libcamera: libcamera::controls Namespace Reference

libcamera v0.5.0 Supporting cameras in Linux since 2019 |

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libcamera::controls Namespace Reference

Namespace for libcamera controls. More...

## Namespaces
namespace | debug
| Namespace for debug controls.
namespace | draft
| Namespace for draft controls.
namespace | rpi
| Namespace for rpi controls.

## Enumerations
enum | AeStateEnum { AeStateIdle = 0 , AeStateSearching = 1 , AeStateConverged = 2 }
| Supported AeState values. More...
enum | AeMeteringModeEnum { MeteringCentreWeighted = 0 , MeteringSpot = 1 , MeteringMatrix = 2 , MeteringCustom = 3 }
| Supported AeMeteringMode values. More...
enum | AeConstraintModeEnum { ConstraintNormal = 0 , ConstraintHighlight = 1 , ConstraintShadows = 2 , ConstraintCustom = 3 }
| Supported AeConstraintMode values. More...
enum | AeExposureModeEnum { ExposureNormal = 0 , ExposureShort = 1 , ExposureLong = 2 , ExposureCustom = 3 }
| Supported AeExposureMode values. More...
enum | ExposureTimeModeEnum { ExposureTimeModeAuto = 0 , ExposureTimeModeManual = 1 }
| Supported ExposureTimeMode values. More...
enum | AnalogueGainModeEnum { AnalogueGainModeAuto = 0 , AnalogueGainModeManual = 1 }
| Supported AnalogueGainMode values. More...
enum | AeFlickerModeEnum { FlickerOff = 0 , FlickerManual = 1 , FlickerAuto = 2 }
| Supported AeFlickerMode values. More...
enum | AwbModeEnum { AwbAuto = 0 , AwbIncandescent = 1 , AwbTungsten = 2 , AwbFluorescent = 3 , AwbIndoor = 4 , AwbDaylight = 5 , AwbCloudy = 6 , AwbCustom = 7 }
| Supported AwbMode values. More...
enum | AfModeEnum { AfModeManual = 0 , AfModeAuto = 1 , AfModeContinuous = 2 }
| Supported AfMode values. More...
enum | AfRangeEnum { AfRangeNormal = 0 , AfRangeMacro = 1 , AfRangeFull = 2 }
| Supported AfRange values. More...
enum | AfSpeedEnum { AfSpeedNormal = 0 , AfSpeedFast = 1 }
| Supported AfSpeed values. More...
enum | AfMeteringEnum { AfMeteringAuto = 0 , AfMeteringWindows = 1 }
| Supported AfMetering values. More...
enum | AfTriggerEnum { AfTriggerStart = 0 , AfTriggerCancel = 1 }
| Supported AfTrigger values. More...
enum | AfPauseEnum { AfPauseImmediate = 0 , AfPauseDeferred = 1 , AfPauseResume = 2 }
| Supported AfPause values. More...
enum | AfStateEnum { AfStateIdle = 0 , AfStateScanning = 1 , AfStateFocused = 2 , AfStateFailed = 3 }
| Supported AfState values. More...
enum | AfPauseStateEnum { AfPauseStateRunning = 0 , AfPauseStatePausing = 1 , AfPauseStatePaused = 2 }
| Supported AfPauseState values. More...
enum | HdrModeEnum { HdrModeOff = 0 , HdrModeMultiExposureUnmerged = 1 , HdrModeMultiExposure = 2 , HdrModeSingleExposure = 3 , HdrModeNight = 4 }
| Supported HdrMode values. More...
enum | HdrChannelEnum { HdrChannelNone = 0 , HdrChannelShort = 1 , HdrChannelMedium = 2 , HdrChannelLong = 3 }
| Supported HdrChannel values. More...

