi/v4l/pixfmt-013.rst | 92 --- Documentation/media/uapi/v4l/pixfmt-compressed.rst | 92 +++ Documentation/media/uapi/v4l/pixfmt-intro.rst | 51 ++ .../media/uapi/v4l/pixfmt-v4l2-mplane.rst | 99 +++ Documentation/media/uapi/v4l/pixfmt-v4l2.rst | 138 ++++ Documentation/media/uapi/v4l/pixfmt.rst | 15 +- 14 files changed, 1351 insertions(+), 1354 deletions(-) create mode 100644 Documentation/media/uapi/v4l/colorspaces-defs.rst create mode 100644 Documentation/media/uapi/v4l/colorspaces-details.rst delete mode 100644 Documentation/media/uapi/v4l/pixfmt-002.rst delete mode 100644 Documentation/media/uapi/v4l/pixfmt-003.rst delete mode 100644 Documentation/media/uapi/v4l/pixfmt-004.rst delete mode 100644 Documentation/media/uapi/v4l/pixfmt-006.rst delete mode 100644 Documentation/media/uapi/v4l/pixfmt-007.rst delete mode 100644 Documentation/media/uapi/v4l/pixfmt-008.rst delete mode 100644 Documentation/media/uapi/v4l/pixfmt-013.rst create mode 100644 Documentation/media/uapi/v4l/pixfmt-compressed.rst create mode 100644 Documentation/media/uapi/v4l/pixfmt-intro.rst create mode 100644 Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst create mode 100644 Documentation/media/uapi/v4l/pixfmt-v4l2.rst (limited to 'Documentation/media') diff --git a/Documentation/media/uapi/v4l/colorspaces-defs.rst b/Documentation/media/uapi/v4l/colorspaces-defs.rst new file mode 100644 index 000000000000..7ae7dcf73f63 --- /dev/null +++ b/Documentation/media/uapi/v4l/colorspaces-defs.rst @@ -0,0 +1,174 @@ +.. -*- coding: utf-8; mode: rst -*- + +**************************** +Defining Colorspaces in V4L2 +**************************** + +In V4L2 colorspaces are defined by four values. The first is the +colorspace identifier (enum :c:type:`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 +:c:type:`v4l2_xfer_func`) to specify non-standard +transfer functions. The third is the Y'CbCr encoding identifier (enum +:c:type:`v4l2_ycbcr_encoding`) to specify +non-standard Y'CbCr encodings and the fourth is the quantization +identifier (enum :c:type:`v4l2_quantization`) to +specify non-standard quantization methods. Most of the time only the +colorspace field of struct :c:type:`v4l2_pix_format` +or struct :c:type:`v4l2_pix_format_mplane` +needs to be filled in. + +.. _hsv-colorspace: + +On :ref:`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. + +.. tabularcolumns:: |p{6.0cm}|p{11.5cm}| + +.. c:type:: v4l2_colorspace + +.. flat-table:: V4L2 Colorspaces + :header-rows: 1 + :stub-columns: 0 + + * - Identifier + - Details + * - ``V4L2_COLORSPACE_DEFAULT`` + - The default colorspace. This can be used by applications to let + the driver fill in the colorspace. + * - ``V4L2_COLORSPACE_SMPTE170M`` + - See :ref:`col-smpte-170m`. + * - ``V4L2_COLORSPACE_REC709`` + - See :ref:`col-rec709`. + * - ``V4L2_COLORSPACE_SRGB`` + - See :ref:`col-srgb`. + * - ``V4L2_COLORSPACE_ADOBERGB`` + - See :ref:`col-adobergb`. + * - ``V4L2_COLORSPACE_BT2020`` + - See :ref:`col-bt2020`. + * - ``V4L2_COLORSPACE_DCI_P3`` + - See :ref:`col-dcip3`. + * - ``V4L2_COLORSPACE_SMPTE240M`` + - See :ref:`col-smpte-240m`. + * - ``V4L2_COLORSPACE_470_SYSTEM_M`` + - See :ref:`col-sysm`. + * - ``V4L2_COLORSPACE_470_SYSTEM_BG`` + - See :ref:`col-sysbg`. + * - ``V4L2_COLORSPACE_JPEG`` + - See :ref:`col-jpeg`. + * - ``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. + + + +.. c:type:: v4l2_xfer_func + +.. flat-table:: V4L2 Transfer Function + :header-rows: 1 + :stub-columns: 0 + + * - Identifier + - Details + * - ``V4L2_XFER_FUNC_DEFAULT`` + - Use the default transfer function as defined by the colorspace. + * - ``V4L2_XFER_FUNC_709`` + - Use the Rec. 709 transfer function. + * - ``V4L2_XFER_FUNC_SRGB`` + - Use the sRGB transfer function. + * - ``V4L2_XFER_FUNC_ADOBERGB`` + - Use the AdobeRGB transfer function. + * - ``V4L2_XFER_FUNC_SMPTE240M`` + - Use the SMPTE 240M transfer function. + * - ``V4L2_XFER_FUNC_NONE`` + - Do not use a transfer function (i.e. use linear RGB values). + * - ``V4L2_XFER_FUNC_DCI_P3`` + - Use the DCI-P3 transfer function. + * - ``V4L2_XFER_FUNC_SMPTE2084`` + - Use the SMPTE 2084 transfer function. + + + +.. c:type:: v4l2_ycbcr_encoding + +.. tabularcolumns:: |p{6.5cm}|p{11.0cm}| + +.. flat-table:: V4L2 Y'CbCr Encodings + :header-rows: 1 + :stub-columns: 0 + + * - Identifier + - Details + * - ``V4L2_YCBCR_ENC_DEFAULT`` + - Use the default Y'CbCr encoding as defined by the colorspace. + * - ``V4L2_YCBCR_ENC_601`` + - Use the BT.601 Y'CbCr encoding. + * - ``V4L2_YCBCR_ENC_709`` + - Use the Rec. 709 Y'CbCr encoding. + * - ``V4L2_YCBCR_ENC_XV601`` + - Use the extended gamut xvYCC BT.601 encoding. + * - ``V4L2_YCBCR_ENC_XV709`` + - Use the extended gamut xvYCC Rec. 709 encoding. + * - ``V4L2_YCBCR_ENC_BT2020`` + - Use the default non-constant luminance BT.2020 Y'CbCr encoding. + * - ``V4L2_YCBCR_ENC_BT2020_CONST_LUM`` + - Use the constant luminance BT.2020 Yc'CbcCrc encoding. + * - ``V4L2_YCBCR_ENC_SMPTE_240M`` + - Use the SMPTE 240M Y'CbCr encoding. + + + +.. 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}| + +.. flat-table:: V4L2 Quantization Methods + :header-rows: 1 + :stub-columns: 0 + + * - Identifier + - Details + * - ``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 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 + 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). + * - ``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]. diff --git a/Documentation/media/uapi/v4l/colorspaces-details.rst b/Documentation/media/uapi/v4l/colorspaces-details.rst new file mode 100644 index 000000000000..128b2acbe824 --- /dev/null +++ b/Documentation/media/uapi/v4l/colorspaces-details.rst @@ -0,0 +1,790 @@ +.. -*- 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: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: SMPTE 170M Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.630 + - 0.340 + * - Green + - 0.310 + - 0.595 + * - Blue + - 0.155 + - 0.070 + * - 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. + +.. math:: + + L' = -1.099(-L)^{0.45} + 0.099 \text{, for } L \le-0.018 + + L' = 4.5L \text{, for } -0.018 < L < 0.018 + + L' = 1.099L^{0.45} - 0.099 \text{, for } L \ge 0.018 + +Inverse Transfer function: + +.. math:: + + L = -\left( \frac{L' - 0.099}{-1.099} \right) ^{\frac{1}{0.45}} \text{, for } L' \le -0.081 + + L = \frac{L'}{4.5} \text{, for } -0.081 < L' < 0.081 + + L = \left(\frac{L' + 0.099}{1.099}\right)^{\frac{1}{0.45} } \text{, for } L' \ge 0.081 + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_601`` encoding: + +.. math:: + + 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]. 