Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 240 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
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+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+******************************
+Single-planar format structure
+******************************
+
+.. tabularcolumns:: |p{4.0cm}|p{2.6cm}|p{10.7cm}|
+
+.. 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.
+
+	For compressed formats that contain the resolution information encoded
+	inside the stream, when fed to a stateful mem2mem decoder, the fields
+	may be zero to rely on the decoder to detect the right values. For more
+	details see :ref:`decoder` and format descriptions.
+
+	For compressed formats on the CAPTURE side of a stateful mem2mem
+	encoder, the fields must be zero, since the coded size is expected to
+	be calculated internally by the encoder itself, based on the OUTPUT
+	side. For more details see :ref:`encoder` and format descriptions.
+    * - __u32
+      - ``pixelformat``
+      - The pixel format or type of compression, set by the application.
+	This is a little endian
+	:ref:`four character code <v4l2-fourcc>`. V4L2 defines standard
+	RGB formats in :ref:`pixfmt-rgb`, YUV formats in
+	:ref:`yuv-formats`, and reserved codes in
+	:ref:`reserved-formats`
+    * - __u32
+      - ``field``
+      - Field order, from enum :c:type:`v4l2_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
+	number of bytes required by the codec to support the worst-case
+	compression scenario.
+
+	The driver will set the value for uncompressed images.
+
+	Clients are allowed to set the sizeimage field for variable length
+	compressed data flagged with ``V4L2_FMT_FLAG_COMPRESSED`` at
+	:ref:`VIDIOC_ENUM_FMT`, but the driver may ignore it and set the
+	value itself, or it may modify the provided value based on
+	alignment requirements or minimum/maximum size requirements.
+	If the client wants to leave this to the driver, then it should
+	set sizeimage to 0.
+    * - __u32
+      - ``colorspace``
+      - Image colorspace, from enum :c:type:`v4l2_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`. If the application sets the
+	flag ``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific colorspace
+	for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported colorspace.
+	The driver indicates that colorspace conversion is supported by setting
+	the flag V4L2_FMT_FLAG_CSC_COLORSPACE in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
+    * - __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 <querycap>`
+	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`.
+    * - union {
+      - (anonymous)
+    * - __u32
+      - ``ycbcr_enc``
+      - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
+        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`. If the application sets the
+	flag ``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific Y'CbCr encoding
+	for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported encoding.
+	This field is ignored for HSV pixelformats. The driver indicates that
+	ycbcr_enc conversion is supported by setting the flag
+	V4L2_FMT_FLAG_CSC_YCBCR_ENC in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
+    * - __u32
+      - ``hsv_enc``
+      - HSV encoding, from enum :c:type:`v4l2_hsv_encoding`.
+        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`. If the application sets the flag
+	``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set this
+	field for a capture stream to request a specific HSV encoding for the
+	captured image data. If the driver cannot handle requested
+	conversion, it will return another supported encoding.
+	This field is ignored for non-HSV pixelformats. The driver indicates
+	that hsv_enc conversion is supported by setting the flag
+	V4L2_FMT_FLAG_CSC_HSV_ENC in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
+    * - }
+      -
+    * - __u32
+      - ``quantization``
+      - Quantization range, from enum :c:type:`v4l2_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`. If the application sets the flag
+	``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific quantization
+	range for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported quantization.
+	The driver indicates that quantization conversion is supported by setting
+	the flag V4L2_FMT_FLAG_CSC_QUANTIZATION in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
+    * - __u32
+      - ``xfer_func``
+      - Transfer function, from enum :c:type:`v4l2_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`. If the application sets the flag
+	``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific transfer function
+	for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported transfer function.
+	The driver indicates that xfer_func conversion is supported by setting
+	the flag V4L2_FMT_FLAG_CSC_XFER_FUNC in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
+
+.. tabularcolumns:: |p{6.8cm}|p{2.3cm}|p{8.2cm}|
+
+.. _format-flags:
+
+.. flat-table:: Format Flags
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+    * - ``V4L2_PIX_FMT_FLAG_PREMUL_ALPHA``
+      - 0x00000001
+      - The color values are premultiplied by the alpha channel value. For
+        example, if a light blue pixel with 50% transparency was described
+	by RGBA values (128, 192, 255, 128), the same pixel described with
+	premultiplied colors would be described by RGBA values (64, 96,
+	128, 128)
+    * .. _`v4l2-pix-fmt-flag-set-csc`:
+
+      - ``V4L2_PIX_FMT_FLAG_SET_CSC``
+      - 0x00000002
+      - Set by the application. It is only used for capture and is
+        ignored for output streams. If set, then request the device to do
+	colorspace conversion from the received colorspace to the requested
+	colorspace values. If the colorimetry field (``colorspace``, ``xfer_func``,
+	``ycbcr_enc``, ``hsv_enc`` or ``quantization``) is set to ``*_DEFAULT``,
+	then that colorimetry setting will remain unchanged from what was received.
+	So in order to change the quantization, only the ``quantization`` field shall
+	be set to non default value (``V4L2_QUANTIZATION_FULL_RANGE`` or
+	``V4L2_QUANTIZATION_LIM_RANGE``) and all other colorimetry fields shall
+	be set to ``*_DEFAULT``.
+
+	To check which conversions are supported by the hardware for the current
+	pixel format, see :ref:`fmtdesc-flags`.