## Variables
const ControlIdMap | controls
| List of all supported libcamera controls.
const Control< bool > | AeEnable
| Enable or disable the AEGC algorithm. When this control is set to true, both ExposureTimeMode and AnalogueGainMode are set to auto, and if this control is set to false then both are set to manual.
const std::array< const ControlValue, 3 > | AeStateValues
| List of all AeState supported values.
const std::map< std::string, int32_t > | AeStateNameValueMap
| Map of all AeState supported value names (in std::string format) to value.
const Control< int32_t > | AeState
| Report the AEGC algorithm state.
const std::array< const ControlValue, 4 > | AeMeteringModeValues
| List of all AeMeteringMode supported values.
const std::map< std::string, int32_t > | AeMeteringModeNameValueMap
| Map of all AeMeteringMode supported value names (in std::string format) to value.
const Control< int32_t > | AeMeteringMode
| Specify a metering mode for the AE algorithm to use.
const std::array< const ControlValue, 4 > | AeConstraintModeValues
| List of all AeConstraintMode supported values.
const std::map< std::string, int32_t > | AeConstraintModeNameValueMap
| Map of all AeConstraintMode supported value names (in std::string format) to value.
const Control< int32_t > | AeConstraintMode
| Specify a constraint mode for the AE algorithm to use.
const std::array< const ControlValue, 4 > | AeExposureModeValues
| List of all AeExposureMode supported values.
const std::map< std::string, int32_t > | AeExposureModeNameValueMap
| Map of all AeExposureMode supported value names (in std::string format) to value.
const Control< int32_t > | AeExposureMode
| Specify an exposure mode for the AE algorithm to use.
const Control< float > | ExposureValue
| Specify an Exposure Value (EV) parameter.
const Control< int32_t > | ExposureTime
| Exposure time for the frame applied in the sensor device.
const std::array< const ControlValue, 2 > | ExposureTimeModeValues
| List of all ExposureTimeMode supported values.
const std::map< std::string, int32_t > | ExposureTimeModeNameValueMap
| Map of all ExposureTimeMode supported value names (in std::string format) to value.
const Control< int32_t > | ExposureTimeMode
| Controls the source of the exposure time that is applied to the image sensor.
const Control< float > | AnalogueGain
| Analogue gain value applied in the sensor device.
const std::array< const ControlValue, 2 > | AnalogueGainModeValues
| List of all AnalogueGainMode supported values.
const std::map< std::string, int32_t > | AnalogueGainModeNameValueMap
| Map of all AnalogueGainMode supported value names (in std::string format) to value.
const Control< int32_t > | AnalogueGainMode
| Controls the source of the analogue gain that is applied to the image sensor.
const std::array< const ControlValue, 3 > | AeFlickerModeValues
| List of all AeFlickerMode supported values.
const std::map< std::string, int32_t > | AeFlickerModeNameValueMap
| Map of all AeFlickerMode supported value names (in std::string format) to value.
const Control< int32_t > | AeFlickerMode
| Set the flicker avoidance mode for AGC/AEC.
const Control< int32_t > | AeFlickerPeriod
| Manual flicker period in microseconds.
const Control< int32_t > | AeFlickerDetected
| Flicker period detected in microseconds.
const Control< float > | Brightness
| Specify a fixed brightness parameter.
const Control< float > | Contrast
| Specify a fixed contrast parameter.
const Control< float > | Lux
| Report an estimate of the current illuminance level in lux.
const Control< bool > | AwbEnable
| Enable or disable the AWB.
const std::array< const ControlValue, 8 > | AwbModeValues
| List of all AwbMode supported values.
const std::map< std::string, int32_t > | AwbModeNameValueMap
| Map of all AwbMode supported value names (in std::string format) to value.
const Control< int32_t > | AwbMode
| Specify the range of illuminants to use for the AWB algorithm.
const Control< bool > | AwbLocked
| Report the lock status of a running AWB algorithm.
const Control< Span< const float, 2 > > | ColourGains
| Pair of gain values for the Red and Blue colour channels, in that order.
const Control< int32_t > | ColourTemperature
| ColourTemperature of the frame, in kelvin.
const Control< float > | Saturation
| Specify a fixed saturation parameter.
const Control< Span< const int32_t, 4 > > | SensorBlackLevels
| Reports the sensor black levels used for processing a frame.
const Control< float > | Sharpness
| Intensity of the sharpening applied to the image.
const Control< int32_t > | FocusFoM
| Reports a Figure of Merit (FoM) to indicate how in-focus the frame is.
