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1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later2 3.. _camera-controls:4 5************************6Camera Control Reference7************************8 9The Camera class includes controls for mechanical (or equivalent10digital) features of a device such as controllable lenses or sensors.11 12 13.. _camera-control-id:14 15Camera Control IDs16==================17 18``V4L2_CID_CAMERA_CLASS (class)``19 The Camera class descriptor. Calling20 :ref:`VIDIOC_QUERYCTRL` for this control will21 return a description of this control class.22 23.. _v4l2-exposure-auto-type:24 25``V4L2_CID_EXPOSURE_AUTO``26 (enum)27 28enum v4l2_exposure_auto_type -29 Enables automatic adjustments of the exposure time and/or iris30 aperture. The effect of manual changes of the exposure time or iris31 aperture while these features are enabled is undefined, drivers32 should ignore such requests. Possible values are:33 34 35.. tabularcolumns:: |p{7.1cm}|p{10.4cm}|36 37.. flat-table::38 :header-rows: 039 :stub-columns: 040 41 * - ``V4L2_EXPOSURE_AUTO``42 - Automatic exposure time, automatic iris aperture.43 * - ``V4L2_EXPOSURE_MANUAL``44 - Manual exposure time, manual iris.45 * - ``V4L2_EXPOSURE_SHUTTER_PRIORITY``46 - Manual exposure time, auto iris.47 * - ``V4L2_EXPOSURE_APERTURE_PRIORITY``48 - Auto exposure time, manual iris.49 50 51 52``V4L2_CID_EXPOSURE_ABSOLUTE (integer)``53 Determines the exposure time of the camera sensor. The exposure time54 is limited by the frame interval. Drivers should interpret the55 values as 100 µs units, where the value 1 stands for 1/10000th of a56 second, 10000 for 1 second and 100000 for 10 seconds.57 58``V4L2_CID_EXPOSURE_AUTO_PRIORITY (boolean)``59 When ``V4L2_CID_EXPOSURE_AUTO`` is set to ``AUTO`` or60 ``APERTURE_PRIORITY``, this control determines if the device may61 dynamically vary the frame rate. By default this feature is disabled62 (0) and the frame rate must remain constant.63 64``V4L2_CID_AUTO_EXPOSURE_BIAS (integer menu)``65 Determines the automatic exposure compensation, it is effective only66 when ``V4L2_CID_EXPOSURE_AUTO`` control is set to ``AUTO``,67 ``SHUTTER_PRIORITY`` or ``APERTURE_PRIORITY``. It is expressed in68 terms of EV, drivers should interpret the values as 0.001 EV units,69 where the value 1000 stands for +1 EV.70 71 Increasing the exposure compensation value is equivalent to72 decreasing the exposure value (EV) and will increase the amount of73 light at the image sensor. The camera performs the exposure74 compensation by adjusting absolute exposure time and/or aperture.75 76.. _v4l2-exposure-metering:77 78``V4L2_CID_EXPOSURE_METERING``79 (enum)80 81enum v4l2_exposure_metering -82 Determines how the camera measures the amount of light available for83 the frame exposure. Possible values are:84 85.. tabularcolumns:: |p{8.7cm}|p{8.7cm}|86 87.. flat-table::88 :header-rows: 089 :stub-columns: 090 91 * - ``V4L2_EXPOSURE_METERING_AVERAGE``92 - Use the light information coming from the entire frame and average93 giving no weighting to any particular portion of the metered area.94 * - ``V4L2_EXPOSURE_METERING_CENTER_WEIGHTED``95 - Average the light information coming from the entire frame giving96 priority to the center of the metered area.97 * - ``V4L2_EXPOSURE_METERING_SPOT``98 - Measure only very small area at the center of the frame.99 * - ``V4L2_EXPOSURE_METERING_MATRIX``100 - A multi-zone metering. The light intensity is measured in several101 points of the frame and the results are combined. The algorithm of102 the zones selection and their significance in calculating the103 final value is device dependent.104 105 106 107``V4L2_CID_PAN_RELATIVE (integer)``108 This control turns the camera horizontally by the specified amount.109 The unit is undefined. A positive value moves the camera to the110 right (clockwise when viewed from above), a negative value to the111 left. A value of zero does not cause motion. This is a write-only112 control.113 114``V4L2_CID_TILT_RELATIVE (integer)``115 This control turns the camera vertically by the specified amount.116 The unit is undefined. A positive value moves the camera up, a117 negative value down. A value of zero does not cause motion. This is118 a write-only