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: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: Rec. 709 Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.640 + - 0.330 + * - Green + - 0.300 + - 0.600 + * - Blue + - 0.150 + - 0.060 + * - 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. + +.. math:: + + L' = -1.099(-L)^{0.45} + 0.099 \text{, for } L \le -0.018 + + L' = 4.5L \text{, for } -0.018 < L < 0.018 + + L' = 1.099L^{0.45} - 0.099 \text{, for } L \ge 0.018 + +Inverse Transfer function: + +.. math:: + + L = -\left( \frac{L' - 0.099}{-1.099} \right)^\frac{1}{0.45} \text{, for } L' \le -0.081 + + L = \frac{L'}{4.5}\text{, for } -0.081 < L' < 0.081 + + L = \left(\frac{L' + 0.099}{1.099}\right)^{\frac{1}{0.45} } \text{, for } L' \ge 0.081 + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_709`` encoding: + +.. math:: + + 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 according to the limited range formula: + +.. math:: + + Y' = \frac{219}{256} * (0.2126R' + 0.7152G' + 0.0722B') + \frac{16}{256} + + Cb = \frac{224}{256} * (-0.1146R' - 0.3854G' + 0.5B') + + Cr = \frac{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 according to the limited range formula: + +.. math:: + + Y' = \frac{219}{256} * (0.2990R' + 0.5870G' + 0.1140B') + \frac{16}{256} + + Cb = \frac{224}{256} * (-0.1687R' - 0.3313G' + 0.5B') + + Cr = \frac{224}{256} * (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] and quantized without further scaling or offsets. +The non-standard xvYCC 709 or xvYCC 601 encodings can be +used by selecting ``V4L2_YCBCR_ENC_XV709`` or ``V4L2_YCBCR_ENC_XV601``. +As seen by the xvYCC formulas these encodings always use limited range quantization, +there is no full range variant. The whole point of these extended gamut encodings +is that values outside the limited range are still valid, although they +map to R', G' and B' values outside the [0…1] range and are therefore outside +the Rec. 709 colorspace gamut. + + +.. _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_601``. The default Y'CbCr quantization is limited range. + +Note that the :ref:`sycc` standard specifies full range quantization, +however all current capture hardware supported by the kernel convert +R'G'B' to limited range Y'CbCr. So choosing full range as the default +would break how applications interpret the quantization range. + +The chromaticities of the primary colors and the white reference are: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: sRGB Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.640 + - 0.330 + * - Green + - 0.300 + - 0.600 + * - Blue + - 0.150 + - 0.060 + * - 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. + +.. math:: + + L' = -1.055(-L)^{\frac{1}{2.4} } + 0.055\text{, for }L < -0.0031308 + + L' = 12.92L\text{, for }-0.0031308 \le L \le 0.0031308 + + L' = 1.055L ^{\frac{1}{2.4} } - 0.055\text{, for }0.0031308 < L \le 1 + +Inverse Transfer function: + +.. math:: + + L = -((-L' + 0.055) / 1.055) ^{2.4}\text{, for }L' < -0.04045 + + L = L' / 12.92\text{, for }-0.04045 \le L' \le 0.04045 + + L = ((L' + 0.055) / 1.055) ^{2.4}\text{, for }L' > 0.04045 + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_601`` encoding as defined by :ref:`sycc`: + +.. math:: + + 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]. This transform is identical to one defined in SMPTE +170M/BT.601. The Y'CbCr quantization is limited range. + + +.. _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. + +Note that the :ref:`oprgb` standard specifies full range quantization, +however all current capture hardware supported by the kernel convert +R'G'B' to limited range Y'CbCr. So choosing full range as the default +would break how applications interpret the quantization range. + +The chromaticities of the primary colors and the white reference are: + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: Adobe RGB Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.6400 + - 0.3300 + * - Green + - 0.2100 + - 0.7100 + * - Blue + - 0.1500 + - 0.0600 + * - White Reference (D65) + - 0.3127 + - 0.3290 + + + +Transfer function: + +.. math:: + + L' = L ^{\frac{1}{2.19921875}} + +Inverse Transfer function: + +.. math:: + + L = L'^{(2.19921875)} + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_601`` encoding: + +.. math:: + + 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]. 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: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: BT.2020 Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.708 + - 0.292 + * - Green + - 0.170 + - 0.797 + * - Blue + - 0.131 + - 0.046 + * - White Reference (D65) + - 0.3127 + - 0.3290 + + + +Transfer function (same as Rec. 709): + +.. math:: + + L' = 4.5L\text{, for }0 \le L < 0.018 + + L' = 1.099L ^{0.45} - 0.099\text{, for } 0.018 \le L \le 1 + +Inverse Transfer function: + +.. math:: + + L = L' / 4.5\text{, for } L' < 0.081 + + L = \left( \frac{L' + 0.099}{1.099}\right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.081 + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_BT2020`` encoding: + +.. math:: + + 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: + +.. math:: + :nowrap: + + \begin{align*} + Yc' = (0.2627R + 0.6780G + 0.0593B)'& \\ + B' - Yc' \le 0:& \\ + &Cbc = (B' - Yc') / 1.9404 \\ + B' - Yc' > 0: & \\ + &Cbc = (B' - Yc') / 1.5816 \\ + R' - Yc' \le 0:& \\ + &Crc = (R' - Y') / 1.7184 \\ + R' - Yc' > 0:& \\ + &Crc = (R' - Y') / 0.9936 + \end{align*} + +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``. The default Y'CbCr quantization is limited range. + +.. note:: + + Note that this colorspace standard 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 chromaticities of the primary colors and the white reference are: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: DCI-P3 Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.6800 + - 0.3200 + * - Green + - 0.2650 + - 0.6900 + * - Blue + - 0.1500 + - 0.0600 + * - White Reference + - 0.3140 + - 0.3510 + + + +Transfer function: + +.. math:: + + L' = L^{\frac{1}{2.6}} + +Inverse Transfer function: + +.. math:: + + L = L'^{(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: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: SMPTE 240M Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.630 + - 0.340 + * - Green + - 0.310 + - 0.595 + * - Blue + - 0.155 + - 0.070 + * - White Reference (D65) + - 0.3127 + - 0.3290 + + +These chromaticities are identical to the SMPTE 170M colorspace. + +Transfer function: + +.. math:: + + L' = 4L\text{, for } 0 \le L < 0.0228 + + L' = 1.1115L ^{0.45} - 0.1115\text{, for } 0.0228 \le L \le 1 + +Inverse Transfer function: + +.. math:: + + L = \frac{L'}{4}\text{, for } 0 \le L' < 0.0913 + + L = \left( \frac{L' + 0.1115}{1.1115}\right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.0913 + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_SMPTE240M`` encoding: + +.. math:: + + Y' = 0.2122R' + 0.7013G' + 0.0865B' + + Cb = -0.1161R' - 0.3839G' + 0.5B' + + Cr = 0.5R' - 0.4451G' - 0.0549B' + +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. + + +.. _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: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: NTSC 1953 Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.67 + - 0.33 + * - Green + - 0.21 + - 0.71 + * - Blue + - 0.14 + - 0.08 + * - White Reference (C) + - 0.310 + - 0.316 + + +.. note:: + + 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: + +.. math:: + + L' = 4.5L\text{, for } 0 \le L < 0.018 + + L' = 1.099L ^{0.45} - 0.099\text{, for } 0.018 \le L \le 1 + +Inverse Transfer function: + +.. math:: + + L = \frac{L'}{4.5} \text{, for } L' < 0.081 + + L = \left( \frac{L' + 0.099}{1.099}\right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.081 + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_601`` encoding: + +.. math:: + + 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 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: + + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. flat-table:: EBU Tech. 3213 Chromaticities + :header-rows: 1 + :stub-columns: 0 + :widths: 1 1 2 + + * - Color + - x + - y + * - Red + - 0.64 + - 0.33 + * - Green + - 0.29 + - 0.60 + * - Blue + - 0.15 + - 0.06 + * - 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: + +.. math:: + + L' = 4.5L\text{, for } 0 \le L < 0.018 + + L' = 1.099L ^{0.45} - 