const Control< Span< const float, 9 > > | ColourCorrectionMatrix
| The 3x3 matrix that converts camera RGB to sRGB within the imaging pipeline.
const Control< Rectangle > | ScalerCrop
| Sets the image portion that will be scaled to form the whole of the final output image.
const Control< float > | DigitalGain
| Digital gain value applied during the processing steps applied to the image as captured from the sensor.
const Control< int64_t > | FrameDuration
| The instantaneous frame duration from start of frame exposure to start of next exposure, expressed in microseconds.
const Control< Span< const int64_t, 2 > > | FrameDurationLimits
| The minimum and maximum (in that order) frame duration, expressed in microseconds.
const Control< float > | SensorTemperature
| Temperature measure from the camera sensor in Celsius.
const Control< int64_t > | SensorTimestamp
| The time when the first row of the image sensor active array is exposed.
const std::array< const ControlValue, 3 > | AfModeValues
| List of all AfMode supported values.
const std::map< std::string, int32_t > | AfModeNameValueMap
| Map of all AfMode supported value names (in std::string format) to value.
const Control< int32_t > | AfMode
| The mode of the AF (autofocus) algorithm.
const std::array< const ControlValue, 3 > | AfRangeValues
| List of all AfRange supported values.
const std::map< std::string, int32_t > | AfRangeNameValueMap
| Map of all AfRange supported value names (in std::string format) to value.
const Control< int32_t > | AfRange
| The range of focus distances that is scanned.
const std::array< const ControlValue, 2 > | AfSpeedValues
| List of all AfSpeed supported values.
const std::map< std::string, int32_t > | AfSpeedNameValueMap
| Map of all AfSpeed supported value names (in std::string format) to value.
const Control< int32_t > | AfSpeed
| Determine whether the AF is to move the lens as quickly as possible or more steadily.
const std::array< const ControlValue, 2 > | AfMeteringValues
| List of all AfMetering supported values.
const std::map< std::string, int32_t > | AfMeteringNameValueMap
| Map of all AfMetering supported value names (in std::string format) to value.
const Control< int32_t > | AfMetering
| The parts of the image used by the AF algorithm to measure focus.
const Control< Span< const Rectangle > > | AfWindows
| The focus windows used by the AF algorithm when AfMetering is set to AfMeteringWindows.
const std::array< const ControlValue, 2 > | AfTriggerValues
| List of all AfTrigger supported values.
const std::map< std::string, int32_t > | AfTriggerNameValueMap
| Map of all AfTrigger supported value names (in std::string format) to value.
const Control< int32_t > | AfTrigger
| Start an autofocus scan.
const std::array< const ControlValue, 3 > | AfPauseValues
| List of all AfPause supported values.
const std::map< std::string, int32_t > | AfPauseNameValueMap
| Map of all AfPause supported value names (in std::string format) to value.
const Control< int32_t > | AfPause
| Pause lens movements when in continuous autofocus mode.
const Control< float > | LensPosition
| Set and report the focus lens position.
const std::array< const ControlValue, 4 > | AfStateValues
| List of all AfState supported values.
const std::map< std::string, int32_t > | AfStateNameValueMap
| Map of all AfState supported value names (in std::string format) to value.
const Control< int32_t > | AfState
| The current state of the AF algorithm.
const std::array< const ControlValue, 3 > | AfPauseStateValues
| List of all AfPauseState supported values.
const std::map< std::string, int32_t > | AfPauseStateNameValueMap
| Map of all AfPauseState supported value names (in std::string format) to value.
const Control< int32_t > | AfPauseState
| Report whether the autofocus is currently running, paused or pausing.
const std::array< const ControlValue, 5 > | HdrModeValues
| List of all HdrMode supported values.
const std::map< std::string, int32_t > | HdrModeNameValueMap
| Map of all HdrMode supported value names (in std::string format) to value.
const Control< int32_t > | HdrMode
| Set the mode to be used for High Dynamic Range (HDR) imaging.
const std::array< const ControlValue, 4 > | HdrChannelValues
| List of all HdrChannel supported values.
const std::map< std::string, int32_t > | HdrChannelNameValueMap
| Map of all HdrChannel supported value names (in std::string format) to value.
const Control< int32_t > | HdrChannel
| The HDR channel used to capture the frame.
const Control< float > | Gamma
| Specify a fixed gamma value.
const Control< bool > | DebugMetadataEnable
| Enable or disable the debug metadata.