control.119 120``V4L2_CID_PAN_RESET (button)``121 When this control is set, the camera moves horizontally to the122 default position.123 124``V4L2_CID_TILT_RESET (button)``125 When this control is set, the camera moves vertically to the default126 position.127 128``V4L2_CID_PAN_ABSOLUTE (integer)``129 This control turns the camera horizontally to the specified130 position. Positive values move the camera to the right (clockwise131 when viewed from above), negative values to the left. Drivers should132 interpret the values as arc seconds, with valid values between -180133 * 3600 and +180 * 3600 inclusive.134 135``V4L2_CID_TILT_ABSOLUTE (integer)``136 This control turns the camera vertically to the specified position.137 Positive values move the camera up, negative values down. Drivers138 should interpret the values as arc seconds, with valid values139 between -180 * 3600 and +180 * 3600 inclusive.140 141``V4L2_CID_FOCUS_ABSOLUTE (integer)``142 This control sets the focal point of the camera to the specified143 position. The unit is undefined. Positive values set the focus144 closer to the camera, negative values towards infinity.145 146``V4L2_CID_FOCUS_RELATIVE (integer)``147 This control moves the focal point of the camera by the specified148 amount. The unit is undefined. Positive values move the focus closer149 to the camera, negative values towards infinity. This is a150 write-only control.151 152``V4L2_CID_FOCUS_AUTO (boolean)``153 Enables continuous automatic focus adjustments. The effect of manual154 focus adjustments while this feature is enabled is undefined,155 drivers should ignore such requests.156 157``V4L2_CID_AUTO_FOCUS_START (button)``158 Starts single auto focus process. The effect of setting this control159 when ``V4L2_CID_FOCUS_AUTO`` is set to ``TRUE`` (1) is undefined,160 drivers should ignore such requests.161 162``V4L2_CID_AUTO_FOCUS_STOP (button)``163 Aborts automatic focusing started with ``V4L2_CID_AUTO_FOCUS_START``164 control. It is effective only when the continuous autofocus is165 disabled, that is when ``V4L2_CID_FOCUS_AUTO`` control is set to166 ``FALSE`` (0).167 168.. _v4l2-auto-focus-status:169 170``V4L2_CID_AUTO_FOCUS_STATUS (bitmask)``171 The automatic focus status. This is a read-only control.172 173 Setting ``V4L2_LOCK_FOCUS`` lock bit of the ``V4L2_CID_3A_LOCK``174 control may stop updates of the ``V4L2_CID_AUTO_FOCUS_STATUS``175 control value.176 177.. tabularcolumns:: |p{6.8cm}|p{10.7cm}|178 179.. flat-table::180 :header-rows: 0181 :stub-columns: 0182 183 * - ``V4L2_AUTO_FOCUS_STATUS_IDLE``184 - Automatic focus is not active.185 * - ``V4L2_AUTO_FOCUS_STATUS_BUSY``186 - Automatic focusing is in progress.187 * - ``V4L2_AUTO_FOCUS_STATUS_REACHED``188 - Focus has been reached.189 * - ``V4L2_AUTO_FOCUS_STATUS_FAILED``190 - Automatic focus has failed, the driver will not transition from191 this state until another action is performed by an application.192 193 194 195.. _v4l2-auto-focus-range:196 197``V4L2_CID_AUTO_FOCUS_RANGE``198 (enum)199 200enum v4l2_auto_focus_range -201 Determines auto focus distance range for which lens may be adjusted.202 203.. tabularcolumns:: |p{6.9cm}|p{10.6cm}|204 205.. flat-table::206 :header-rows: 0207 :stub-columns: 0208 209 * - ``V4L2_AUTO_FOCUS_RANGE_AUTO``210 - The camera automatically selects the focus range.211 * - ``V4L2_AUTO_FOCUS_RANGE_NORMAL``212 - Normal distance range, limited for best automatic focus213 performance.214 * - ``V4L2_AUTO_FOCUS_RANGE_MACRO``215 - Macro (close-up) auto focus. The camera will use its minimum216 possible distance for auto focus.217 * - ``V4L2_AUTO_FOCUS_RANGE_INFINITY``218 - The lens is set to focus on an object at infinite distance.219 220 221 222``V4L2_CID_ZOOM_ABSOLUTE (integer)``223 Specify the objective lens focal length as an absolute value. The224 zoom unit is driver-specific and its value should be a positive225 integer.226 227``V4L2_CID_ZOOM_RELATIVE (integer)``228 Specify the objective lens focal length relatively to the current229 value. Positive values move the zoom lens group towards the230 telephoto direction, negative values towards the wide-angle231 direction. The zoom unit is driver-specific. This is a write-only232 control.233 234``V4L2_CID_ZOOM_CONTINUOUS (integer)``235 Move the objective lens group at the specified speed until it236 reaches physical device limits or until an explicit request to stop237 the movement. A positive value moves the zoom lens group towards the238 telephoto direction. A value of zero stops the zoom lens group239 movement. A negative value moves the zoom lens group towards the240 wide-angle direction. The zoom speed unit is driver-specific.241 242``V4L2_CID_IRIS_ABSOLUTE (integer)``243 This control sets the camera's aperture to the specified value. The244 unit is undefined. Larger values open the iris wider, smaller values245 close it.246 247``V4L2_CID_IRIS_RELATIVE (integer)``248 This control modifies the camera's aperture by the specified amount.249 The unit is undefined. Positive values open the iris one step250 further, negative values close it one step further. This is a251 write-only control.252 253``V4L2_CID_PRIVACY (boolean)``254 Prevent video from being acquired by the camera. When this control255 is set to ``TRUE`` (1), no image can be captured by the camera.256 Common means to enforce privacy are mechanical obturation of the257 sensor and firmware image processing, but the device is not258 restricted to these methods. Devices that implement the privacy259 control must support read access and may support write access.260 261``V4L2_CID_BAND_STOP_FILTER (integer)``262 Switch the band-stop filter of a camera sensor on or off, or specify263 its strength. Such band-stop filters can be used, for example, to264 filter out the fluorescent light component.265 266.. _v4l2-auto-n-preset-white-balance:267 268``V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE``269 (enum)270 271enum v4l2_auto_n_preset_white_balance -272 Sets white balance to automatic, manual or a preset. The presets273 determine color temperature of the light as a hint to the camera for274 white balance adjustments resulting in most accurate color275 representation. The following white balance presets are listed in276 order of increasing color temperature.277 278.. tabularcolumns:: |p{7.4cm}|p{10.1cm}|279 280.. flat-table::281 :header-rows: 0282 :stub-columns: 0283 284 * - ``V4L2_WHITE_BALANCE_MANUAL``285 - Manual white balance.286 * - ``V4L2_WHITE_BALANCE_AUTO``287 - Automatic white balance adjustments.288 * - ``V4L2_WHITE_BALANCE_INCANDESCENT``289 - White balance setting for incandescent (tungsten) lighting. It290 generally cools down the colors and corresponds approximately to291 2500...3500 K color temperature range.292 * - ``V4L2_WHITE_BALANCE_FLUORESCENT``293 - White balance preset for fluorescent lighting. It corresponds294 approximately to 4000...5000 K color temperature.295 * - ``V4L2_WHITE_BALANCE_FLUORESCENT_H``296 - With this setting the camera will compensate for fluorescent H297 lighting.298 * - ``V4L2_WHITE_BALANCE_HORIZON``299 - White balance setting for horizon daylight. It corresponds300 approximately to 5000 K color temperature.301 * - ``V4L2_WHITE_BALANCE_DAYLIGHT``302 - White balance preset for daylight (with clear sky). It corresponds303 approximately to 5000...6500 K color temperature.304 * - ``V4L2_WHITE_BALANCE_FLASH``305 - With this setting the camera will compensate for the flash light.306 It slightly warms up the colors and corresponds roughly to307 5000...5500 K color temperature.308 * - ``V4L2_WHITE_BALANCE_CLOUDY``309 - White balance preset for moderately overcast sky. This option310 corresponds approximately to 6500...8000 K color temperature311 range.312 * - ``V4L2_WHITE_BALANCE_SHADE``313 - White balance preset for shade or heavily overcast sky. It314 corresponds approximately to 9000...10000 K color temperature.315 316 317 318.. _v4l2-wide-dynamic-range:319 320``V4L2_CID_WIDE_DYNAMIC_RANGE (boolean)``321 Enables or disables the camera's wide dynamic range feature. This322 feature allows to obtain clear images in situations where intensity323 of the illumination varies significantly throughout the scene, i.e.324 there are simultaneously very dark and very bright areas. It is most325 commonly realized in cameras by combining two subsequent frames with326 different exposure times. [#f1]_327 328.. _v4l2-image-stabilization:329 330``V4L2_CID_IMAGE_STABILIZATION (boolean)``331 Enables or disables image stabilization.332 