| Olivier Deprez | 157378f | 2022-04-04 15:47:50 +0200 | [diff] [blame^] | 1 | .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later |
| 2 | |
| 3 | .. _image-process-controls: |
| 4 | |
| 5 | ******************************* |
| 6 | Image Process Control Reference |
| 7 | ******************************* |
| 8 | |
| 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 |
| 12 | capturing of it. |
| 13 | |
| 14 | |
| 15 | .. _image-process-control-id: |
| 16 | |
| 17 | Image Process Control IDs |
| 18 | ========================= |
| 19 | |
| 20 | ``V4L2_CID_IMAGE_PROC_CLASS (class)`` |
| 21 | The IMAGE_PROC class descriptor. |
| 22 | |
| 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. |
| 37 | |
| 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. |
| 41 | |
| 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. |
| 46 | |
| 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`. |
| 50 | |
| 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. |