## Detailed Description

Namespace for libcamera controls.

## Enumeration Type Documentation

## ◆ AeConstraintModeEnum

enum libcamera::controls::AeConstraintModeEnum

Supported AeConstraintMode values.

Enumerator
ConstraintNormal | Default constraint mode. This mode aims to balance the exposure of different parts of the image so as to reach a reasonable average level. However, highlights in the image may appear over-exposed and lowlights may appear under-exposed.
ConstraintHighlight | Highlight constraint mode. This mode adjusts the exposure levels in order to try and avoid over-exposing the brightest parts (highlights) of an image. Other non-highlight parts of the image may appear under-exposed.
ConstraintShadows | Shadows constraint mode. This mode adjusts the exposure levels in order to try and avoid under-exposing the dark parts (shadows) of an image. Other normally exposed parts of the image may appear over-exposed.
ConstraintCustom | Custom constraint mode.

## ◆ AeExposureModeEnum

enum libcamera::controls::AeExposureModeEnum

Supported AeExposureMode values.

Enumerator
ExposureNormal | Default exposure mode.
ExposureShort | Exposure mode allowing only short exposure times.
ExposureLong | Exposure mode allowing long exposure times.
ExposureCustom | Custom exposure mode.

## ◆ AeFlickerModeEnum

enum libcamera::controls::AeFlickerModeEnum

Supported AeFlickerMode values.

Enumerator
FlickerOff | No flicker avoidance is performed.
FlickerManual | Manual flicker avoidance. Suppress flicker effects caused by lighting running with a period specified by the AeFlickerPeriod control. See also AeFlickerPeriod
FlickerAuto | Automatic flicker period detection and avoidance. The system will automatically determine the most likely value of flicker period, and avoid flicker of this frequency. Once flicker is being corrected, it is implementation dependent whether the system is still able to detect a change in the flicker period. See also AeFlickerDetected

## ◆ AeMeteringModeEnum

enum libcamera::controls::AeMeteringModeEnum

Supported AeMeteringMode values.

Enumerator
MeteringCentreWeighted | Centre-weighted metering mode.
MeteringSpot | Spot metering mode.
MeteringMatrix | Matrix metering mode.
MeteringCustom | Custom metering mode.

## ◆ AeStateEnum

enum libcamera::controls::AeStateEnum

Supported AeState values.

Enumerator
AeStateIdle | The AEGC algorithm is inactive. This state is returned when both AnalogueGainMode and ExposureTimeMode are set to Manual and the algorithm is not actively computing any value.
AeStateSearching | The AEGC algorithm is actively computing new values, for either the exposure time or the analogue gain, but has not converged to a stable result yet. This state is returned if at least one of AnalogueGainMode or ExposureTimeMode is auto and the algorithm hasn't converged yet. The AEGC algorithm converges once stable values are computed for all of the controls set to be computed in Auto mode. Once the algorithm converges the state is moved to AeStateConverged.
AeStateConverged | The AEGC algorithm has converged. This state is returned if at least one of AnalogueGainMode or ExposureTimeMode is Auto, and the AEGC algorithm has converged to a stable value. If the measurements move too far away from the convergence point then the AEGC algorithm might start adjusting again, in which case the state is moved to AeStateSearching.

## ◆ AfMeteringEnum

enum libcamera::controls::AfMeteringEnum

Supported AfMetering values.

