CaptureRequest

Whether black-level compensation is locked to its current values, or is free to vary.

When set to true (ON), the values used for black-level compensation will not change until the lock is set to false (OFF).

Since changes to certain capture parameters (such as exposure time) may require resetting of black level compensation, the camera device must report whether setting the black level lock was successful in the output result metadata.

For example, if a sequence of requests is as follows:

• Request 1: Exposure = 10ms, Black level lock = OFF
• Request 2: Exposure = 10ms, Black level lock = ON
• Request 3: Exposure = 10ms, Black level lock = ON
• Request 4: Exposure = 20ms, Black level lock = ON
• Request 5: Exposure = 20ms, Black level lock = ON
• Request 6: Exposure = 20ms, Black level lock = ON

And the exposure change in Request 4 requires the camera device to reset the black level offsets, then the output result metadata is expected to be:

• Result 1: Exposure = 10ms, Black level lock = OFF
• Result 2: Exposure = 10ms, Black level lock = ON
• Result 3: Exposure = 10ms, Black level lock = ON
• Result 4: Exposure = 20ms, Black level lock = OFF
• Result 5: Exposure = 20ms, Black level lock = ON
• Result 6: Exposure = 20ms, Black level lock = ON

This indicates to the application that on frame 4, black levels were reset due to exposure value changes, and pixel values may not be consistent across captures.

The camera device will maintain the lock to the extent possible, only overriding the lock to OFF when changes to other request parameters require a black level recalculation or reset.

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

Mode of operation for the chromatic aberration correction algorithm.

Chromatic (color) aberration is caused by the fact that different wavelengths of light can not focus on the same point after exiting from the lens. This metadata defines the high level control of chromatic aberration correction algorithm, which aims to minimize the chromatic artifacts that may occur along the object boundaries in an image.

FAST/HIGH_QUALITY both mean that camera device determined aberration correction will be applied. HIGH_QUALITY mode indicates that the camera device will use the highest-quality aberration correction algorithms, even if it slows down capture rate. FAST means the camera device will not slow down capture rate when applying aberration correction.

LEGACY devices will always be in FAST mode.

Possible values:

• OFF
• FAST
• HIGH_QUALITY

Available values for this device:
android.colorCorrection.availableAberrationModes

This key is available on all devices.

Gains applying to Bayer raw color channels for white-balance.

These per-channel gains are either set by the camera device when the request android.colorCorrection.mode is not TRANSFORM_MATRIX, or directly by the application in the request when the android.colorCorrection.mode is TRANSFORM_MATRIX.

The gains in the result metadata are the gains actually applied by the camera device to the current frame.

Units: Unitless gain factors

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

The mode control selects how the image data is converted from the sensor's native color into linear sRGB color.

When auto-white balance (AWB) is enabled with android.control.awbMode, this control is overridden by the AWB routine. When AWB is disabled, the application controls how the color mapping is performed.

We define the expected processing pipeline below. For consistency across devices, this is always the case with TRANSFORM_MATRIX.

When either FULL or HIGH_QUALITY is used, the camera device may do additional processing but android.colorCorrection.gains and android.colorCorrection.transform will still be provided by the camera device (in the results) and be roughly correct.

Switching to TRANSFORM_MATRIX and using the data provided from FAST or HIGH_QUALITY will yield a picture with the same white point as what was produced by the camera device in the earlier frame.

The expected processing pipeline is as follows:

The white balance is encoded by two values, a 4-channel white-balance gain vector (applied in the Bayer domain), and a 3x3 color transform matrix (applied after demosaic).

The 4-channel white-balance gains are defined as:

android.colorCorrection.gains = [ R G_even G_odd B ]
 

where G_even is the gain for green pixels on even rows of the output, and G_odd is the gain for green pixels on the odd rows. These may be identical for a given camera device implementation; if the camera device does not support a separate gain for even/odd green channels, it will use the G_even value, and write G_odd equal to G_even in the output result metadata.

The matrices for color transforms are defined as a 9-entry vector:

android.colorCorrection.transform = [ I0 I1 I2 I3 I4 I5 I6 I7 I8 ]
 

which define a transform from input sensor colors, P_in = [ r g b ], to output linear sRGB, P_out = [ r' g' b' ],

with colors as follows:

r' = I0r + I1g + I2b
 g' = I3r + I4g + I5b
 b' = I6r + I7g + I8b
 

Both the input and output value ranges must match. Overflow/underflow values are clipped to fit within the range.

Possible values:

• TRANSFORM_MATRIX
• FAST
• HIGH_QUALITY

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

A color transform matrix to use to transform from sensor RGB color space to output linear sRGB color space.

This matrix is either set by the camera device when the request android.colorCorrection.mode is not TRANSFORM_MATRIX, or directly by the application in the request when the android.colorCorrection.mode is TRANSFORM_MATRIX.

In the latter case, the camera device may round the matrix to account for precision issues; the final rounded matrix should be reported back in this matrix result metadata. The transform should keep the magnitude of the output color values within [0, 1.0] (assuming input color values is within the normalized range [0, 1.0]), or clipping may occur.

Units: Unitless scale factors

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

The desired setting for the camera device's auto-exposure algorithm's antibanding compensation.

Some kinds of lighting fixtures, such as some fluorescent lights, flicker at the rate of the power supply frequency (60Hz or 50Hz, depending on country). While this is typically not noticeable to a person, it can be visible to a camera device. If a camera sets its exposure time to the wrong value, the flicker may become visible in the viewfinder as flicker or in a final captured image, as a set of variable-brightness bands across the image.

Therefore, the auto-exposure routines of camera devices include antibanding routines that ensure that the chosen exposure value will not cause such banding. The choice of exposure time depends on the rate of flicker, which the camera device can detect automatically, or the expected rate can be selected by the application using this control.

