1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
3 .. _image-process-controls:
5 *******************************
6 Image Process Control Reference
7 *******************************
9 The Image Process control class is intended for low-level control of
10 image processing functions. Unlike ``V4L2_CID_IMAGE_SOURCE_CLASS``, the
11 controls in this class affect processing the image, and do not control
15 .. _image-process-control-id:
17 Image Process Control IDs
18 =========================
20 ``V4L2_CID_IMAGE_PROC_CLASS (class)``
21 The IMAGE_PROC class descriptor.
23 .. _v4l2-cid-link-freq:
25 ``V4L2_CID_LINK_FREQ (integer menu)``
26 Data bus frequency. Together with the media bus pixel code, bus type
27 (clock cycles per sample), the data bus frequency defines the pixel
28 rate (``V4L2_CID_PIXEL_RATE``) in the pixel array (or possibly
29 elsewhere, if the device is not an image sensor). The frame rate can
30 be calculated from the pixel clock, image width and height and
31 horizontal and vertical blanking. While the pixel rate control may
32 be defined elsewhere than in the subdev containing the pixel array,
33 the frame rate cannot be obtained from that information. This is
34 because only on the pixel array it can be assumed that the vertical
35 and horizontal blanking information is exact: no other blanking is
36 allowed in the pixel array. The selection of frame rate is performed
37 by selecting the desired horizontal and vertical blanking. The unit
38 of this control is Hz.
40 ``V4L2_CID_PIXEL_RATE (64-bit integer)``
41 Pixel rate in the source pads of the subdev. This control is
42 read-only and its unit is pixels / second.
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.
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`.
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.