Enumerator
AfMeteringAuto | Let the AF algorithm decide for itself where it will measure focus.
AfMeteringWindows | Use the rectangles defined by the AfWindows control to measure focus. If no windows are specified the behaviour is platform dependent.

## ◆ AfModeEnum

enum libcamera::controls::AfModeEnum

Supported AfMode values.

Enumerator
AfModeManual | The AF algorithm is in manual mode. In this mode it will never perform any action nor move the lens of its own accord, but an application can specify the desired lens position using the LensPosition control. The AfState will always report AfStateIdle. If the camera is started in AfModeManual, it will move the focus lens to the position specified by the LensPosition control. This mode is the recommended default value for the AfMode control. External cameras (as reported by the Location property set to CameraLocationExternal) may use a different default value.
AfModeAuto | The AF algorithm is in auto mode. In this mode the algorithm will never move the lens or change state unless the AfTrigger control is used. The AfTrigger control can be used to initiate a focus scan, the results of which will be reported by AfState. If the autofocus algorithm is moved from AfModeAuto to another mode while a scan is in progress, the scan is cancelled immediately, without waiting for the scan to finish. When first entering this mode the AfState will report AfStateIdle. When a trigger control is sent, AfState will report AfStateScanning for a period before spontaneously changing to AfStateFocused or AfStateFailed, depending on the outcome of the scan. It will remain in this state until another scan is initiated by the AfTrigger control. If a scan is cancelled (without changing to another mode), AfState will return to AfStateIdle.
AfModeContinuous | The AF algorithm is in continuous mode. In this mode the lens can re-start a scan spontaneously at any moment, without any user intervention. The AfState still reports whether the algorithm is currently scanning or not, though the application has no ability to initiate or cancel scans, nor to move the lens for itself. However, applications can pause the AF algorithm from continuously scanning by using the AfPause control. This allows video or still images to be captured whilst guaranteeing that the focus is fixed. When set to AfModeContinuous, the system will immediately initiate a scan so AfState will report AfStateScanning, and will settle on one of AfStateFocused or AfStateFailed, depending on the scan result.

## ◆ AfPauseEnum

enum libcamera::controls::AfPauseEnum

Supported AfPause values.

Enumerator
AfPauseImmediate | Pause the continuous autofocus algorithm immediately. The autofocus algorithm is paused whether or not any kind of scan is underway. AfPauseState will subsequently report AfPauseStatePaused. AfState may report any of AfStateScanning, AfStateFocused or AfStateFailed, depending on the algorithm's state when it received this control.
AfPauseDeferred | Pause the continuous autofocus algorithm at the end of the scan. This is similar to AfPauseImmediate, and if the AfState is currently reporting AfStateFocused or AfStateFailed it will remain in that state and AfPauseState will report AfPauseStatePaused. However, if the algorithm is scanning (AfStateScanning), AfPauseState will report AfPauseStatePausing until the scan is finished, at which point AfState will report one of AfStateFocused or AfStateFailed, and AfPauseState will change to AfPauseStatePaused.
AfPauseResume | Resume continuous autofocus operation. The algorithm starts again from exactly where it left off, and AfPauseState will report AfPauseStateRunning.

## ◆ AfPauseStateEnum

enum libcamera::controls::AfPauseStateEnum

Supported AfPauseState values.

Enumerator
AfPauseStateRunning | Continuous AF is running and the algorithm may restart a scan spontaneously.
AfPauseStatePausing | Continuous AF has been sent an AfPauseDeferred control, and will pause as soon as any in-progress scan completes. When the scan completes, the AfPauseState control will report AfPauseStatePaused. No new scans will be start spontaneously until the AfPauseResume control is sent.
AfPauseStatePaused | Continuous AF is paused. No further state changes or lens movements will occur until the AfPauseResume control is sent.

## ◆ AfRangeEnum

enum libcamera::controls::AfRangeEnum

Supported AfRange values.