A given camera device may not support all of the possible options for the antibanding mode. The android.control.aeAvailableAntibandingModes key contains the available modes for a given camera device.

AUTO mode is the default if it is available on given camera device. When AUTO mode is not available, the default will be either 50HZ or 60HZ, and both 50HZ and 60HZ will be available.

If manual exposure control is enabled (by setting android.control.aeMode or android.control.mode to OFF), then this setting has no effect, and the application must ensure it selects exposure times that do not cause banding issues. The android.statistics.sceneFlicker key can assist the application in this.

Possible values:

• OFF
• 50HZ
• 60HZ
• AUTO

Available values for this device:

android.control.aeAvailableAntibandingModes

This key is available on all devices.

Adjustment to auto-exposure (AE) target image brightness.

The adjustment is measured as a count of steps, with the step size defined by android.control.aeCompensationStep and the allowed range by android.control.aeCompensationRange.

For example, if the exposure value (EV) step is 0.333, '6' will mean an exposure compensation of +2 EV; -3 will mean an exposure compensation of -1 EV. One EV represents a doubling of image brightness. Note that this control will only be effective if android.control.aeMode != OFF. This control will take effect even when android.control.aeLock == true.

In the event of exposure compensation value being changed, camera device may take several frames to reach the newly requested exposure target. During that time, android.control.aeState field will be in the SEARCHING state. Once the new exposure target is reached, android.control.aeState will change from SEARCHING to either CONVERGED, LOCKED (if AE lock is enabled), or FLASH_REQUIRED (if the scene is too dark for still capture).

Units: Compensation steps

Range of valid values:
android.control.aeCompensationRange

This key is available on all devices.

Whether auto-exposure (AE) is currently locked to its latest calculated values.

When set to true (ON), the AE algorithm is locked to its latest parameters, and will not change exposure settings until the lock is set to false (OFF).

Note that even when AE is locked, the flash may be fired if the android.control.aeMode is ON_AUTO_FLASH / ON_ALWAYS_FLASH / ON_AUTO_FLASH_REDEYE.

When android.control.aeExposureCompensation is changed, even if the AE lock is ON, the camera device will still adjust its exposure value.

If AE precapture is triggered (see android.control.aePrecaptureTrigger) when AE is already locked, the camera device will not change the exposure time (android.sensor.exposureTime) and sensitivity (android.sensor.sensitivity) parameters. The flash may be fired if the android.control.aeMode is ON_AUTO_FLASH/ON_AUTO_FLASH_REDEYE and the scene is too dark. If the android.control.aeMode is ON_ALWAYS_FLASH, the scene may become overexposed.

Since the camera device has a pipeline of in-flight requests, the settings that get locked do not necessarily correspond to the settings that were present in the latest capture result received from the camera device, since additional captures and AE updates may have occurred even before the result was sent out. If an application is switching between automatic and manual control and wishes to eliminate any flicker during the switch, the following procedure is recommended:

1. Starting in auto-AE mode:
2. Lock AE
3. Wait for the first result to be output that has the AE locked
4. Copy exposure settings from that result into a request, set the request to manual AE
5. Submit the capture request, proceed to run manual AE as desired.

See android.control.aeState for AE lock related state transition details.

This key is available on all devices.

The desired mode for the camera device's auto-exposure routine.

This control is only effective if android.control.mode is AUTO.

When set to any of the ON modes, the camera device's auto-exposure routine is enabled, overriding the application's selected exposure time, sensor sensitivity, and frame duration (android.sensor.exposureTime, android.sensor.sensitivity, and android.sensor.frameDuration). If one of the FLASH modes is selected, the camera device's flash unit controls are also overridden.

The FLASH modes are only available if the camera device has a flash unit (android.flash.info.available is true).

If flash TORCH mode is desired, this field must be set to ON or OFF, and android.flash.mode set to TORCH.

When set to any of the ON modes, the values chosen by the camera device auto-exposure routine for the overridden fields for a given capture will be available in its CaptureResult.

Possible values:

• OFF
• ON
• ON_AUTO_FLASH
• ON_ALWAYS_FLASH
• ON_AUTO_FLASH_REDEYE

Available values for this device:
android.control.aeAvailableModes

This key is available on all devices.

Whether the camera device will trigger a precapture metering sequence when it processes this request.

This entry is normally set to IDLE, or is not included at all in the request settings. When included and set to START, the camera device will trigger the auto-exposure (AE) precapture metering sequence.

The precapture sequence should be triggered before starting a high-quality still capture for final metering decisions to be made, and for firing pre-capture flash pulses to estimate scene brightness and required final capture flash power, when the flash is enabled.

Normally, this entry should be set to START for only a single request, and the application should wait until the sequence completes before starting a new one.

When a precapture metering sequence is finished, the camera device may lock the auto-exposure routine internally to be able to accurately expose the subsequent still capture image (android.control.captureIntent == STILL_CAPTURE). For this case, the AE may not resume normal scan if no subsequent still capture is submitted. To ensure that the AE routine restarts normal scan, the application should submit a request with android.control.aeLock == true, followed by a request with android.control.aeLock == false, if the application decides not to submit a still capture request after the precapture sequence completes.

The exact effect of auto-exposure (AE) precapture trigger depends on the current AE mode and state; see android.control.aeState for AE precapture state transition details.

On LEGACY-level devices, the precapture trigger is not supported; capturing a high-resolution JPEG image will automatically trigger a precapture sequence before the high-resolution capture, including potentially firing a pre-capture flash.

Possible values:

• IDLE
• START

Optional - This value may be null on some devices.

Limited capability - Present on all camera devices that report being at least HARDWARE_LEVEL_LIMITED devices in the android.info.supportedHardwareLevel key

List of metering areas to use for auto-exposure adjustment.

