1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2
3.. _image-process-controls:
4
5*******************************
6Image Process Control Reference
7*******************************
8
9The Image Process control class is intended for low-level control of
10image processing functions. Unlike ``V4L2_CID_IMAGE_SOURCE_CLASS``, the
11controls in this class affect processing the image, and do not control
12capturing of it.
13
14
15.. _image-process-control-id:
16
17Image Process Control IDs
18=========================
19
20``V4L2_CID_IMAGE_PROC_CLASS (class)``
21    The IMAGE_PROC class descriptor.
22
23``V4L2_CID_LINK_FREQ (integer menu)``
24    Data bus frequency. Together with the media bus pixel code, bus type
25    (clock cycles per sample), the data bus frequency defines the pixel
26    rate (``V4L2_CID_PIXEL_RATE``) in the pixel array (or possibly
27    elsewhere, if the device is not an image sensor). The frame rate can
28    be calculated from the pixel clock, image width and height and
29    horizontal and vertical blanking. While the pixel rate control may
30    be defined elsewhere than in the subdev containing the pixel array,
31    the frame rate cannot be obtained from that information. This is
32    because only on the pixel array it can be assumed that the vertical
33    and horizontal blanking information is exact: no other blanking is
34    allowed in the pixel array. The selection of frame rate is performed
35    by selecting the desired horizontal and vertical blanking. The unit
36    of this control is Hz.
37
38``V4L2_CID_PIXEL_RATE (64-bit integer)``
39    Pixel rate in the source pads of the subdev. This control is
40    read-only and its unit is pixels / second.
41
42``V4L2_CID_TEST_PATTERN (menu)``
43    Some capture/display/sensor devices have the capability to generate
44    test pattern images. These hardware specific test patterns can be
45    used to test if a device is working properly.
46
47``V4L2_CID_DEINTERLACING_MODE (menu)``
48    The video deinterlacing mode (such as Bob, Weave, ...). The menu items are
49    driver specific and are documented in :ref:`uapi-v4l-drivers`.
50
51``V4L2_CID_DIGITAL_GAIN (integer)``
52    Digital gain is the value by which all colour components
53    are multiplied by. Typically the digital gain applied is the
54    control value divided by e.g. 0x100, meaning that to get no
55    digital gain the control value needs to be 0x100. The no-gain
56    configuration is also typically the default.
57