0.099\text{, for } 0.018 \le L \le 1 + +Inverse Transfer function: + +.. math:: + + L = \frac{L'}{4.5} \text{, for } L' < 0.081 + + L = \left(\frac{L' + 0.099}{1.099} \right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.081 + +The luminance (Y') and color difference (Cb and Cr) are obtained with +the following ``V4L2_YCBCR_ENC_601`` encoding: + +.. math:: + + 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 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:: + + 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``. + +*************************************** +Detailed Transfer Function Descriptions +*************************************** + +.. _xf-smpte-2084: + +Transfer Function SMPTE 2084 (V4L2_XFER_FUNC_SMPTE2084) +======================================================= + +The :ref:`smpte2084` standard defines the transfer function used by +High Dynamic Range content. + +Constants: + m1 = (2610 / 4096) / 4 + + m2 = (2523 / 4096) * 128 + + c1 = 3424 / 4096 + + c2 = (2413 / 4096) * 32 + + c3 = (2392 / 4096) * 32 + +Transfer function: + L' = ((c1 + c2 * L\ :sup:`m1`) / (1 + c3 * L\ :sup:`m1`))\ :sup:`m2` + +Inverse Transfer function: + L = (max(L':sup:`1/m2` - c1, 0) / (c2 - c3 * + L'\ :sup:`1/m2`))\ :sup:`1/m1` diff --git a/Documentation/media/uapi/v4l/pixfmt-002.rst b/Documentation/media/uapi/v4l/pixfmt-002.rst deleted file mode 100644 index 2ee164c25637..000000000000 --- a/Documentation/media/uapi/v4l/pixfmt-002.rst +++ /dev/null @@ -1,138 +0,0 @@ -.. -*- coding: utf-8; mode: rst -*- - -****************************** -Single-planar format structure -****************************** - -.. tabularcolumns:: |p{4.0cm}|p{2.5cm}|p{11.0cm}| - -.. c:type:: v4l2_pix_format - -.. cssclass:: longtable - -.. flat-table:: struct v4l2_pix_format - :header-rows: 0 - :stub-columns: 0 - :widths: 1 1 2 - - * - __u32 - - ``width`` - - Image width in pixels. - * - __u32 - - ``height`` - - Image height in pixels. If ``field`` is one of ``V4L2_FIELD_TOP``, - ``V4L2_FIELD_BOTTOM`` or ``V4L2_FIELD_ALTERNATE`` then height - refers to the number of lines in the field, otherwise it refers to - the number of lines in the frame (which is twice the field height - for interlaced formats). - * - :cspan:`2` Applications set these fields to request an image - size, drivers return the closest possible values. In case of - planar formats the ``width`` and ``height`` applies to the largest - plane. To avoid ambiguities drivers must return values rounded up - to a multiple of the scale factor of any smaller planes. For - example when the image format is YUV 4:2:0, ``width`` and - ``height`` must be multiples of two. - * - __u32 - - ``pixelformat`` - - The pixel format or type of compression, set by the application. - This is a little endian - :ref:`four character code `. V4L2 defines standard - RGB formats in :ref:`rgb-formats`, YUV formats in - :ref:`yuv-formats`, and reserved codes in - :ref:`reserved-formats` - * - enum :c:type::`v4l2_field` - - ``field`` - - Video images are typically interlaced. Applications can request to - capture or output only the top or bottom field, or both fields - interlaced or sequentially stored in one buffer or alternating in - separate buffers. Drivers return the actual field order selected. - For more details on fields see :ref:`field-order`. - * - __u32 - - ``bytesperline`` - - Distance in bytes between the leftmost pixels in two adjacent - lines. - * - :cspan:`2` - - Both applications and drivers can set this field to request - padding bytes at the end of each line. Drivers however may ignore - the value requested by the application, returning ``width`` times - bytes per pixel or a larger value required by the hardware. That - implies applications can just set this field to zero to get a - reasonable default. - - Video hardware may access padding bytes, therefore they must - reside in accessible memory. Consider cases where padding bytes - after the last line of an image cross a system page boundary. - Input devices may write padding bytes, the value is undefined. - Output devices ignore the contents of padding bytes. - - When the image format is planar the ``bytesperline`` value applies - to the first plane and is divided by the same factor as the - ``width`` field for the other planes. For example the Cb and Cr - planes of a YUV 4:2:0 image have half as many padding bytes - following each line as the Y plane. To avoid ambiguities drivers - must return a ``bytesperline`` value rounded up to a multiple of - the scale factor. - - For compressed formats the ``bytesperline`` value makes no sense. - Applications and drivers must set this to 0 in that case. - * - __u32 - - ``sizeimage`` - - Size in bytes of the buffer to hold a complete image, set by the - driver. Usually this is ``bytesperline`` times ``height``. When - the image consists of variable length compressed data this is the - maximum number of bytes required to hold an image. - * - enum :c:type:`v4l2_colorspace` - - ``colorspace`` - - This information supplements the ``pixelformat`` and must be set - by the driver for capture streams and by the application for - output streams, see :ref:`colorspaces`. - * - __u32 - - ``priv`` - - This field indicates whether the remaining fields of the - struct :c:type:`v4l2_pix_format`, also called the - extended fields, are valid. When set to - ``V4L2_PIX_FMT_PRIV_MAGIC``, it indicates that the extended fields - have been correctly initialized. When set to any other value it - indicates that the extended fields contain undefined values. - - Applications that wish to use the pixel format extended fields - must first ensure that the feature is supported by querying the - device for the :ref:`V4L2_CAP_EXT_PIX_FORMAT ` - capability. If the capability isn't set the pixel format extended - fields are not supported and using the extended fields will lead - to undefined results. - - To use the extended fields, applications must set the ``priv`` - field to ``V4L2_PIX_FMT_PRIV_MAGIC``, initialize all the extended - fields and zero the unused bytes of the - struct :c:type:`v4l2_format` ``raw_data`` field. - - When the ``priv`` field isn't set to ``V4L2_PIX_FMT_PRIV_MAGIC`` - drivers must act as if all the extended fields were set to zero. - On return drivers must set the ``priv`` field to - ``V4L2_PIX_FMT_PRIV_MAGIC`` and all the extended fields to - applicable values. - * - __u32 - - ``flags`` - - Flags set by the application or driver, see :ref:`format-flags`. - * - enum :c:type:`v4l2_ycbcr_encoding` - - ``ycbcr_enc`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. - * - enum :c:type:`v4l2_hsv_encoding` - - ``hsv_enc`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. - * - enum :c:type:`v4l2_quantization` - - ``quantization`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. - * - enum :c:type:`v4l2_xfer_func` - - ``xfer_func`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. diff --git a/Documentation/media/uapi/v4l/pixfmt-003.rst b/Documentation/media/uapi/v4l/pixfmt-003.rst deleted file mode 100644 index 337e8188caf1..000000000000 --- a/Documentation/media/uapi/v4l/pixfmt-003.rst +++ /dev/null @@ -1,99 +0,0 @@ -.. -*- coding: utf-8; mode: rst -*- - -****************************** -Multi-planar format structures -****************************** - -The struct :c:type:`v4l2_plane_pix_format` structures define size -and layout for each of the planes in a multi-planar format. The -struct :c:type:`v4l2_pix_format_mplane` structure contains -information