Not available if android.control.maxRegionsAe is 0. Otherwise will always be present.

The maximum number of regions supported by the device is determined by the value of android.control.maxRegionsAe.

The coordinate system is based on the active pixel array, with (0,0) being the top-left pixel in the active pixel array, and (android.sensor.info.activeArraySize.width - 1, android.sensor.info.activeArraySize.height - 1) being the bottom-right pixel in the active pixel array.

The weight must be within [0, 1000], and represents a weight for every pixel in the area. This means that a large metering area with the same weight as a smaller area will have more effect in the metering result. Metering areas can partially overlap and the camera device will add the weights in the overlap region.

The weights are relative to weights of other exposure metering regions, so if only one region is used, all non-zero weights will have the same effect. A region with 0 weight is ignored.

If all regions have 0 weight, then no specific metering area needs to be used by the camera device.

If the metering region is outside the used android.scaler.cropRegion returned in capture result metadata, the camera device will ignore the sections outside the crop region and output only the intersection rectangle as the metering region in the result metadata. If the region is entirely outside the crop region, it will be ignored and not reported in the result metadata.

Units: Pixel coordinates within android.sensor.info.activeArraySize

Range of valid values:
Coordinates must be between [(0,0), (width, height)) of android.sensor.info.activeArraySize

Optional - This value may be null on some devices.

Range over which the auto-exposure routine can adjust the capture frame rate to maintain good exposure.

Only constrains auto-exposure (AE) algorithm, not manual control of android.sensor.exposureTime and android.sensor.frameDuration.

Units: Frames per second (FPS)

Range of valid values:
Any of the entries in android.control.aeAvailableTargetFpsRanges

This key is available on all devices.

Whether auto-focus (AF) is currently enabled, and what mode it is set to.

Only effective if android.control.mode = AUTO and the lens is not fixed focus (i.e. android.lens.info.minimumFocusDistance > 0). Also note that when android.control.aeMode is OFF, the behavior of AF is device dependent. It is recommended to lock AF by using android.control.afTrigger before setting android.control.aeMode to OFF, or set AF mode to OFF when AE is OFF.

If the lens is controlled by the camera device auto-focus algorithm, the camera device will report the current AF status in android.control.afState in result metadata.

Possible values:

• OFF
• AUTO
• MACRO
• CONTINUOUS_VIDEO
• CONTINUOUS_PICTURE
• EDOF

Available values for this device:
android.control.afAvailableModes

This key is available on all devices.

List of metering areas to use for auto-focus.

Not available if android.control.maxRegionsAf is 0. Otherwise will always be present.

The maximum number of focus areas supported by the device is determined by the value of android.control.maxRegionsAf.

The coordinate system is based on the active pixel array, with (0,0) being the top-left pixel in the active pixel array, and (android.sensor.info.activeArraySize.width - 1, android.sensor.info.activeArraySize.height - 1) being the bottom-right pixel in the active pixel array.

The weight must be within [0, 1000], and represents a weight for every pixel in the area. This means that a large metering area with the same weight as a smaller area will have more effect in the metering result. Metering areas can partially overlap and the camera device will add the weights in the overlap region.

The weights are relative to weights of other metering regions, so if only one region is used, all non-zero weights will have the same effect. A region with 0 weight is ignored.

If all regions have 0 weight, then no specific metering area needs to be used by the camera device.

If the metering region is outside the used android.scaler.cropRegion returned in capture result metadata, the camera device will ignore the sections outside the crop region and output only the intersection rectangle as the metering region in the result metadata. If the region is entirely outside the crop region, it will be ignored and not reported in the result metadata.

Units: Pixel coordinates within android.sensor.info.activeArraySize

Range of valid values:
Coordinates must be between [(0,0), (width, height)) of android.sensor.info.activeArraySize

Optional - This value may be null on some devices.

Whether the camera device will trigger autofocus for this request.

This entry is normally set to IDLE, or is not included at all in the request settings.

When included and set to START, the camera device will trigger the autofocus algorithm. If autofocus is disabled, this trigger has no effect.

When set to CANCEL, the camera device will cancel any active trigger, and return to its initial AF state.

Generally, applications should set this entry to START or CANCEL for only a single capture, and then return it to IDLE (or not set at all). Specifying START for multiple captures in a row means restarting the AF operation over and over again.

See android.control.afState for what the trigger means for each AF mode.

Possible values:

• IDLE
• START
• CANCEL

This key is available on all devices.

Whether auto-white balance (AWB) is currently locked to its latest calculated values.

When set to true (ON), the AWB algorithm is locked to its latest parameters, and will not change color balance settings until the lock is set to false (OFF).

Since the camera device has a pipeline of in-flight requests, the settings that get locked do not necessarily correspond to the settings that were present in the latest capture result received from the camera device, since additional captures and AWB updates may have occurred even before the result was sent out. If an application is switching between automatic and manual control and wishes to eliminate any flicker during the switch, the following procedure is recommended:

1. Starting in auto-AWB mode:
2. Lock AWB
3. Wait for the first result to be output that has the AWB locked
4. Copy AWB settings from that result into a request, set the request to manual AWB
5. Submit the capture request, proceed to run manual AWB as desired.

Note that AWB lock is only meaningful when android.control.awbMode is in the AUTO mode; in other modes, AWB is already fixed to a specific setting.

Some LEGACY devices may not support ON; the value is then overridden to OFF.

This key is available on all devices.

Whether auto-white balance (AWB) is currently setting the color transform fields, and what its illumination target is.

This control is only effective if android.control.mode is AUTO.

When set to the ON mode, the camera device's auto-white balance routine is enabled, overriding the application's selected android.colorCorrection.transform, android.colorCorrection.gains and android.colorCorrection.mode. Note that when android.control.aeMode is OFF, the behavior of AWB is device dependent. It is recommened to also set AWB mode to OFF or lock AWB by using android.control.awbLock before setting AE mode to OFF.