333``V4L2_CID_ISO_SENSITIVITY (integer menu)``334 Determines ISO equivalent of an image sensor indicating the sensor's335 sensitivity to light. The numbers are expressed in arithmetic scale,336 as per :ref:`iso12232` standard, where doubling the sensor337 sensitivity is represented by doubling the numerical ISO value.338 Applications should interpret the values as standard ISO values339 multiplied by 1000, e.g. control value 800 stands for ISO 0.8.340 Drivers will usually support only a subset of standard ISO values.341 The effect of setting this control while the342 ``V4L2_CID_ISO_SENSITIVITY_AUTO`` control is set to a value other343 than ``V4L2_CID_ISO_SENSITIVITY_MANUAL`` is undefined, drivers344 should ignore such requests.345 346.. _v4l2-iso-sensitivity-auto-type:347 348``V4L2_CID_ISO_SENSITIVITY_AUTO``349 (enum)350 351enum v4l2_iso_sensitivity_type -352 Enables or disables automatic ISO sensitivity adjustments.353 354 355 356.. flat-table::357 :header-rows: 0358 :stub-columns: 0359 360 * - ``V4L2_CID_ISO_SENSITIVITY_MANUAL``361 - Manual ISO sensitivity.362 * - ``V4L2_CID_ISO_SENSITIVITY_AUTO``363 - Automatic ISO sensitivity adjustments.364 365 366 367.. _v4l2-scene-mode:368 369``V4L2_CID_SCENE_MODE``370 (enum)371 372enum v4l2_scene_mode -373 This control allows to select scene programs as the camera automatic374 modes optimized for common shooting scenes. Within these modes the375 camera determines best exposure, aperture, focusing, light metering,376 white balance and equivalent sensitivity. The controls of those377 parameters are influenced by the scene mode control. An exact378 behavior in each mode is subject to the camera specification.379 380 When the scene mode feature is not used, this control should be set381 to ``V4L2_SCENE_MODE_NONE`` to make sure the other possibly related382 controls are accessible. The following scene programs are defined:383 384.. raw:: latex385 386 \small387 388.. tabularcolumns:: |p{5.9cm}|p{11.6cm}|389 390.. cssclass:: longtable391 392.. flat-table::393 :header-rows: 0394 :stub-columns: 0395 396 * - ``V4L2_SCENE_MODE_NONE``397 - The scene mode feature is disabled.398 * - ``V4L2_SCENE_MODE_BACKLIGHT``399 - Backlight. Compensates for dark shadows when light is coming from400 behind a subject, also by automatically turning on the flash.401 * - ``V4L2_SCENE_MODE_BEACH_SNOW``402 - Beach and snow. This mode compensates for all-white or bright403 scenes, which tend to look gray and low contrast, when camera's404 automatic exposure is based on an average scene brightness. To405 compensate, this mode automatically slightly overexposes the406 frames. The white balance may also be adjusted to compensate for407 the fact that reflected snow looks bluish rather than white.408 * - ``V4L2_SCENE_MODE_CANDLELIGHT``409 - Candle light. The camera generally raises the ISO sensitivity and410 lowers the shutter speed. This mode compensates for relatively411 close subject in the scene. The flash is disabled in order to412 preserve the ambiance of the light.413 * - ``V4L2_SCENE_MODE_DAWN_DUSK``414 - Dawn and dusk. Preserves the colors seen in low natural light415 before dusk and after down. The camera may turn off the flash, and416 automatically focus at infinity. It will usually boost saturation417 and lower the shutter speed.418 * - ``V4L2_SCENE_MODE_FALL_COLORS``419 - Fall colors. Increases saturation and adjusts white balance for420 color enhancement. Pictures of autumn leaves get saturated reds421 and yellows.422 * - ``V4L2_SCENE_MODE_FIREWORKS``423 - Fireworks. Long exposure times are used to capture the expanding424 burst of light from a firework. The camera may invoke image425 stabilization.426 * - ``V4L2_SCENE_MODE_LANDSCAPE``427 - Landscape. The camera may choose a small aperture to provide deep428 depth of field and long exposure duration to help capture detail429 in dim light conditions. The focus is fixed at infinity. Suitable430 for distant and wide scenery.431 * - ``V4L2_SCENE_MODE_NIGHT``432 - Night, also known as Night Landscape. Designed for low light433 conditions, it preserves detail in the dark areas without blowing434 out bright objects. The camera generally sets itself to a435 medium-to-high ISO sensitivity, with a relatively long exposure436 