xref: /linux/Documentation/userspace-api/media/v4l/ext-ctrls-image-process.rst (revision bba2c3615bd6cfee7456d1130f2e6b01b3f4e9ba)
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 fundamental frequency of the operating symbol rate (serial interfaces
28    such as CSI-2) or the sampling rate (parallel interfaces such as DVP or
29    Bt.565) of the data interface. For CSI-2, the frequency is equal to
30    _1 / (2 * UI)_.
31
32.. _v4l2-cid-pixel-rate:
33
34``V4L2_CID_PIXEL_RATE (64-bit integer)``
35    Pixel sampling rate in the device's pixel array. This control is
36    read-only and its unit is pixels / second.
37
38    Some devices use horizontal and vertical blanking to configure the frame
39    rate. The frame rate can be calculated from the pixel rate, analogue crop
40    rectangle as well as horizontal and vertical blanking. The pixel rate
41    control may be present in a different sub-device than the blanking controls
42    and the analogue crop rectangle configuration.
43
44    The configuration of the frame rate is performed by selecting the desired
45    horizontal and vertical blanking. The unit of this control is Hz.
46
47``V4L2_CID_TEST_PATTERN (menu)``
48    Some capture/display/sensor devices have the capability to generate
49    test pattern images. These hardware specific test patterns can be
50    used to test if a device is working properly.
51
52``V4L2_CID_DEINTERLACING_MODE (menu)``
53    The video deinterlacing mode (such as Bob, Weave, ...). The menu items are
54    driver specific and are documented in :ref:`uapi-v4l-drivers`.
55
56``V4L2_CID_DIGITAL_GAIN (integer)``
57    Digital gain is the value by which all colour components
58    are multiplied by. Typically the digital gain applied is the
59    control value divided by e.g. 0x100, meaning that to get no
60    digital gain the control value needs to be 0x100. The no-gain
61    configuration is also typically the default.
62