When set to the OFF mode, the camera device's auto-white balance routine is disabled. The application manually controls the white balance by android.colorCorrection.transform, android.colorCorrection.gains and android.colorCorrection.mode.

When set to any other modes, the camera device's auto-white balance routine is disabled. The camera device uses each particular illumination target for white balance adjustment. The application's values for android.colorCorrection.transform, android.colorCorrection.gains and android.colorCorrection.mode are ignored.

Possible values:

• OFF
• AUTO
• INCANDESCENT
• FLUORESCENT
• WARM_FLUORESCENT
• DAYLIGHT
• CLOUDY_DAYLIGHT
• TWILIGHT
• SHADE

Available values for this device:
android.control.awbAvailableModes

This key is available on all devices.

List of metering areas to use for auto-white-balance illuminant estimation.

Not available if android.control.maxRegionsAwb is 0. Otherwise will always be present.

The maximum number of regions supported by the device is determined by the value of android.control.maxRegionsAwb.

The coordinate system is based on the active pixel array, with (0,0) being the top-left pixel in the active pixel array, and (android.sensor.info.activeArraySize.width - 1, android.sensor.info.activeArraySize.height - 1) being the bottom-right pixel in the active pixel array.

The weight must range from 0 to 1000, and represents a weight for every pixel in the area. This means that a large metering area with the same weight as a smaller area will have more effect in the metering result. Metering areas can partially overlap and the camera device will add the weights in the overlap region.

The weights are relative to weights of other white balance metering regions, so if only one region is used, all non-zero weights will have the same effect. A region with 0 weight is ignored.

If all regions have 0 weight, then no specific metering area needs to be used by the camera device.

If the metering region is outside the used android.scaler.cropRegion returned in capture result metadata, the camera device will ignore the sections outside the crop region and output only the intersection rectangle as the metering region in the result metadata. If the region is entirely outside the crop region, it will be ignored and not reported in the result metadata.

Units: Pixel coordinates within android.sensor.info.activeArraySize

Range of valid values:
Coordinates must be between [(0,0), (width, height)) of android.sensor.info.activeArraySize

Optional - This value may be null on some devices.

Information to the camera device 3A (auto-exposure, auto-focus, auto-white balance) routines about the purpose of this capture, to help the camera device to decide optimal 3A strategy.

This control (except for MANUAL) is only effective if android.control.mode != OFF and any 3A routine is active.

ZERO_SHUTTER_LAG will be supported if android.request.availableCapabilities contains ZSL. MANUAL will be supported if android.request.availableCapabilities contains MANUAL_SENSOR. Other intent values are always supported.

Possible values:

• CUSTOM
• PREVIEW
• STILL_CAPTURE
• VIDEO_RECORD
• VIDEO_SNAPSHOT
• ZERO_SHUTTER_LAG
• MANUAL

This key is available on all devices.

A special color effect to apply.

When this mode is set, a color effect will be applied to images produced by the camera device. The interpretation and implementation of these color effects is left to the implementor of the camera device, and should not be depended on to be consistent (or present) across all devices.

Possible values:

• OFF
• MONO
• NEGATIVE
• SOLARIZE
• SEPIA
• POSTERIZE
• WHITEBOARD
• BLACKBOARD
• AQUA

Available values for this device:
android.control.availableEffects

This key is available on all devices.

Overall mode of 3A (auto-exposure, auto-white-balance, auto-focus) control routines.

This is a top-level 3A control switch. When set to OFF, all 3A control by the camera device is disabled. The application must set the fields for capture parameters itself.

When set to AUTO, the individual algorithm controls in android.control.* are in effect, such as android.control.afMode.

When set to USE_SCENE_MODE, the individual controls in android.control.* are mostly disabled, and the camera device implements one of the scene mode settings (such as ACTION, SUNSET, or PARTY) as it wishes. The camera device scene mode 3A settings are provided by android.control.sceneModeOverrides.

When set to OFF_KEEP_STATE, it is similar to OFF mode, the only difference is that this frame will not be used by camera device background 3A statistics update, as if this frame is never captured. This mode can be used in the scenario where the application doesn't want a 3A manual control capture to affect the subsequent auto 3A capture results.

LEGACY mode devices will only support AUTO and USE_SCENE_MODE modes. LIMITED mode devices will only support OFF and OFF_KEEP_STATE if they support the MANUAL_SENSOR and MANUAL_POST_PROCSESING capabilities. FULL mode devices will always support OFF and OFF_KEEP_STATE.

Possible values:

• OFF
• AUTO
• USE_SCENE_MODE
• OFF_KEEP_STATE

This key is available on all devices.

Control for which scene mode is currently active.

Scene modes are custom camera modes optimized for a certain set of conditions and capture settings.

This is the mode that that is active when android.control.mode == USE_SCENE_MODE. Aside from FACE_PRIORITY, these modes will disable android.control.aeMode, android.control.awbMode, and android.control.afMode while in use.

The interpretation and implementation of these scene modes is left to the implementor of the camera device. Their behavior will not be consistent across all devices, and any given device may only implement a subset of these modes.

Possible values:

• DISABLED
• FACE_PRIORITY
• ACTION
• PORTRAIT
• LANDSCAPE
• NIGHT
• NIGHT_PORTRAIT
• THEATRE
• BEACH
• SNOW
• SUNSET
• STEADYPHOTO
• FIREWORKS
• SPORTS
• PARTY
• CANDLELIGHT
• BARCODE
• HIGH_SPEED_VIDEO
• HDR

Available values for this device:
android.control.availableSceneModes

This key is available on all devices.

Whether video stabilization is active.

Video stabilization automatically translates and scales images from the camera in order to stabilize motion between consecutive frames.