Enumerator
AfRangeNormal | A wide range of focus distances is scanned. Scanned distances cover all the way from infinity down to close distances, though depending on the implementation, possibly not including the very closest macro positions.
AfRangeMacro | Only close distances are scanned.
AfRangeFull | The full range of focus distances is scanned. This range is similar to AfRangeNormal but includes the very closest macro positions.

## ◆ AfSpeedEnum

enum libcamera::controls::AfSpeedEnum

Supported AfSpeed values.

Enumerator
AfSpeedNormal | Move the lens at its usual speed.
AfSpeedFast | Move the lens more quickly.

## ◆ AfStateEnum

enum libcamera::controls::AfStateEnum

Supported AfState values.

Enumerator
AfStateIdle | The AF algorithm is in manual mode (AfModeManual) or in auto mode (AfModeAuto) and a scan has not yet been triggered, or an in-progress scan was cancelled.
AfStateScanning | The AF algorithm is in auto mode (AfModeAuto), and a scan has been started using the AfTrigger control. The scan can be cancelled by sending AfTriggerCancel at which point the algorithm will either move back to AfStateIdle or, if the scan actually completes before the cancel request is processed, to one of AfStateFocused or AfStateFailed. Alternatively the AF algorithm could be in continuous mode (AfModeContinuous) at which point it may enter this state spontaneously whenever it determines that a rescan is needed.
AfStateFocused | The AF algorithm is in auto (AfModeAuto) or continuous (AfModeContinuous) mode and a scan has completed with the result that the algorithm believes the image is now in focus.
AfStateFailed | The AF algorithm is in auto (AfModeAuto) or continuous (AfModeContinuous) mode and a scan has completed with the result that the algorithm did not find a good focus position.

## ◆ AfTriggerEnum

enum libcamera::controls::AfTriggerEnum

Supported AfTrigger values.

Enumerator
AfTriggerStart | Start an AF scan. Setting the control to AfTriggerStart is ignored if a scan is in progress.
AfTriggerCancel | Cancel an AF scan. This does not cause the lens to move anywhere else. Ignored if no scan is in progress.

## ◆ AnalogueGainModeEnum

enum libcamera::controls::AnalogueGainModeEnum

Supported AnalogueGainMode values.

Enumerator
AnalogueGainModeAuto | The analogue gain will be calculated automatically and set by the AEGC algorithm. If AnalogueGain is set while this mode is active, it will be ignored, and it will also not be retained. When transitioning from Manual to Auto mode, the AEGC should start its adjustments based on the last set manual AnalogueGain value.
AnalogueGainModeManual | The analogue gain will not be updated by the AEGC algorithm. When transitioning from Auto to Manual mode, the last computed gain value is used until a new value is specified through the AnalogueGain control. If an AnalogueGain value is specified in the same request where the AnalogueGainMode is changed from Auto to Manual, the provided AnalogueGain is applied immediately.

## ◆ AwbModeEnum

enum libcamera::controls::AwbModeEnum

Supported AwbMode values.

Enumerator
AwbAuto | Search over the whole colour temperature range.
AwbIncandescent | Incandescent AWB lamp mode.
AwbTungsten | Tungsten AWB lamp mode.
AwbFluorescent | Fluorescent AWB lamp mode.
AwbIndoor | Indoor AWB lighting mode.
AwbDaylight | Daylight AWB lighting mode.
AwbCloudy | Cloudy AWB lighting mode.
AwbCustom | Custom AWB mode.

## ◆ ExposureTimeModeEnum

enum libcamera::controls::ExposureTimeModeEnum

Supported ExposureTimeMode values.

Enumerator
ExposureTimeModeAuto | The exposure time will be calculated automatically and set by the AE algorithm. If ExposureTime is set while this mode is active, it will be ignored, and its value will not be retained. When transitioning from Manual to Auto mode, the AEGC should start its adjustments based on the last set manual ExposureTime value.
ExposureTimeModeManual | The exposure time will not be updated by the AE algorithm. When transitioning from Auto to Manual mode, the last computed exposure value is used until a new value is specified through the ExposureTime control. If an ExposureTime value is specified in the same request where the ExposureTimeMode is changed from Auto to Manual, the provided ExposureTime is applied immediately.