common to all planes (such as image width and height) and an -array of struct :c:type:`v4l2_plane_pix_format` structures, -describing all planes of that format. - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. c:type:: v4l2_plane_pix_format - -.. flat-table:: struct v4l2_plane_pix_format - :header-rows: 0 - :stub-columns: 0 - :widths: 1 1 2 - - * - __u32 - - ``sizeimage`` - - Maximum size in bytes required for image data in this plane. - * - __u32 - - ``bytesperline`` - - Distance in bytes between the leftmost pixels in two adjacent - lines. See struct :c:type:`v4l2_pix_format`. - * - __u16 - - ``reserved[6]`` - - Reserved for future extensions. Should be zeroed by drivers and - applications. - - -.. tabularcolumns:: |p{4.4cm}|p{5.6cm}|p{7.5cm}| - -.. c:type:: v4l2_pix_format_mplane - -.. flat-table:: struct v4l2_pix_format_mplane - :header-rows: 0 - :stub-columns: 0 - :widths: 1 1 2 - - * - __u32 - - ``width`` - - Image width in pixels. See struct - :c:type:`v4l2_pix_format`. - * - __u32 - - ``height`` - - Image height in pixels. See struct - :c:type:`v4l2_pix_format`. - * - __u32 - - ``pixelformat`` - - The pixel format. Both single- and multi-planar four character - codes can be used. - * - enum :c:type:`v4l2_field` - - ``field`` - - See struct :c:type:`v4l2_pix_format`. - * - enum :c:type:`v4l2_colorspace` - - ``colorspace`` - - See struct :c:type:`v4l2_pix_format`. - * - struct :c:type:`v4l2_plane_pix_format` - - ``plane_fmt[VIDEO_MAX_PLANES]`` - - An array of structures describing format of each plane this pixel - format consists of. The number of valid entries in this array has - to be put in the ``num_planes`` field. - * - __u8 - - ``num_planes`` - - Number of planes (i.e. separate memory buffers) for this format - and the number of valid entries in the ``plane_fmt`` array. - * - __u8 - - ``flags`` - - Flags set by the application or driver, see :ref:`format-flags`. - * - enum :c:type:`v4l2_ycbcr_encoding` - - ``ycbcr_enc`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. - * - enum :c:type:`v4l2_hsv_encoding` - - ``hsv_enc`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. - * - enum :c:type:`v4l2_quantization` - - ``quantization`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. - * - enum :c:type:`v4l2_xfer_func` - - ``xfer_func`` - - This information supplements the ``colorspace`` and must be set by - the driver for capture streams and by the application for output - streams, see :ref:`colorspaces`. - * - __u8 - - ``reserved[7]`` - - Reserved for future extensions. Should be zeroed by drivers and - applications. diff --git a/Documentation/media/uapi/v4l/pixfmt-004.rst b/Documentation/media/uapi/v4l/pixfmt-004.rst deleted file mode 100644 index 4bc116aa8193..000000000000 --- a/Documentation/media/uapi/v4l/pixfmt-004.rst +++ /dev/null @@ -1,51 +0,0 @@ -.. -*- coding: utf-8; mode: rst -*- - -********************** -Standard Image Formats -********************** - -In order to exchange images between drivers and applications, it is -necessary to have standard image data formats which both sides will -interpret the same way. V4L2 includes several such formats, and this -section is intended to be an unambiguous specification of the standard -image data formats in V4L2. - -V4L2 drivers are not limited to these formats, however. Driver-specific -formats are possible. In that case the application may depend on a codec -to convert images to one of the standard formats when needed. But the -data can still be stored and retrieved in the proprietary format. For -example, a device may support a proprietary compressed format. -Applications can still capture and save the data in the compressed -format, saving much disk space, and later use a codec to convert the -images to the X Windows screen format when the video is to be displayed. - -Even so, ultimately, some standard formats are needed, so the V4L2 -specification would not be complete without well-defined standard -formats. - -The V4L2 standard formats are mainly uncompressed formats. The pixels -are always arranged in memory from left to right, and from top to -bottom. The first byte of data in the image buffer is always for the -leftmost pixel of the topmost row. Following that is the pixel -immediately to its right, and so on until the end of the top row of -pixels. Following the rightmost pixel of the row there may be zero or -more bytes of padding to guarantee that each row of pixel data has a -certain alignment. Following the pad bytes, if any, is data for the -leftmost pixel of the second row from the top, and so on. The last row -has just as many pad bytes after it as the other rows. - -In V4L2 each format has an identifier which looks like ``PIX_FMT_XXX``, -defined in the :ref:`videodev2.h ` header file. These -identifiers represent -:ref:`four character (FourCC) codes ` which are also -listed below, however they are not the same as those used in the Windows -world. - -For some formats, data is stored in separate, discontiguous memory -buffers. Those formats are identified by a separate set of FourCC codes -and are referred to as "multi-planar formats". For example, a -:ref:`YUV422 ` frame is normally stored in one -memory buffer, but it can also be placed in two or three separate -buffers, with Y component in one buffer and CbCr components in another -in the 2-planar version or with each component in its own buffer in the -3-planar case. Those sub-buffers are referred to as "*planes*". diff --git a/Documentation/media/uapi/v4l/pixfmt-006.rst b/Documentation/media/uapi/v4l/pixfmt-006.rst deleted file mode 100644 index 7ae7dcf73f63..000000000000 --- a/Documentation/media/uapi/v4l/pixfmt-006.rst +++ /dev/null @@ -1,174 +0,0 @@ -.. -*- coding: utf-8; mode: rst -*- - -**************************** -Defining Colorspaces in V4L2 -**************************** - -In V4L2 colorspaces are defined by four values. The first is the -colorspace identifier (enum :c:type:`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 -:c:type:`v4l2_xfer_func`) to specify non-standard -transfer functions. The third is the Y'CbCr encoding identifier (enum -:c:type:`v4l2_ycbcr_encoding`) to specify -non-standard Y'CbCr encodings and the fourth is the quantization -identifier (enum :c:type:`v4l2_quantization`) to -specify non-standard quantization methods. Most of the time only the -colorspace field of struct :c:type:`v4l2_pix_format` -or struct :c:type:`v4l2_pix_format_mplane` -needs to be filled in. - -.. _hsv-colorspace: - -On :ref:`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. - -.. tabularcolumns:: |p{6.0cm}|p{11.5cm}| - -.. c:type:: v4l2_colorspace - -.. flat-table:: V4L2 Colorspaces - :header-rows: 1 - :stub-columns: 0 - - * - Identifier - - Details - * - ``V4L2_COLORSPACE_DEFAULT`` - - The default colorspace. This can be used by applications to let - the driver fill in the colorspace. - * - ``V4L2_COLORSPACE_SMPTE170M`` - - See :ref:`col-smpte-170m`. - * - ``V4L2_COLORSPACE_REC709`` - - See :ref:`col-rec709`. - * - ``V4L2_COLORSPACE_SRGB`` - - See :ref:`col-srgb`. - * - ``V4L2_COLORSPACE_ADOBERGB`` - - See :ref:`col-adobergb`. - * - ``V4L2_COLORSPACE_BT2020`` - - See :ref:`col-bt2020`. - * - ``V4L2_COLORSPACE_DCI_P3`` - - See :ref:`col-dcip3`. - * - ``V4L2_COLORSPACE_SMPTE240M`` - - See :ref:`col-smpte-240m`. - * - ``V4L2_COLORSPACE_470_SYSTEM_M`` - - See :ref:`col-sysm`. - * - ``V4L2_COLORSPACE_470_SYSTEM_BG`` - - See :ref:`col-sysbg`. - * - ``V4L2_COLORSPACE_JPEG`` - - See :ref:`col-jpeg`. - * - ``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. - - - -.. c:type:: v4l2_xfer_func - -.. flat-table:: V4L2 Transfer Function - :header-rows: 1 - :stub-columns: 0 - - * - Identifier - - Details - * - ``V4L2_XFER_FUNC_DEFAULT`` - - Use the default transfer function as defined by the colorspace. - * - ``V4L2_XFER_FUNC_709`` - - Use the Rec. 709 transfer function. - * - ``V4L2_XFER_FUNC_SRGB`` - - Use the sRGB transfer function. - * - ``V4L2_XFER_FUNC_ADOBERGB`` - - Use the AdobeRGB transfer function. - * - ``V4L2_XFER_FUNC_SMPTE240M`` - - Use the SMPTE 240M transfer function. - * - ``V4L2_XFER_FUNC_NONE`` - - Do not use a transfer function (i.e. use linear RGB values). - * - ``V4L2_XFER_FUNC_DCI_P3`` - - Use the DCI-P3 transfer function. - * - ``V4L2_XFER_FUNC_SMPTE2084`` - - Use the SMPTE 2084 transfer function. - - - -.. c:type:: v4l2_ycbcr_encoding - -.. tabularcolumns:: |p{6.5cm}|p{11.0cm}| - -.. flat-table:: V4L2 Y'CbCr Encodings - :header-rows: 1 - :stub-columns: 0 - - * - Identifier - - Details - * - ``V4L2_YCBCR_ENC_DEFAULT`` - - Use the default Y'CbCr encoding as defined by the colorspace. - * - ``V4L2_YCBCR_ENC_601`` - - Use the BT.601 Y'CbCr encoding. - * - ``V4L2_YCBCR_ENC_709`` - - Use the Rec. 709 Y'CbCr encoding. - * - ``V4L2_YCBCR_ENC_XV601`` - - Use the extended gamut xvYCC BT.601 encoding. - * - ``V4L2_YCBCR_ENC_XV709`` - - Use the extended gamut xvYCC Rec. 709 encoding. - * - ``V4L2_YCBCR_ENC_BT2020`` - - Use the default non-constant luminance BT.2020 Y'CbCr encoding. - * - ``V4L2_YCBCR_ENC_BT2020_CONST_LUM`` - - Use the constant luminance BT.2020 Yc'CbcCrc encoding. - * - ``V4L2_YCBCR_ENC_SMPTE_240M`` - - Use the SMPTE 240M Y'CbCr encoding. - - - -.. 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}| - -.. flat-table:: V4L2 Quantization Methods - :header-rows: 1 - :stub-columns: 0 - - * - Identifier - - Details - * - ``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 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 - 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). - * - ``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]. diff --git a/Documentation/media/uapi/v4l/pixfmt-007.rst b/Documentation/media/uapi/v4l/pixfmt-007.rst deleted file mode 100644 index 0c30ee2577d3..000000000000 --- a/Documentation/media/uapi/v4l/pixfmt-007.rst +++ /dev/null @@ -1,760 +0,0 @@ -.. -*- 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: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: SMPTE 170M Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.630 - - 0.340 - * - Green - - 0.310 - - 0.595 - * - Blue - - 0.155 - - 0.070 - * - 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. - -.. math:: - - L' = -1.099(-L)^{0.45} + 0.099 \text{, for } L \le-0.018 - - L' = 4.5L \text{, for } -0.018 < L < 0.018 - - L' = 1.099L^{0.45} - 0.099 \text{, for } L \ge 0.018 - -Inverse Transfer function: - -.. math:: - - L = -\left( \frac{L' - 0.099}{-1.099} \right) ^{\frac{1}{0.45}} \text{, for } L' \le -0.081 - - L = \frac{L'}{4.5} \text{, for } -0.081 < L' < 0.081 - - L = \left(\frac{L' + 0.099}{1.099}\right)^{\frac{1}{0.45} } \text{, for } L' \ge 0.081 - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_601`` encoding: - -.. math:: - - 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]. 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: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: Rec. 709 Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.640 - - 0.330 - * - Green - - 0.300 - - 0.600 - * - Blue - - 0.150 - - 0.060 - * - 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. - -.. math:: - - L' = -1.099(-L)^{0.45} + 0.099 \text{, for } L \le -0.018 - - L' = 4.5L \text{, for } -0.018 < L < 0.018 - - L' = 1.099L^{0.45} - 0.099 \text{, for } L \ge 0.018 - -Inverse Transfer function: - -.. math:: - - L = -\left( \frac{L' - 0.099}{-1.099} \right)^\frac{1}{0.45} \text{, for } L' \le -0.081 - - L = \frac{L'}{4.5}\text{, for } -0.081 < L' < 0.081 - - L = \left(\frac{L' + 0.099}{1.099}\right)^{\frac{1}{0.45} } \text{, for } L' \ge 0.081 - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_709`` encoding: - -.. math:: - - 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 according to the limited range formula: - -.. math:: - - Y' = \frac{219}{256} * (0.2126R' + 0.7152G' + 0.0722B') + \frac{16}{256} - - Cb = \frac{224}{256} * (-0.1146R' - 0.3854G' + 0.5B') - - Cr = \frac{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 according to the limited range formula: - -.. math:: - - Y' = \frac{219}{256} * (0.2990R' + 0.5870G' + 0.1140B') + \frac{16}{256} - - Cb = \frac{224}{256} * (-0.1687R' - 0.3313G' + 0.5B') - - Cr = \frac{224}{256} * (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] and quantized without further scaling or offsets. -The non-standard xvYCC 709 or xvYCC 601 encodings can be -used by selecting ``V4L2_YCBCR_ENC_XV709`` or ``V4L2_YCBCR_ENC_XV601``. -As seen by the xvYCC formulas these encodings always use limited range quantization, -there is no full range variant. The whole point of these extended gamut encodings -is that values outside the limited range are still valid, although they -map to R', G' and B' values outside the [0…1] range and are therefore outside -the Rec. 709 colorspace gamut. - - -.. _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_601``. The default Y'CbCr quantization is limited range. - -Note that the :ref:`sycc` standard specifies full range quantization, -however all current capture hardware supported by the kernel convert -R'G'B' to limited range Y'CbCr. So choosing full range as the default -would break how applications interpret the quantization range. - -The chromaticities of the primary colors and the white reference are: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: sRGB Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.640 - - 0.330 - * - Green - - 0.300 - - 0.600 - * - Blue - - 0.150 - - 0.060 - * - 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. - -.. math:: - - L' = -1.055(-L)^{\frac{1}{2.4} } + 0.055\text{, for }L < -0.0031308 - - L' = 12.92L\text{, for }-0.0031308 \le L \le 0.0031308 - - L' = 1.055L ^{\frac{1}{2.4} } - 0.055\text{, for }0.0031308 < L \le 1 - -Inverse Transfer function: - -.. math:: - - L = -((-L' + 0.055) / 1.055) ^{2.4}\text{, for }L' < -0.04045 - - L = L' / 12.92\text{, for }-0.04045 \le L' \le 0.04045 - - L = ((L' + 0.055) / 1.055) ^{2.4}\text{, for }L' > 0.04045 - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_601`` encoding as defined by :ref:`sycc`: - -.. math:: - - 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]. This transform is identical to one defined in SMPTE -170M/BT.601. The Y'CbCr quantization is limited range. - - -.. _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. - -Note that the :ref:`oprgb` standard specifies full range quantization, -however all current capture hardware supported by the kernel convert -R'G'B' to limited range Y'CbCr. So choosing full range as the default -would break how applications interpret the quantization range. - -The chromaticities of the primary colors and the white reference are: - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: Adobe RGB Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.6400 - - 0.3300 - * - Green - - 0.2100 - - 0.7100 - * - Blue - - 0.1500 - - 0.0600 - * - White Reference (D65) - - 0.3127 - - 0.3290 - - - -Transfer function: - -.. math:: - - L' = L ^{\frac{1}{2.19921875}} - -Inverse Transfer function: - -.. math:: - - L = L'^{(2.19921875)} - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_601`` encoding: - -.. math:: - - 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]. 