If enabled, video stabilization can modify the android.scaler.cropRegion to keep the video stream stabilized.

Switching between different video stabilization modes may take several frames to initialize, the camera device will report the current mode in capture result metadata. For example, When "ON" mode is requested, the video stabilization modes in the first several capture results may still be "OFF", and it will become "ON" when the initialization is done.

If a camera device supports both this mode and OIS (android.lens.opticalStabilizationMode), turning both modes on may produce undesirable interaction, so it is recommended not to enable both at the same time.

Possible values:

• OFF
• ON

This key is available on all devices.

Operation mode for edge enhancement.

Edge enhancement improves sharpness and details in the captured image. OFF means no enhancement will be applied by the camera device.

FAST/HIGH_QUALITY both mean camera device determined enhancement will be applied. HIGH_QUALITY mode indicates that the camera device will use the highest-quality enhancement algorithms, even if it slows down capture rate. FAST means the camera device will not slow down capture rate when applying edge enhancement.

Possible values:

• OFF
• FAST
• HIGH_QUALITY

Available values for this device:
android.edge.availableEdgeModes

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

The desired mode for for the camera device's flash control.

This control is only effective when flash unit is available (android.flash.info.available == true).

When this control is used, the android.control.aeMode must be set to ON or OFF. Otherwise, the camera device auto-exposure related flash control (ON_AUTO_FLASH, ON_ALWAYS_FLASH, or ON_AUTO_FLASH_REDEYE) will override this control.

When set to OFF, the camera device will not fire flash for this capture.

When set to SINGLE, the camera device will fire flash regardless of the camera device's auto-exposure routine's result. When used in still capture case, this control should be used along with auto-exposure (AE) precapture metering sequence (android.control.aePrecaptureTrigger), otherwise, the image may be incorrectly exposed.

When set to TORCH, the flash will be on continuously. This mode can be used for use cases such as preview, auto-focus assist, still capture, or video recording.

The flash status will be reported by android.flash.state in the capture result metadata.

Possible values:

• OFF
• SINGLE
• TORCH

This key is available on all devices.

Operational mode for hot pixel correction.

Hotpixel correction interpolates out, or otherwise removes, pixels that do not accurately measure the incoming light (i.e. pixels that are stuck at an arbitrary value or are oversensitive).

Possible values:

• OFF
• FAST
• HIGH_QUALITY

Available values for this device:
android.hotPixel.availableHotPixelModes

Optional - This value may be null on some devices.

A location object to use when generating image GPS metadata.

Setting a location object in a request will include the GPS coordinates of the location into any JPEG images captured based on the request. These coordinates can then be viewed by anyone who receives the JPEG image.

This key is available on all devices.

The orientation for a JPEG image.

The clockwise rotation angle in degrees, relative to the orientation to the camera, that the JPEG picture needs to be rotated by, to be viewed upright.

Camera devices may either encode this value into the JPEG EXIF header, or rotate the image data to match this orientation.

Note that this orientation is relative to the orientation of the camera sensor, given by android.sensor.orientation.

To translate from the device orientation given by the Android sensor APIs, the following sample code may be used:

private int getJpegOrientation(CameraCharacteristics c, int deviceOrientation) {
     if (deviceOrientation == android.view.OrientationEventListener.ORIENTATION_UNKNOWN) return 0;
     int sensorOrientation = c.get(CameraCharacteristics.SENSOR_ORIENTATION);

     // Round device orientation to a multiple of 90
     deviceOrientation = (deviceOrientation + 45) / 90 * 90;

     // Reverse device orientation for front-facing cameras
     boolean facingFront = c.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_FRONT;
     if (facingFront) deviceOrientation = -deviceOrientation;

     // Calculate desired JPEG orientation relative to camera orientation to make
     // the image upright relative to the device orientation
     int jpegOrientation = (sensorOrientation + deviceOrientation + 360) % 360;

     return jpegOrientation;
 }
 

Units: Degrees in multiples of 90

Range of valid values:
0, 90, 180, 270

This key is available on all devices.

Compression quality of the final JPEG image.

85-95 is typical usage range.

Range of valid values:
1-100; larger is higher quality

This key is available on all devices.

Compression quality of JPEG thumbnail.

Range of valid values:
1-100; larger is higher quality

This key is available on all devices.

Resolution of embedded JPEG thumbnail.

When set to (0, 0) value, the JPEG EXIF will not contain thumbnail, but the captured JPEG will still be a valid image.

For best results, when issuing a request for a JPEG image, the thumbnail size selected should have the same aspect ratio as the main JPEG output.

If the thumbnail image aspect ratio differs from the JPEG primary image aspect ratio, the camera device creates the thumbnail by cropping it from the primary image. For example, if the primary image has 4:3 aspect ratio, the thumbnail image has 16:9 aspect ratio, the primary image will be cropped vertically (letterbox) to generate the thumbnail image. The thumbnail image will always have a smaller Field Of View (FOV) than the primary image when aspect ratios differ.

Range of valid values:
android.jpeg.availableThumbnailSizes

This key is available on all devices.

The desired lens aperture size, as a ratio of lens focal length to the effective aperture diameter.

Setting this value is only supported on the camera devices that have a variable aperture lens.

When this is supported and android.control.aeMode is OFF, this can be set along with android.sensor.exposureTime, android.sensor.sensitivity, and android.sensor.frameDuration to achieve manual exposure control.

The requested aperture value may take several frames to reach the requested value; the camera device will report the current (intermediate) aperture size in capture result metadata while the aperture is changing. While the aperture is still changing, android.lens.state will be set to MOVING.

When this is supported and android.control.aeMode is one of the ON modes, this will be overridden by the camera device auto-exposure algorithm, the overridden values are then provided back to the user in the corresponding result.