## ◆ HdrChannelEnum

enum libcamera::controls::HdrChannelEnum

Supported HdrChannel values.

Enumerator
HdrChannelNone | This image does not correspond to any of the captures used to create an HDR image.
HdrChannelShort | This is a short exposure image.
HdrChannelMedium | This is a medium exposure image.
HdrChannelLong | This is a long exposure image.

## ◆ HdrModeEnum

enum libcamera::controls::HdrModeEnum

Supported HdrMode values.

Enumerator
HdrModeOff | HDR is disabled. Metadata for this frame will not include the HdrChannel control.
HdrModeMultiExposureUnmerged | Multiple exposures will be generated in an alternating fashion. The multiple exposures will not be merged together and will be returned to the application as they are. Each image will be tagged with the correct HDR channel, indicating what kind of exposure it is. The tag should be the same as in the HdrModeMultiExposure case. The expectation is that an application using this mode would merge the frames to create HDR images for itself if it requires them.
HdrModeMultiExposure | Multiple exposures will be generated and merged to create HDR images. Each image will be tagged with the HDR channel (long, medium or short) that arrived and which caused this image to be output. Systems that use two channels for HDR will return images tagged alternately as the short and long channel. Systems that use three channels for HDR will cycle through the short, medium and long channel before repeating.
HdrModeSingleExposure | Multiple frames all at a single exposure will be used to create HDR images. These images should be reported as all corresponding to the HDR short channel.
HdrModeNight | Multiple frames will be combined to produce "night mode" images. It is up to the implementation exactly which HDR channels it uses, and the images will all be tagged accordingly with the correct HDR channel information.

## Variable Documentation

## ◆ AeConstraintMode

const Control<int32_t> libcamera::controls::AeConstraintMode
| extern

Specify a constraint mode for the AE algorithm to use.

The constraint modes determine how the measured scene brightness is adjusted to reach the desired target exposure. Constraint modes may be platform specific, and not all constraint modes may be supported.

## ◆ AeEnable

const Control<bool> libcamera::controls::AeEnable
| extern

Enable or disable the AEGC algorithm. When this control is set to true, both ExposureTimeMode and AnalogueGainMode are set to auto, and if this control is set to false then both are set to manual.

If ExposureTimeMode or AnalogueGainMode are also set in the same request as AeEnable, then the modes supplied by ExposureTimeMode or AnalogueGainMode will take precedence.

See also
  ExposureTimeMode AnalogueGainMode

## ◆ AeExposureMode

const Control<int32_t> libcamera::controls::AeExposureMode
| extern

Specify an exposure mode for the AE algorithm to use.

The exposure modes specify how the desired total exposure is divided between the exposure time and the sensor's analogue gain. They are platform specific, and not all exposure modes may be supported.

When one of AnalogueGainMode or ExposureTimeMode is set to Manual, the fixed values will override any choices made by AeExposureMode.

See also
  AnalogueGainMode
  ExposureTimeMode

## ◆ AeFlickerDetected

const Control<int32_t> libcamera::controls::AeFlickerDetected
| extern

Flicker period detected in microseconds.

The value reported here indicates the currently detected flicker period, or zero if no flicker at all is detected.

When AeFlickerMode is set to FlickerAuto, there may be a period during which the value reported here remains zero. Once a non-zero value is reported, then this is the flicker period that has been detected and is now being cancelled.

In the case of 50Hz mains flicker, the value would be 10000 (corresponding to 100Hz), or 8333 (120Hz) for 60Hz mains flicker.

It is implementation dependent whether the system can continue to detect flicker of different periods when another frequency is already being cancelled.

See also
  AeFlickerMode

## ◆ AeFlickerMode

const Control<int32_t> libcamera::controls::AeFlickerMode
| extern

Set the flicker avoidance mode for AGC/AEC.