time, and turns flash off. As such, there will be increased image437 noise and the possibility of blurred image.438 * - ``V4L2_SCENE_MODE_PARTY_INDOOR``439 - Party and indoor. Designed to capture indoor scenes that are lit440 by indoor background lighting as well as the flash. The camera441 usually increases ISO sensitivity, and adjusts exposure for the442 low light conditions.443 * - ``V4L2_SCENE_MODE_PORTRAIT``444 - Portrait. The camera adjusts the aperture so that the depth of445 field is reduced, which helps to isolate the subject against a446 smooth background. Most cameras recognize the presence of faces in447 the scene and focus on them. The color hue is adjusted to enhance448 skin tones. The intensity of the flash is often reduced.449 * - ``V4L2_SCENE_MODE_SPORTS``450 - Sports. Significantly increases ISO and uses a fast shutter speed451 to freeze motion of rapidly-moving subjects. Increased image noise452 may be seen in this mode.453 * - ``V4L2_SCENE_MODE_SUNSET``454 - Sunset. Preserves deep hues seen in sunsets and sunrises. It bumps455 up the saturation.456 * - ``V4L2_SCENE_MODE_TEXT``457 - Text. It applies extra contrast and sharpness, it is typically a458 black-and-white mode optimized for readability. Automatic focus459 may be switched to close-up mode and this setting may also involve460 some lens-distortion correction.461 462.. raw:: latex463 464 \normalsize465 466 467``V4L2_CID_3A_LOCK (bitmask)``468 This control locks or unlocks the automatic focus, exposure and469 white balance. The automatic adjustments can be paused independently470 by setting the corresponding lock bit to 1. The camera then retains471 the settings until the lock bit is cleared. The following lock bits472 are defined:473 474 When a given algorithm is not enabled, drivers should ignore475 requests to lock it and should return no error. An example might be476 an application setting bit ``V4L2_LOCK_WHITE_BALANCE`` when the477 ``V4L2_CID_AUTO_WHITE_BALANCE`` control is set to ``FALSE``. The478 value of this control may be changed by exposure, white balance or479 focus controls.480 481 482 483.. flat-table::484 :header-rows: 0485 :stub-columns: 0486 487 * - ``V4L2_LOCK_EXPOSURE``488 - Automatic exposure adjustments lock.489 * - ``V4L2_LOCK_WHITE_BALANCE``490 - Automatic white balance adjustments lock.491 * - ``V4L2_LOCK_FOCUS``492 - Automatic focus lock.493 494 495 496``V4L2_CID_PAN_SPEED (integer)``497 This control turns the camera horizontally at the specific speed.498 The unit is undefined. A positive value moves the camera to the499 right (clockwise when viewed from above), a negative value to the500 left. A value of zero stops the motion if one is in progress and has501 no effect otherwise.502 503``V4L2_CID_TILT_SPEED (integer)``504 This control turns the camera vertically at the specified speed. The505 unit is undefined. A positive value moves the camera up, a negative506 value down. A value of zero stops the motion if one is in progress507 and has no effect otherwise.508 509.. _v4l2-camera-sensor-orientation:510 511``V4L2_CID_CAMERA_ORIENTATION (menu)``512 This read-only control describes the camera orientation by reporting its513 mounting position on the device where the camera is installed. The control514 value is constant and not modifiable by software. This control is515 particularly meaningful for devices which have a well defined orientation,516 such as phones, laptops and portable devices since the control is expressed517 as a position relative to the device's intended usage orientation. For518 example, a camera installed on the user-facing side of a phone, a tablet or519 a laptop device is said to be have ``V4L2_CAMERA_ORIENTATION_FRONT``520 orientation, while a camera installed on the opposite side of the front one521 is said to be have ``V4L2_CAMERA_ORIENTATION_BACK`` orientation. Camera522 sensors not directly attached to the device, or attached in a way that523 allows them to move freely, such as webcams and digital cameras, are said to524 have the ``V4L2_CAMERA_ORIENTATION_EXTERNAL`` orientation.525 526 527.. tabularcolumns:: |p{7.7cm}|p{9.8cm}|528 529.. flat-table::530 :header-rows: 0531 :stub-columns: 0532 533 * - ``V4L2_CAMERA_ORIENTATION_FRONT``534 - The camera is oriented