Units: The f-number (f/N)

Range of valid values:
android.lens.info.availableApertures

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

The desired setting for the lens neutral density filter(s).

This control will not be supported on most camera devices.

Lens filters are typically used to lower the amount of light the sensor is exposed to (measured in steps of EV). As used here, an EV step is the standard logarithmic representation, which are non-negative, and inversely proportional to the amount of light hitting the sensor. For example, setting this to 0 would result in no reduction of the incoming light, and setting this to 2 would mean that the filter is set to reduce incoming light by two stops (allowing 1/4 of the prior amount of light to the sensor).

It may take several frames before the lens filter density changes to the requested value. While the filter density is still changing, android.lens.state will be set to MOVING.

Units: Exposure Value (EV)

Range of valid values:
android.lens.info.availableFilterDensities

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

The desired lens focal length; used for optical zoom.

This setting controls the physical focal length of the camera device's lens. Changing the focal length changes the field of view of the camera device, and is usually used for optical zoom.

Like android.lens.focusDistance and android.lens.aperture, this setting won't be applied instantaneously, and it may take several frames before the lens can change to the requested focal length. While the focal length is still changing, android.lens.state will be set to MOVING.

Optical zoom will not be supported on most devices.

Units: Millimeters

Range of valid values:
android.lens.info.availableFocalLengths

This key is available on all devices.

Desired distance to plane of sharpest focus, measured from frontmost surface of the lens.

This control can be used for setting manual focus, on devices that support the MANUAL_SENSOR capability and have a variable-focus lens (see android.lens.info.minimumFocusDistance).

A value of 0.0f means infinity focus. The value set will be clamped to [0.0f, android.lens.info.minimumFocusDistance].

Like android.lens.focalLength, this setting won't be applied instantaneously, and it may take several frames before the lens can move to the requested focus distance. While the lens is still moving, android.lens.state will be set to MOVING.

LEGACY devices support at most setting this to 0.0f for infinity focus.

Units: See android.lens.info.focusDistanceCalibration for details

Range of valid values:
>= 0

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

Sets whether the camera device uses optical image stabilization (OIS) when capturing images.

OIS is used to compensate for motion blur due to small movements of the camera during capture. Unlike digital image stabilization (android.control.videoStabilizationMode), OIS makes use of mechanical elements to stabilize the camera sensor, and thus allows for longer exposure times before camera shake becomes apparent.

Switching between different optical stabilization modes may take several frames to initialize, the camera device will report the current mode in capture result metadata. For example, When "ON" mode is requested, the optical stabilization modes in the first several capture results may still be "OFF", and it will become "ON" when the initialization is done.

If a camera device supports both OIS and digital image stabilization (android.control.videoStabilizationMode), turning both modes on may produce undesirable interaction, so it is recommended not to enable both at the same time.

Not all devices will support OIS; see android.lens.info.availableOpticalStabilization for available controls.

Possible values:

• OFF
• ON

Available values for this device:
android.lens.info.availableOpticalStabilization

Optional - This value may be null on some devices.

Limited capability - Present on all camera devices that report being at least HARDWARE_LEVEL_LIMITED devices in the android.info.supportedHardwareLevel key

Mode of operation for the noise reduction algorithm.

The noise reduction algorithm attempts to improve image quality by removing excessive noise added by the capture process, especially in dark conditions. OFF means no noise reduction will be applied by the camera device.

FAST/HIGH_QUALITY both mean camera device determined noise filtering will be applied. HIGH_QUALITY mode indicates that the camera device will use the highest-quality noise filtering algorithms, even if it slows down capture rate. FAST means the camera device will not slow down capture rate when applying noise filtering.

Possible values:

• OFF
• FAST
• HIGH_QUALITY

Available values for this device:
android.noiseReduction.availableNoiseReductionModes

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

The desired region of the sensor to read out for this capture.

This control can be used to implement digital zoom.

The crop region coordinate system is based off android.sensor.info.activeArraySize, with (0, 0) being the top-left corner of the sensor active array.

Output streams use this rectangle to produce their output, cropping to a smaller region if necessary to maintain the stream's aspect ratio, then scaling the sensor input to match the output's configured resolution.

The crop region is applied after the RAW to other color space (e.g. YUV) conversion. Since raw streams (e.g. RAW16) don't have the conversion stage, they are not croppable. The crop region will be ignored by raw streams.

For non-raw streams, any additional per-stream cropping will be done to maximize the final pixel area of the stream.

For example, if the crop region is set to a 4:3 aspect ratio, then 4:3 streams will use the exact crop region. 16:9 streams will further crop vertically (letterbox).

Conversely, if the crop region is set to a 16:9, then 4:3 outputs will crop horizontally (pillarbox), and 16:9 streams will match exactly. These additional crops will be centered within the crop region.

The width and height of the crop region cannot be set to be smaller than floor( activeArraySize.width / android.scaler.availableMaxDigitalZoom ) and floor( activeArraySize.height / android.scaler.availableMaxDigitalZoom ), respectively.

The camera device may adjust the crop region to account for rounding and other hardware requirements; the final crop region used will be included in the output capture result.

Units: Pixel coordinates relative to android.sensor.info.activeArraySize

This key is available on all devices.

Duration each pixel is exposed to light.

If the sensor can't expose this exact duration, it will shorten the duration exposed to the nearest possible value (rather than expose longer). The final exposure time used will be available in the output capture result.

This control is only effective if android.control.aeMode or android.control.mode is set to OFF; otherwise the auto-exposure algorithm will override this value.

Units: Nanoseconds

Range of valid values:
android.sensor.info.exposureTimeRange

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

Duration from start of frame exposure to start of next frame exposure.