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: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: BT.2020 Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.708 - - 0.292 - * - Green - - 0.170 - - 0.797 - * - Blue - - 0.131 - - 0.046 - * - White Reference (D65) - - 0.3127 - - 0.3290 - - - -Transfer function (same as Rec. 709): - -.. math:: - - L' = 4.5L\text{, for }0 \le L < 0.018 - - L' = 1.099L ^{0.45} - 0.099\text{, for } 0.018 \le L \le 1 - -Inverse Transfer function: - -.. math:: - - L = L' / 4.5\text{, for } L' < 0.081 - - L = \left( \frac{L' + 0.099}{1.099}\right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.081 - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_BT2020`` encoding: - -.. math:: - - 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: - -.. math:: - :nowrap: - - \begin{align*} - Yc' = (0.2627R + 0.6780G + 0.0593B)'& \\ - B' - Yc' \le 0:& \\ - &Cbc = (B' - Yc') / 1.9404 \\ - B' - Yc' > 0: & \\ - &Cbc = (B' - Yc') / 1.5816 \\ - R' - Yc' \le 0:& \\ - &Crc = (R' - Y') / 1.7184 \\ - R' - Yc' > 0:& \\ - &Crc = (R' - Y') / 0.9936 - \end{align*} - -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``. The default Y'CbCr quantization is limited range. - -.. note:: - - Note that this colorspace standard 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 chromaticities of the primary colors and the white reference are: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: DCI-P3 Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.6800 - - 0.3200 - * - Green - - 0.2650 - - 0.6900 - * - Blue - - 0.1500 - - 0.0600 - * - White Reference - - 0.3140 - - 0.3510 - - - -Transfer function: - -.. math:: - - L' = L^{\frac{1}{2.6}} - -Inverse Transfer function: - -.. math:: - - L = L'^{(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: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: SMPTE 240M Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.630 - - 0.340 - * - Green - - 0.310 - - 0.595 - * - Blue - - 0.155 - - 0.070 - * - White Reference (D65) - - 0.3127 - - 0.3290 - - -These chromaticities are identical to the SMPTE 170M colorspace. - -Transfer function: - -.. math:: - - L' = 4L\text{, for } 0 \le L < 0.0228 - - L' = 1.1115L ^{0.45} - 0.1115\text{, for } 0.0228 \le L \le 1 - -Inverse Transfer function: - -.. math:: - - L = \frac{L'}{4}\text{, for } 0 \le L' < 0.0913 - - L = \left( \frac{L' + 0.1115}{1.1115}\right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.0913 - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_SMPTE240M`` encoding: - -.. math:: - - Y' = 0.2122R' + 0.7013G' + 0.0865B' - - Cb = -0.1161R' - 0.3839G' + 0.5B' - - Cr = 0.5R' - 0.4451G' - 0.0549B' - -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. - - -.. _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: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: NTSC 1953 Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.67 - - 0.33 - * - Green - - 0.21 - - 0.71 - * - Blue - - 0.14 - - 0.08 - * - White Reference (C) - - 0.310 - - 0.316 - - -.. note:: - - 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: - -.. math:: - - L' = 4.5L\text{, for } 0 \le L < 0.018 - - L' = 1.099L ^{0.45} - 0.099\text{, for } 0.018 \le L \le 1 - -Inverse Transfer function: - -.. math:: - - L = \frac{L'}{4.5} \text{, for } L' < 0.081 - - L = \left( \frac{L' + 0.099}{1.099}\right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.081 - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_601`` encoding: - -.. math:: - - 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 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: - - - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: EBU Tech. 3213 Chromaticities - :header-rows: 1 - :stub-columns: 0 - :widths: 1 1 2 - - * - Color - - x - - y - * - Red - - 0.64 - - 0.33 - * - Green - - 0.29 - - 0.60 - * - Blue - - 0.15 - - 0.06 - * - 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: - -.. math:: - - L' = 4.5L\text{, for } 0 \le L < 0.018 - - L' = 1.099L ^{0.45} - 0.099\text{, for } 0.018 \le L \le 1 - -Inverse Transfer function: - -.. math:: - - L = \frac{L'}{4.5} \text{, for } L' < 0.081 - - L = \left(\frac{L' + 0.099}{1.099} \right) ^{\frac{1}{0.45} }\text{, for } L' \ge 0.081 - -The luminance (Y') and color difference (Cb and Cr) are obtained with -the following ``V4L2_YCBCR_ENC_601`` encoding: - -.. math:: - - 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 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:: - - 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``. diff --git a/Documentation/media/uapi/v4l/pixfmt-008.rst b/Documentation/media/uapi/v4l/pixfmt-008.rst deleted file mode 100644 index 4bec79784bdd..000000000000 --- a/Documentation/media/uapi/v4l/pixfmt-008.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. -*- coding: utf-8; mode: rst -*- - -*************************************** -Detailed Transfer Function Descriptions -*************************************** - - -.. _xf-smpte-2084: - -Transfer Function SMPTE 2084 (V4L2_XFER_FUNC_SMPTE2084) -======================================================= - -The :ref:`smpte2084` standard defines the transfer function used by -High Dynamic Range content. - -Constants: - m1 = (2610 / 4096) / 4 - - m2 = (2523 / 4096) * 128 - - c1 = 3424 / 4096 - - c2 = (2413 / 4096) * 32 - - c3 = (2392 / 4096) * 32 - -Transfer function: - L' = ((c1 + c2 * L\ :sup:`m1`) / (1 + c3 * L\ :sup:`m1`))\ :sup:`m2` - -Inverse Transfer function: - L = (max(L':sup:`1/m2` - c1, 0) / (c2 - c3 * - L'\ :sup:`1/m2`))\ :sup:`1/m1` diff --git a/Documentation/media/uapi/v4l/pixfmt-013.rst b/Documentation/media/uapi/v4l/pixfmt-013.rst deleted file mode 100644 index 728d7ede10fa..000000000000 --- a/Documentation/media/uapi/v4l/pixfmt-013.rst +++ /dev/null @@ -1,92 +0,0 @@ -.. -*- coding: utf-8; mode: rst -*- - -****************** -Compressed Formats -****************** - - -.. _compressed-formats: - -.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| - -.. flat-table:: Compressed Image Formats - :header-rows: 1 - :stub-columns: 0 - :widths: 3 1 4 - - * - Identifier - - Code - - Details - * .. _V4L2-PIX-FMT-JPEG: - - - ``V4L2_PIX_FMT_JPEG`` - - 'JPEG' - - TBD. See also :ref:`VIDIOC_G_JPEGCOMP `, - :ref:`VIDIOC_S_JPEGCOMP `. - * .. _V4L2-PIX-FMT-MPEG: - - - ``V4L2_PIX_FMT_MPEG`` - - 'MPEG' - - MPEG multiplexed stream. The actual format is determined by - extended control ``V4L2_CID_MPEG_STREAM_TYPE``, see - :ref:`mpeg-control-id`. - * .. _V4L2-PIX-FMT-H264: - - - ``V4L2_PIX_FMT_H264`` - - 'H264' - - H264 video elementary stream with start codes. - * .. _V4L2-PIX-FMT-H264-NO-SC: - - - ``V4L2_PIX_FMT_H264_NO_SC`` - - 'AVC1' - - H264 video elementary stream without start codes. - * .. _V4L2-PIX-FMT-H264-MVC: - - - ``V4L2_PIX_FMT_H264_MVC`` - - 'M264' - - H264 MVC video elementary stream. - * .. _V4L2-PIX-FMT-H263: - - - ``V4L2_PIX_FMT_H263`` - - 'H263' - - H263 video elementary stream. - * .. _V4L2-PIX-FMT-MPEG1: - - - ``V4L2_PIX_FMT_MPEG1`` - - 'MPG1' - - MPEG1 video elementary stream. - * .. _V4L2-PIX-FMT-MPEG2: - - - ``V4L2_PIX_FMT_MPEG2`` - - 'MPG2' - - MPEG2 video elementary stream. - * .. _V4L2-PIX-FMT-MPEG4: - - - ``V4L2_PIX_FMT_MPEG4`` - - 'MPG4' - - MPEG4 video elementary stream. - * .. _V4L2-PIX-FMT-XVID: - - - ``V4L2_PIX_FMT_XVID`` - - 'XVID' - - Xvid video elementary stream. - * .. _V4L2-PIX-FMT-VC1-ANNEX-G: - - - ``V4L2_PIX_FMT_VC1_ANNEX_G`` - - 'VC1G' - - VC1, SMPTE 421M Annex G compliant stream. - * .. _V4L2-PIX-FMT-VC1-ANNEX-L: - - - ``V4L2_PIX_FMT_VC1_ANNEX_L`` - - 'VC1L' - - VC1, SMPTE 421M Annex L compliant stream. - * .. _V4L2-PIX-FMT-VP8: - - - ``V4L2_PIX_FMT_VP8`` - - 'VP80' - - VP8 video elementary stream. - * .. _V4L2-PIX-FMT-VP9: - - - ``V4L2_PIX_FMT_VP9`` - - 'VP90' - - VP9 video elementary stream. diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst new file mode 100644 index 000000000000..728d7ede10fa --- /dev/null +++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst @@ -0,0 +1,92 @@ +.. -*- coding: utf-8; mode: rst -*- + +****************** +Compressed Formats +****************** + + +.. _compressed-formats: + +.