xref: /linux/Documentation/userspace-api/media/v4l/ext-ctrls-image-process.rst (revision 778b8ebe5192e7a7f00563a7456517dfa63e1d90)
1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2.. c:namespace:: V4L
3
4.. _image-process-controls:
5
6*******************************
7Image Process Control Reference
8*******************************
9
10The Image Process control class is intended for low-level control of
11image processing functions. Unlike ``V4L2_CID_IMAGE_SOURCE_CLASS``, the
12controls in this class affect processing the image, and do not control
13capturing of it.
14
15
16.. _image-process-control-id:
17
18Image Process Control IDs
19=========================
20
21``V4L2_CID_IMAGE_PROC_CLASS (class)``
22    The IMAGE_PROC class descriptor.
23
24.. _v4l2-cid-link-freq:
25
26``V4L2_CID_LINK_FREQ (integer menu)``
27    The frequency of the data bus (e.g. parallel or CSI-2).
28
29.. _v4l2-cid-pixel-rate:
30
31``V4L2_CID_PIXEL_RATE (64-bit integer)``
32    Pixel sampling rate in the device's pixel array. This control is
33    read-only and its unit is pixels / second.
34
35    Some devices use horizontal and vertical blanking to configure the frame
36    rate. The frame rate can be calculated from the pixel rate, analogue crop
37    rectangle as well as horizontal and vertical blanking. The pixel rate
38    control may be present in a different sub-device than the blanking controls
39    and the analogue crop rectangle configuration.
40
41    The configuration of the frame rate is performed by selecting the desired
42    horizontal and vertical blanking. The unit of this control is Hz.
43
44``V4L2_CID_TEST_PATTERN (menu)``
45    Some capture/display/sensor devices have the capability to generate
46    test pattern images. These hardware specific test patterns can be
47    used to test if a device is working properly.
48
49``V4L2_CID_DEINTERLACING_MODE (menu)``
50    The video deinterlacing mode (such as Bob, Weave, ...). The menu items are
51    driver specific and are documented in :ref:`uapi-v4l-drivers`.
52
53``V4L2_CID_DIGITAL_GAIN (integer)``
54    Digital gain is the value by which all colour components
55    are multiplied by. Typically the digital gain applied is the
56    control value divided by e.g. 0x100, meaning that to get no
57    digital gain the control value needs to be 0x100. The no-gain
58    configuration is also typically the default.
59