The maximum frame rate that can be supported by a camera subsystem is a function of many factors:

• Requested resolutions of output image streams
• Availability of binning / skipping modes on the imager
• The bandwidth of the imager interface
• The bandwidth of the various ISP processing blocks

Since these factors can vary greatly between different ISPs and sensors, the camera abstraction tries to represent the bandwidth restrictions with as simple a model as possible.

The model presented has the following characteristics:

• The image sensor is always configured to output the smallest resolution possible given the application's requested output stream sizes. The smallest resolution is defined as being at least as large as the largest requested output stream size; the camera pipeline must never digitally upsample sensor data when the crop region covers the whole sensor. In general, this means that if only small output stream resolutions are configured, the sensor can provide a higher frame rate.
• Since any request may use any or all the currently configured output streams, the sensor and ISP must be configured to support scaling a single capture to all the streams at the same time. This means the camera pipeline must be ready to produce the largest requested output size without any delay. Therefore, the overall frame rate of a given configured stream set is governed only by the largest requested stream resolution.
• Using more than one output stream in a request does not affect the frame duration.
• Certain format-streams may need to do additional background processing before data is consumed/produced by that stream. These processors can run concurrently to the rest of the camera pipeline, but cannot process more than 1 capture at a time.

The necessary information for the application, given the model above, is provided via the android.scaler.streamConfigurationMap field using StreamConfigurationMap#getOutputMinFrameDuration(int, Size). These are used to determine the maximum frame rate / minimum frame duration that is possible for a given stream configuration.

Specifically, the application can use the following rules to determine the minimum frame duration it can request from the camera device:

1. Let the set of currently configured input/output streams be called S.
2. Find the minimum frame durations for each stream in S, by looking it up in android.scaler.streamConfigurationMap using StreamConfigurationMap#getOutputMinFrameDuration(int, Size) (with its respective size/format). Let this set of frame durations be called F.
3. For any given request R, the minimum frame duration allowed for R is the maximum out of all values in F. Let the streams used in R be called S_r.

If none of the streams in S_r have a stall time (listed in StreamConfigurationMap#getOutputStallDuration(int,Size) using its respective size/format), then the frame duration in F determines the steady state frame rate that the application will get if it uses R as a repeating request. Let this special kind of request be called Rsimple.

A repeating request Rsimple can be occasionally interleaved by a single capture of a new request Rstall (which has at least one in-use stream with a non-0 stall time) and if Rstall has the same minimum frame duration this will not cause a frame rate loss if all buffers from the previous Rstall have already been delivered.

For more details about stalling, see StreamConfigurationMap#getOutputStallDuration(int,Size).

This control is only effective if android.control.aeMode or android.control.mode is set to OFF; otherwise the auto-exposure algorithm will override this value.

Units: Nanoseconds

Range of valid values:
See android.sensor.info.maxFrameDuration, android.scaler.streamConfigurationMap. The duration is capped to max(duration, exposureTime + overhead).

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

The amount of gain applied to sensor data before processing.

The sensitivity is the standard ISO sensitivity value, as defined in ISO 12232:2006.

The sensitivity must be within android.sensor.info.sensitivityRange, and if if it less than android.sensor.maxAnalogSensitivity, the camera device is guaranteed to use only analog amplification for applying the gain.

If the camera device cannot apply the exact sensitivity requested, it will reduce the gain to the nearest supported value. The final sensitivity used will be available in the output capture result.

Units: ISO arithmetic units

Range of valid values:
android.sensor.info.sensitivityRange

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

A pixel [R, G_even, G_odd, B] that supplies the test pattern when android.sensor.testPatternMode is SOLID_COLOR.

Each color channel is treated as an unsigned 32-bit integer. The camera device then uses the most significant X bits that correspond to how many bits are in its Bayer raw sensor output.

For example, a sensor with RAW10 Bayer output would use the 10 most significant bits from each color channel.

Optional - This value may be null on some devices.

When enabled, the sensor sends a test pattern instead of doing a real exposure from the camera.

When a test pattern is enabled, all manual sensor controls specified by android.sensor.* will be ignored. All other controls should work as normal.

For example, if manual flash is enabled, flash firing should still occur (and that the test pattern remain unmodified, since the flash would not actually affect it).

Defaults to OFF.

Possible values:

• OFF
• SOLID_COLOR
• COLOR_BARS
• COLOR_BARS_FADE_TO_GRAY
• PN9
• CUSTOM1

Available values for this device:
android.sensor.availableTestPatternModes

Optional - This value may be null on some devices.

Quality of lens shading correction applied to the image data.

When set to OFF mode, no lens shading correction will be applied by the camera device, and an identity lens shading map data will be provided if android.statistics.lensShadingMapMode == ON. For example, for lens shading map with size of [ 4, 3 ], the output android.statistics.lensShadingCorrectionMap for this case will be an identity map shown below:

[ 1.0, 1.0, 1.0, 1.0,  1.0, 1.0, 1.0, 1.0,
  1.0, 1.0, 1.0, 1.0,  1.0, 1.0, 1.0, 1.0,
  1.0, 1.0, 1.0, 1.0,  1.0, 1.0, 1.0, 1.0,
  1.0, 1.0, 1.0, 1.0,  1.0, 1.0, 1.0, 1.0,
  1.0, 1.0, 1.0, 1.0,  1.0, 1.0, 1.0, 1.0,
  1.0, 1.0, 1.0, 1.0,  1.0, 1.0, 1.0, 1.0 ]
 

When set to other modes, lens shading correction will be applied by the camera device. Applications can request lens shading map data by setting android.statistics.lensShadingMapMode to ON, and then the camera device will provide lens shading map data in android.statistics.lensShadingCorrectionMap; the returned shading map data will be the one applied by the camera device for this capture request.

