64 lines
2.7 KiB
ReStructuredText
64 lines
2.7 KiB
ReStructuredText
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.. Permission is granted to copy, distribute and/or modify this
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.. document under the terms of the GNU Free Documentation License,
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.. Version 1.1 or any later version published by the Free Software
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.. Foundation, with no Invariant Sections, no Front-Cover Texts
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.. and no Back-Cover Texts. A copy of the license is included at
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.. Documentation/media/uapi/fdl-appendix.rst.
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..
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.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
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.. _image-process-controls:
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*******************************
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Image Process Control Reference
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*******************************
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The Image Process control class is intended for low-level control of
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image processing functions. Unlike ``V4L2_CID_IMAGE_SOURCE_CLASS``, the
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controls in this class affect processing the image, and do not control
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capturing of it.
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.. _image-process-control-id:
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Image Process Control IDs
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=========================
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``V4L2_CID_IMAGE_PROC_CLASS (class)``
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The IMAGE_PROC class descriptor.
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``V4L2_CID_LINK_FREQ (integer menu)``
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Data bus frequency. Together with the media bus pixel code, bus type
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(clock cycles per sample), the data bus frequency defines the pixel
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rate (``V4L2_CID_PIXEL_RATE``) in the pixel array (or possibly
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elsewhere, if the device is not an image sensor). The frame rate can
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be calculated from the pixel clock, image width and height and
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horizontal and vertical blanking. While the pixel rate control may
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be defined elsewhere than in the subdev containing the pixel array,
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the frame rate cannot be obtained from that information. This is
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because only on the pixel array it can be assumed that the vertical
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and horizontal blanking information is exact: no other blanking is
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allowed in the pixel array. The selection of frame rate is performed
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by selecting the desired horizontal and vertical blanking. The unit
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of this control is Hz.
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``V4L2_CID_PIXEL_RATE (64-bit integer)``
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Pixel rate in the source pads of the subdev. This control is
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read-only and its unit is pixels / second.
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``V4L2_CID_TEST_PATTERN (menu)``
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Some capture/display/sensor devices have the capability to generate
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test pattern images. These hardware specific test patterns can be
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used to test if a device is working properly.
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``V4L2_CID_DEINTERLACING_MODE (menu)``
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The video deinterlacing mode (such as Bob, Weave, ...). The menu items are
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driver specific and are documented in :ref:`v4l-drivers`.
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``V4L2_CID_DIGITAL_GAIN (integer)``
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Digital gain is the value by which all colour components
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are multiplied by. Typically the digital gain applied is the
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control value divided by e.g. 0x100, meaning that to get no
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digital gain the control value needs to be 0x100. The no-gain
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configuration is also typically the default.
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