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| + +.. flat-table:: Compressed Image Formats + :header-rows: 1 + :stub-columns: 0 + :widths: 3 1 4 + + * - Identifier + - Code + - Details + * .. _V4L2-PIX-FMT-JPEG: + + - ``V4L2_PIX_FMT_JPEG`` + - 'JPEG' + - TBD. See also :ref:`VIDIOC_G_JPEGCOMP `, + :ref:`VIDIOC_S_JPEGCOMP `. + * .. _V4L2-PIX-FMT-MPEG: + + - ``V4L2_PIX_FMT_MPEG`` + - 'MPEG' + - MPEG multiplexed stream. The actual format is determined by + extended control ``V4L2_CID_MPEG_STREAM_TYPE``, see + :ref:`mpeg-control-id`. + * .. _V4L2-PIX-FMT-H264: + + - ``V4L2_PIX_FMT_H264`` + - 'H264' + - H264 video elementary stream with start codes. + * .. _V4L2-PIX-FMT-H264-NO-SC: + + - ``V4L2_PIX_FMT_H264_NO_SC`` + - 'AVC1' + - H264 video elementary stream without start codes. + * .. _V4L2-PIX-FMT-H264-MVC: + + - ``V4L2_PIX_FMT_H264_MVC`` + - 'M264' + - H264 MVC video elementary stream. + * .. _V4L2-PIX-FMT-H263: + + - ``V4L2_PIX_FMT_H263`` + - 'H263' + - H263 video elementary stream. + * .. _V4L2-PIX-FMT-MPEG1: + + - ``V4L2_PIX_FMT_MPEG1`` + - 'MPG1' + - MPEG1 video elementary stream. + * .. _V4L2-PIX-FMT-MPEG2: + + - ``V4L2_PIX_FMT_MPEG2`` + - 'MPG2' + - MPEG2 video elementary stream. + * .. _V4L2-PIX-FMT-MPEG4: + + - ``V4L2_PIX_FMT_MPEG4`` + - 'MPG4' + - MPEG4 video elementary stream. + * .. _V4L2-PIX-FMT-XVID: + + - ``V4L2_PIX_FMT_XVID`` + - 'XVID' + - Xvid video elementary stream. + * .. _V4L2-PIX-FMT-VC1-ANNEX-G: + + - ``V4L2_PIX_FMT_VC1_ANNEX_G`` + - 'VC1G' + - VC1, SMPTE 421M Annex G compliant stream. + * .. _V4L2-PIX-FMT-VC1-ANNEX-L: + + - ``V4L2_PIX_FMT_VC1_ANNEX_L`` + - 'VC1L' + - VC1, SMPTE 421M Annex L compliant stream. + * .. _V4L2-PIX-FMT-VP8: + + - ``V4L2_PIX_FMT_VP8`` + - 'VP80' + - VP8 video elementary stream. + * .. _V4L2-PIX-FMT-VP9: + + - ``V4L2_PIX_FMT_VP9`` + - 'VP90' + - VP9 video elementary stream. diff --git a/Documentation/media/uapi/v4l/pixfmt-intro.rst b/Documentation/media/uapi/v4l/pixfmt-intro.rst new file mode 100644 index 000000000000..4bc116aa8193 --- /dev/null +++ b/Documentation/media/uapi/v4l/pixfmt-intro.rst @@ -0,0 +1,51 @@ +.. -*- coding: utf-8; mode: rst -*- + +********************** +Standard Image Formats +********************** + +In order to exchange images between drivers and applications, it is +necessary to have standard image data formats which both sides will +interpret the same way. V4L2 includes several such formats, and this +section is intended to be an unambiguous specification of the standard +image data formats in V4L2. + +V4L2 drivers are not limited to these formats, however. Driver-specific +formats are possible. In that case the application may depend on a codec +to convert images to one of the standard formats when needed. But the +data can still be stored and retrieved in the proprietary format. For +example, a device may support a proprietary compressed format. +Applications can still capture and save the data in the compressed +format, saving much disk space, and later use a codec to convert the +images to the X Windows screen format when the video is to be displayed. + +Even so, ultimately, some standard formats are needed, so the V4L2 +specification would not be complete without well-defined standard +formats. + +The V4L2 standard formats are mainly uncompressed formats. The pixels +are always arranged in memory from left to right, and from top to +bottom. The first byte of data in the image buffer is always for the +leftmost pixel of the topmost row. Following that is the pixel +immediately to its right, and so on until the end of the top row of +pixels. Following the rightmost pixel of the row there may be zero or +more bytes of padding to guarantee that each row of pixel data has a +certain alignment. Following the pad bytes, if any, is data for the +leftmost pixel of the second row from the top, and so on. The last row +has just as many pad bytes after it as the other rows. + +In V4L2 each format has an identifier which looks like ``PIX_FMT_XXX``, +defined in the :ref:`videodev2.h ` header file. These +identifiers represent +:ref:`four character (FourCC) codes ` which are also +listed below, however they are not the same as those used in the Windows +world. + +For some formats, data is stored in separate, discontiguous memory +buffers. Those formats are identified by a separate set of FourCC codes +and are referred to as "multi-planar formats". For example, a +:ref:`YUV422 ` frame is normally stored in one +memory buffer, but it can also be placed in two or three separate +buffers, with Y component in one buffer and CbCr components in another +in the 2-planar version or with each component in its own buffer in the +3-planar case. Those sub-buffers are referred to as "*planes*". diff --git a/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst b/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst new file mode 100644 index 000000000000..337e8188caf1 --- /dev/null +++ b/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst @@ -0,0 +1,99 @@ +.. -*- coding: utf-8; mode: rst -*- + +****************************** +Multi-planar format structures +****************************** + +The struct :c:type:`v4l2_plane_pix_format` structures define size +and layout for each of the planes in a multi-planar format. The +struct :c:type:`v4l2_pix_format_mplane` structure contains +information common to all planes (such as image width and height) and an +array of struct :c:type:`v4l2_plane_pix_format` structures, +describing all planes of that format. + + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. c:type:: v4l2_plane_pix_format + +.. flat-table:: struct v4l2_plane_pix_format + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``sizeimage`` + - Maximum size in bytes required for image data in this plane. + * - __u32 + - ``bytesperline`` + - Distance in bytes between the leftmost pixels in two adjacent + lines. See struct :c:type:`v4l2_pix_format`. + * - __u16 + - ``reserved[6]`` + - Reserved for future extensions. Should be zeroed by drivers and + applications. + + +.. tabularcolumns:: |p{4.4cm}|p{5.6cm}|p{7.5cm}| + +.. c:type:: v4l2_pix_format_mplane + +.. flat-table:: struct v4l2_pix_format_mplane + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``width`` + - Image width in pixels. See struct + :c:type:`v4l2_pix_format`. + * - __u32 + - ``height`` + - Image height in pixels. See struct + :c:type:`v4l2_pix_format`. + * - __u32 + - ``pixelformat`` + - The pixel format. Both single- and multi-planar four character + codes can be used. + * - enum :c:type:`v4l2_field` + - ``field`` + - See struct :c:type:`v4l2_pix_format`. + * - enum :c:type:`v4l2_colorspace` + - ``colorspace`` + - See struct :c:type:`v4l2_pix_format`. + * - struct :c:type:`v4l2_plane_pix_format` + - ``plane_fmt[VIDEO_MAX_PLANES]`` + - An array of structures describing format of each plane this pixel + format consists of. The number of valid entries in this array has + to be put in the ``num_planes`` field. + * - __u8 + - ``num_planes`` + - Number of planes (i.e. separate memory buffers) for this format + and the number of valid entries in the ``plane_fmt`` array. + * - __u8 + - ``flags`` + - Flags set by the application or driver, see :ref:`format-flags`. + * - enum :c:type:`v4l2_ycbcr_encoding` + - ``ycbcr_enc`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. + * - enum :c:type:`v4l2_hsv_encoding` + - ``hsv_enc`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. + * - enum :c:type:`v4l2_quantization` + - ``quantization`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. + * - enum :c:type:`v4l2_xfer_func` + - ``xfer_func`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. + * - __u8 + - ``reserved[7]`` + - Reserved for future extensions. Should be zeroed by drivers and + applications. diff --git a/Documentation/media/uapi/v4l/pixfmt-v4l2.rst b/Documentation/media/uapi/v4l/pixfmt-v4l2.rst new file mode 100644 index 000000000000..2ee164c25637 --- /dev/null +++ b/Documentation/media/uapi/v4l/pixfmt-v4l2.rst @@ -0,0 +1,138 @@ +.. -*- coding: utf-8; mode: rst -*- + +****************************** +Single-planar format structure +****************************** + +.. tabularcolumns:: |p{4.0cm}|p{2.5cm}|p{11.0cm}| + +.. c:type:: v4l2_pix_format + +.. cssclass:: longtable + +.. flat-table:: struct v4l2_pix_format + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``width`` + - Image width in pixels. + * - __u32 + - ``height`` + - Image height in pixels. If ``field`` is one of ``V4L2_FIELD_TOP``, + ``V4L2_FIELD_BOTTOM`` or ``V4L2_FIELD_ALTERNATE`` then height + refers to the number of lines in the field, otherwise it refers to + the number of lines in the frame (which is twice the field height + for interlaced formats). + * - :cspan:`2` Applications set these fields to request an image + size, drivers return the closest possible values. In case of + planar formats the ``width`` and ``height`` applies to the largest + plane. To avoid ambiguities drivers must return values rounded up + to a multiple of the scale factor of any smaller planes. For + example when the image format is YUV 4:2:0, ``width`` and + ``height`` must be multiples of two. + * - __u32 + - ``pixelformat`` + - The pixel format or type of compression, set by the application. + This is a little endian + :ref:`four character code `. V4L2 defines standard + RGB formats in :ref:`rgb-formats`, YUV formats in + :ref:`yuv-formats`, and reserved codes in + :ref:`reserved-formats` + * - enum :c:type::`v4l2_field` + - ``field`` + - Video images are typically interlaced. Applications can request to + capture or output only the top or bottom field, or both fields + interlaced or sequentially stored in one buffer or alternating in + separate buffers. Drivers return the actual field order selected. + For more details on fields see :ref:`field-order`. + * - __u32 + - ``bytesperline`` + - Distance in bytes between the leftmost pixels in two adjacent + lines. + * - :cspan:`2` + + Both applications and drivers can set this field to request + padding bytes at the end of each line. Drivers however may ignore + the value requested by the application, returning ``width`` times + bytes per pixel or a larger value required by the hardware. That + implies applications can just set this field to zero to get a + reasonable default. + + Video hardware may access padding bytes, therefore they must + reside in accessible memory. Consider cases where padding bytes + after the last line of an image cross a system page boundary. + Input devices may write padding bytes, the value is undefined. + Output devices ignore the contents of padding bytes. + + When the image format is planar the ``bytesperline`` value applies + to the first plane and is divided by the same factor as the + ``width`` field for the other planes. For example the Cb and Cr + planes of a YUV 4:2:0 image have half as many padding bytes + following each line as the Y plane. To avoid ambiguities drivers + must return a ``bytesperline`` value rounded up to a multiple of + the scale factor. + + For compressed formats the ``bytesperline`` value makes no sense. + Applications and drivers must set this to 0 in that case. + * - __u32 + - ``sizeimage`` + - Size in bytes of the buffer to hold a complete image, set by the + driver. Usually this is ``bytesperline`` times ``height``. When + the image consists of variable length compressed data this is the + maximum number of bytes required to hold an image. + * - enum :c:type:`v4l2_colorspace` + - ``colorspace`` + - This information supplements the ``pixelformat`` and must be set + by the driver for capture streams and by the application for + output streams, see :ref:`colorspaces`. + * - __u32 + - ``priv`` + - This field indicates whether the remaining fields of the + struct :c:type:`v4l2_pix_format`, also called the + extended fields, are valid. When set to + ``V4L2_PIX_FMT_PRIV_MAGIC``, it indicates that the extended fields + have been correctly initialized. When set to any other value it + indicates that the extended fields contain undefined values. + + Applications that wish to use the pixel format extended fields + must first ensure that the feature is supported by querying the + device for the :ref:`V4L2_CAP_EXT_PIX_FORMAT ` + capability. If the capability isn't set the pixel format extended + fields are not supported and using the extended fields will lead + to undefined results. + + To use the extended fields, applications must set the ``priv`` + field to ``V4L2_PIX_FMT_PRIV_MAGIC``, initialize all the extended + fields and zero the unused bytes of the + struct :c:type:`v4l2_format` ``raw_data`` field. + + When the ``priv`` field isn't set to ``V4L2_PIX_FMT_PRIV_MAGIC`` + drivers must act as if all the extended fields were set to zero. + On return drivers must set the ``priv`` field to + ``V4L2_PIX_FMT_PRIV_MAGIC`` and all the extended fields to + applicable values. + * - __u32 + - ``flags`` + - Flags set by the application or driver, see :ref:`format-flags`. + * - enum :c:type:`v4l2_ycbcr_encoding` + - ``ycbcr_enc`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. + * - enum :c:type:`v4l2_hsv_encoding` + - ``hsv_enc`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. + * - enum :c:type:`v4l2_quantization` + - ``quantization`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. + * - enum :c:type:`v4l2_xfer_func` + - ``xfer_func`` + - This information supplements the ``colorspace`` and must be set by + the driver for capture streams and by the application for output + streams, see :ref:`colorspaces`. diff --git a/Documentation/media/uapi/v4l/pixfmt.rst b/Documentation/media/uapi/v4l/pixfmt.rst index 00737152497b..2aa449e2da67 100644 --- a/Documentation/media/uapi/v4l/pixfmt.rst +++ b/Documentation/media/uapi/v4l/pixfmt.rst @@ -19,20 +19,19 @@ see also :ref:`VIDIOC_G_FBUF `.) .. toctree:: :maxdepth: 1 - pixfmt-002 - pixfmt-003 - pixfmt-004 - colorspaces - pixfmt-006 - pixfmt-007 - pixfmt-008 + pixfmt-v4l2 + pixfmt-v4l2-mplane + pixfmt-intro pixfmt-indexed pixfmt-rgb yuv-formats hsv-formats depth-formats - pixfmt-013 + pixfmt-compressed sdr-formats tch-formats meta-formats pixfmt-reserved + colorspaces + colorspaces-defs + colorspaces-details -- cgit