The shading map data may depend on the auto-exposure (AE) and AWB statistics, therefore the reliability of the map data may be affected by the AE and AWB algorithms. When AE and AWB are in AUTO modes(android.control.aeMode != OFF and android.control.awbMode != OFF), to get best results, it is recommended that the applications wait for the AE and AWB to be converged before using the returned shading map data.

Possible values:

• OFF
• FAST
• HIGH_QUALITY

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

Operating mode for the face detector unit.

Whether face detection is enabled, and whether it should output just the basic fields or the full set of fields.

Possible values:

• OFF
• SIMPLE
• FULL

Available values for this device:
android.statistics.info.availableFaceDetectModes

This key is available on all devices.

Operating mode for hot pixel map generation.

If set to true, a hot pixel map is returned in android.statistics.hotPixelMap. If set to false, no hot pixel map will be returned.

Range of valid values:
android.statistics.info.availableHotPixelMapModes

Optional - This value may be null on some devices.

Whether the camera device will output the lens shading map in output result metadata.

When set to ON, android.statistics.lensShadingMap will be provided in the output result metadata.

ON is always supported on devices with the RAW capability.

Possible values:

• OFF
• ON

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

Tonemapping / contrast / gamma curve to use when android.tonemap.mode is CONTRAST_CURVE.

The tonemapCurve consist of three curves for each of red, green, and blue channels respectively. The following example uses the red channel as an example. The same logic applies to green and blue channel. Each channel's curve is defined by an array of control points:

curveRed =
   [ P0(in, out), P1(in, out), P2(in, out), P3(in, out), ..., PN(in, out) ]
 2 <= N <= android.tonemap.maxCurvePoints

These are sorted in order of increasing Pin; it is always guaranteed that input values 0.0 and 1.0 are included in the list to define a complete mapping. For input values between control points, the camera device must linearly interpolate between the control points.

Each curve can have an independent number of points, and the number of points can be less than max (that is, the request doesn't have to always provide a curve with number of points equivalent to android.tonemap.maxCurvePoints).

A few examples, and their corresponding graphical mappings; these only specify the red channel and the precision is limited to 4 digits, for conciseness.

Linear mapping:

curveRed = [ (0, 0), (1.0, 1.0) ]
 

Invert mapping:

curveRed = [ (0, 1.0), (1.0, 0) ]
 

Gamma 1/2.2 mapping, with 16 control points:

curveRed = [
   (0.0000, 0.0000), (0.0667, 0.2920), (0.1333, 0.4002), (0.2000, 0.4812),
   (0.2667, 0.5484), (0.3333, 0.6069), (0.4000, 0.6594), (0.4667, 0.7072),
   (0.5333, 0.7515), (0.6000, 0.7928), (0.6667, 0.8317), (0.7333, 0.8685),
   (0.8000, 0.9035), (0.8667, 0.9370), (0.9333, 0.9691), (1.0000, 1.0000) ]
 

Standard sRGB gamma mapping, per IEC 61966-2-1:1999, with 16 control points:

curveRed = [
   (0.0000, 0.0000), (0.0667, 0.2864), (0.1333, 0.4007), (0.2000, 0.4845),
   (0.2667, 0.5532), (0.3333, 0.6125), (0.4000, 0.6652), (0.4667, 0.7130),
   (0.5333, 0.7569), (0.6000, 0.7977), (0.6667, 0.8360), (0.7333, 0.8721),
   (0.8000, 0.9063), (0.8667, 0.9389), (0.9333, 0.9701), (1.0000, 1.0000) ]
 

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

High-level global contrast/gamma/tonemapping control.

When switching to an application-defined contrast curve by setting android.tonemap.mode to CONTRAST_CURVE, the curve is defined per-channel with a set of (in, out) points that specify the mapping from input high-bit-depth pixel value to the output low-bit-depth value. Since the actual pixel ranges of both input and output may change depending on the camera pipeline, the values are specified by normalized floating-point numbers.

More-complex color mapping operations such as 3D color look-up tables, selective chroma enhancement, or other non-linear color transforms will be disabled when android.tonemap.mode is CONTRAST_CURVE.

When using either FAST or HIGH_QUALITY, the camera device will emit its own tonemap curve in android.tonemap.curve. These values are always available, and as close as possible to the actually used nonlinear/nonglobal transforms.

If a request is sent with CONTRAST_CURVE with the camera device's provided curve in FAST or HIGH_QUALITY, the image's tonemap will be roughly the same.

Possible values:

• CONTRAST_CURVE
• FAST
• HIGH_QUALITY

Available values for this device:
android.tonemap.availableToneMapModes

Optional - This value may be null on some devices.

Full capability - Present on all camera devices that report being HARDWARE_LEVEL_FULL devices in the android.info.supportedHardwareLevel key

Describe the kinds of special objects contained in this Parcelable's marshalled representation.

Determine whether this CaptureRequest is equal to another CaptureRequest.

A request is considered equal to another is if it's set of key/values is equal, it's list of output surfaces is equal, and the user tag is equal.

Get a capture request field value.

The field definitions can be found in CaptureRequest.

Querying the value for the same key more than once will return a value which is equal to the previous queried value.

Returns a list of the keys contained in this map.

The list returned is not modifiable, so any attempts to modify it will throw a UnsupportedOperationException.

All values retrieved by a key from this list with #get are guaranteed to be non-null. Each key is only listed once in the list. The order of the keys is undefined.

Retrieve the tag for this request, if any.

This tag is not used for anything by the camera device, but can be used by an application to easily identify a CaptureRequest when it is returned by CaptureCallback.onCaptureCompleted

Returns an integer hash code for this object. By contract, any two objects for which equals(Object) returns true must return the same hash code value. This means that subclasses of Object usually override both methods or neither method.

Note that hash values must not change over time unless information used in equals comparisons also changes.

See Writing a correct hashCode method if you intend implementing your own hashCode method.

Flatten this object in to a Parcel.