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 (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.
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.
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.
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`.
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.