towards the user facing side of the device.535 * - ``V4L2_CAMERA_ORIENTATION_BACK``536 - The camera is oriented towards the back facing side of the device.537 * - ``V4L2_CAMERA_ORIENTATION_EXTERNAL``538 - The camera is not directly attached to the device and is freely movable.539 540 541.. _v4l2-camera-sensor-rotation:542 543``V4L2_CID_CAMERA_SENSOR_ROTATION (integer)``544 This read-only control describes the rotation correction in degrees in the545 counter-clockwise direction to be applied to the captured images once546 captured to memory to compensate for the camera sensor mounting rotation.547 548 For a precise definition of the sensor mounting rotation refer to the549 extensive description of the 'rotation' properties in the device tree550 bindings file 'video-interfaces.txt'.551 552 A few examples are below reported, using a shark swimming from left to553 right in front of the user as the example scene to capture. ::554 555 0 X-axis556 0 +------------------------------------->557 !558 !559 !560 ! |\____)\___561 ! ) _____ __`<562 ! |/ )/563 !564 !565 !566 V567 Y-axis568 569 Example one - Webcam570 571 Assuming you can bring your laptop with you while swimming with sharks,572 the camera module of the laptop is installed on the user facing part of a573 laptop screen casing, and is typically used for video calls. The captured574 images are meant to be displayed in landscape mode (width > height) on the575 laptop screen.576 577 The camera is typically mounted upside-down to compensate the lens optical578 inversion effect. In this case the value of the579 V4L2_CID_CAMERA_SENSOR_ROTATION control is 0, no rotation is required to580 display images correctly to the user.581 582 If the camera sensor is not mounted upside-down it is required to compensate583 the lens optical inversion effect and the value of the584 V4L2_CID_CAMERA_SENSOR_ROTATION control is 180 degrees, as images will585 result rotated when captured to memory. ::586 587 +--------------------------------------+588 ! !589 ! !590 ! !591 ! __/(_____/| !592 ! >.___ ____ ( !593 ! \( \| !594 ! !595 ! !596 ! !597 +--------------------------------------+598 599 A software rotation correction of 180 degrees has to be applied to correctly600 display the image on the user screen. ::601 602 +--------------------------------------+603 ! !604 ! !605 ! !606 ! |\____)\___ !607 ! ) _____ __`< !608 ! |/ )/ !609 ! !610 ! !611 ! !612 +--------------------------------------+613 614 Example two - Phone camera615 616 It is more handy to go and swim with sharks with only your mobile phone617 with you and take pictures with the camera that is installed on the back618 side of the device, facing away from the user. The captured images are meant619 to be displayed in portrait mode (height > width) to match the device screen620 orientation and the device usage orientation used when taking the picture.621 622 The camera sensor is typically mounted with its pixel array longer side623 aligned to the device longer side, upside-down mounted to compensate for624 the lens optical inversion effect.625 626 The images once captured to memory will be rotated and the value of the627 V4L2_CID_CAMERA_SENSOR_ROTATION will report a 90 degree rotation. ::628 629 630 +-------------------------------------+631 | _ _ |632 | \ / |633 | | | |634 | | | |635 | | > |636 | < | |637 | | | |638 | . |639 | V |640 +-------------------------------------+641 642 A correction of 90 degrees in counter-clockwise direction has to be643 applied to correctly display the image in portrait mode on the device644 screen. ::645 646 +--------------------+647 | |648 | |649 | |650 | |651 | |652 | |653 | |\____)\___ |654 | ) _____ __`< |655 | |/ )/ |656 | |657 | |658 | |659 | |660 | |661 +--------------------+662 663 664.. [#f1]665 This control may be changed to a menu control in the future, if more666 options are required.667 668``V4L2_CID_HDR_SENSOR_MODE (menu)``669 Change the sensor HDR mode. A HDR picture is obtained by merging two670 captures of the same scene using two different exposure periods. HDR mode671 describes the way these two captures are merged in the sensor.672 673 As modes differ for each sensor, menu items are not standardized by this674 control and are left to the programmer.675