Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 136 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/vidioc-cropcap.rst b/Documentation/media/uapi/v4l/vidioc-cropcap.rst
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_CROPCAP:
+
+********************
+ioctl VIDIOC_CROPCAP
+********************
+
+Name
+====
+
+VIDIOC_CROPCAP - Information about the video cropping and scaling abilities
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, VIDIOC_CROPCAP, struct v4l2_cropcap *argp )
+    :name: VIDIOC_CROPCAP
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``argp``
+    Pointer to struct :c:type:`v4l2_cropcap`.
+
+
+Description
+===========
+
+Applications use this function to query the cropping limits, the pixel
+aspect of images and to calculate scale factors. They set the ``type``
+field of a v4l2_cropcap structure to the respective buffer (stream)
+type and call the :ref:`VIDIOC_CROPCAP` ioctl with a pointer to this
+structure. Drivers fill the rest of the structure. The results are
+constant except when switching the video standard. Remember this switch
+can occur implicit when switching the video input or output.
+
+This ioctl must be implemented for video capture or output devices that
+support cropping and/or scaling and/or have non-square pixels, and for
+overlay devices.
+
+.. c:type:: v4l2_cropcap
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct v4l2_cropcap
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u32
+      - ``type``
+      - Type of the data stream, set by the application. Only these types
+	are valid here: ``V4L2_BUF_TYPE_VIDEO_CAPTURE``, ``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``,
+	``V4L2_BUF_TYPE_VIDEO_OUTPUT``, ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE`` and
+	``V4L2_BUF_TYPE_VIDEO_OVERLAY``. See :c:type:`v4l2_buf_type` and the note above.
+    * - struct :ref:`v4l2_rect <v4l2-rect-crop>`
+      - ``bounds``
+      - Defines the window within capturing or output is possible, this
+	may exclude for example the horizontal and vertical blanking
+	areas. The cropping rectangle cannot exceed these limits. Width
+	and height are defined in pixels, the driver writer is free to
+	choose origin and units of the coordinate system in the analog
+	domain.
+    * - struct :ref:`v4l2_rect <v4l2-rect-crop>`
+      - ``defrect``
+      - Default cropping rectangle, it shall cover the "whole picture".
+	Assuming pixel aspect 1/1 this could be for example a 640 × 480
+	rectangle for NTSC, a 768 × 576 rectangle for PAL and SECAM
+	centered over the active picture area. The same co-ordinate system
+	as for ``bounds`` is used.
+    * - struct :c:type:`v4l2_fract`
+      - ``pixelaspect``
+      - This is the pixel aspect (y / x) when no scaling is applied, the
+	ratio of the actual sampling frequency and the frequency required
+	to get square pixels.
+
+	When cropping coordinates refer to square pixels, the driver sets
+	``pixelaspect`` to 1/1. Other common values are 54/59 for PAL and
+	SECAM, 11/10 for NTSC sampled according to [:ref:`itu601`].
+
+.. note::
+   Unfortunately in the case of multiplanar buffer types
+   (``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``)
+   this API was messed up with regards to how the :c:type:`v4l2_cropcap` ``type`` field
+   should be filled in. Some drivers only accepted the ``_MPLANE`` buffer type while
+   other drivers only accepted a non-multiplanar buffer type (i.e. without the
+   ``_MPLANE`` at the end).
+
+   Starting with kernel 4.13 both variations are allowed.
+
+
+
+.. _v4l2-rect-crop:
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct v4l2_rect
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __s32
+      - ``left``
+      - Horizontal offset of the top, left corner of the rectangle, in
+	pixels.
+    * - __s32
+      - ``top``
+      - Vertical offset of the top, left corner of the rectangle, in
+	pixels.
+    * - __u32
+      - ``width``
+      - Width of the rectangle, in pixels.
+    * - __u32
+      - ``height``
+      - Height of the rectangle, in pixels.
+
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+EINVAL
+    The struct :c:type:`v4l2_cropcap` ``type`` is
+    invalid.
+
+ENODATA
+    Cropping is not supported for this input or output.