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1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later2 3.. _image-source-controls:4 5******************************6Image Source Control Reference7******************************8 9The Image Source control class is intended for low-level control of10image source devices such as image sensors. The devices feature an11analogue to digital converter and a bus transmitter to transmit the12image data out of the device.13 14 15.. _image-source-control-id:16 17Image Source Control IDs18========================19 20``V4L2_CID_IMAGE_SOURCE_CLASS (class)``21 The IMAGE_SOURCE class descriptor.22 23``V4L2_CID_VBLANK (integer)``24 Vertical blanking. The idle period after every frame during which no25 image data is produced. The unit of vertical blanking is a line.26 Every line has length of the image width plus horizontal blanking at27 the pixel rate defined by ``V4L2_CID_PIXEL_RATE`` control in the28 same sub-device.29 30``V4L2_CID_HBLANK (integer)``31 Horizontal blanking. The idle period after every line of image data32 during which no image data is produced. The unit of horizontal33 blanking is pixels.34 35``V4L2_CID_ANALOGUE_GAIN (integer)``36 Analogue gain is gain affecting all colour components in the pixel37 matrix. The gain operation is performed in the analogue domain38 before A/D conversion.39 40``V4L2_CID_TEST_PATTERN_RED (integer)``41 Test pattern red colour component.42 43``V4L2_CID_TEST_PATTERN_GREENR (integer)``44 Test pattern green (next to red) colour component.45 46``V4L2_CID_TEST_PATTERN_BLUE (integer)``47 Test pattern blue colour component.48 49``V4L2_CID_TEST_PATTERN_GREENB (integer)``50 Test pattern green (next to blue) colour component.51 52``V4L2_CID_UNIT_CELL_SIZE (struct)``53 This control returns the unit cell size in nanometers. The struct54 :c:type:`v4l2_area` provides the width and the height in separate55 fields to take into consideration asymmetric pixels.56 This control does not take into consideration any possible hardware57 binning.58 The unit cell consists of the whole area of the pixel, sensitive and59 non-sensitive.60 This control is required for automatic calibration of sensors/cameras.61 62.. c:type:: v4l2_area63 64.. flat-table:: struct v4l2_area65 :header-rows: 066 :stub-columns: 067 :widths: 1 1 268 69 * - __u3270 - ``width``71 - Width of the area.72 * - __u3273 - ``height``74 - Height of the area.75 76``V4L2_CID_NOTIFY_GAINS (integer array)``77 The sensor is notified what gains will be applied to the different78 colour channels by subsequent processing (such as by an ISP). The79 sensor is merely informed of these values in case it performs80 processing that requires them, but it does not apply them itself to81 the output pixels.82 83 Currently it is defined only for Bayer sensors, and is an array84 control taking 4 gain values, being the gains for each of the85 Bayer channels. The gains are always in the order B, Gb, Gr and R,86 irrespective of the exact Bayer order of the sensor itself.87 88 The use of an array allows this control to be extended to sensors89 with, for example, non-Bayer CFAs (colour filter arrays).90 91 The units for the gain values are linear, with the default value92 representing a gain of exactly 1.0. For example, if this default value93 is reported as being (say) 128, then a value of 192 would represent94 a gain of exactly 1.5.95