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