The flicker mode determines whether, and how, the AGC/AEC algorithm attempts to hide flicker effects caused by the duty cycle of artificial lighting.

Although implementation dependent, many algorithms for "flicker avoidance" work by restricting this exposure time to integer multiples of the cycle period, wherever possible.

Implementations may not support all of the flicker modes listed below.

By default the system will start in FlickerAuto mode if this is supported, otherwise the flicker mode will be set to FlickerOff.

## ◆ AeFlickerPeriod

const Control<int32_t> libcamera::controls::AeFlickerPeriod
| extern

Manual flicker period in microseconds.

This value sets the current flicker period to avoid. It is used when AeFlickerMode is set to FlickerManual.

To cancel 50Hz mains flicker, this should be set to 10000 (corresponding to 100Hz), or 8333 (120Hz) for 60Hz mains.

Setting the mode to FlickerManual when no AeFlickerPeriod has ever been set means that no flicker cancellation occurs (until the value of this control is updated).

Switching to modes other than FlickerManual has no effect on the value of the AeFlickerPeriod control.

See also
  AeFlickerMode

## ◆ AeMeteringMode

const Control<int32_t> libcamera::controls::AeMeteringMode
| extern

Specify a metering mode for the AE algorithm to use.

The metering modes determine which parts of the image are used to determine the scene brightness. Metering modes may be platform specific and not all metering modes may be supported.

## ◆ AeState

const Control<int32_t> libcamera::controls::AeState
| extern

Report the AEGC algorithm state.

The AEGC algorithm computes the exposure time and the analogue gain to be applied to the image sensor.

The AEGC algorithm behaviour is controlled by the ExposureTimeMode and AnalogueGainMode controls, which allow applications to decide how the exposure time and gain are computed, in Auto or Manual mode, independently from one another.

The AeState control reports the AEGC algorithm state through a single value and describes it as a single computation block which computes both the exposure time and the analogue gain values.

When both the exposure time and analogue gain values are configured to be in Manual mode, the AEGC algorithm is quiescent and does not actively compute any value and the AeState control will report AeStateIdle.

When at least the exposure time or analogue gain are configured to be computed by the AEGC algorithm, the AeState control will report if the algorithm has converged to stable values for all of the controls set to be computed in Auto mode.

See also
  AnalogueGainMode
  ExposureTimeMode

## ◆ AfMode

const Control<int32_t> libcamera::controls::AfMode
| extern

The mode of the AF (autofocus) algorithm.

An implementation may choose not to implement all the modes.

## ◆ AfPause

const Control<int32_t> libcamera::controls::AfPause
| extern

Pause lens movements when in continuous autofocus mode.

This control has no effect except when in continuous autofocus mode (AfModeContinuous). It can be used to pause any lens movements while (for example) images are captured. The algorithm remains inactive until it is instructed to resume.

## ◆ AfPauseState

const Control<int32_t> libcamera::controls::AfPauseState
| extern

Report whether the autofocus is currently running, paused or pausing.

This control is only applicable in continuous (AfModeContinuous) mode, and reports whether the algorithm is currently running, paused or pausing (that is, will pause as soon as any in-progress scan completes).

Any change to AfMode will cause AfPauseStateRunning to be reported.

## ◆ AfRange

const Control<int32_t> libcamera::controls::AfRange
| extern

The range of focus distances that is scanned.

An implementation may choose not to implement all the options here.

## ◆ AfSpeed

const Control<int32_t> libcamera::controls::AfSpeed
| extern

Determine whether the AF is to move the lens as quickly as possible or more steadily.

For example, during video recording it may be desirable not to move the lens too abruptly, but when in a preview mode (waiting for a still capture) it may be helpful to move the lens as quickly as is reasonably possible.

## ◆ AfState

const Control<int32_t> libcamera::controls::AfState
| extern

The current state of the AF algorithm.

This control reports the current state of the AF algorithm in conjunction with the reported AfMode value and (in continuous AF mode) the AfPauseState value. The possible state changes are described below, though we note the following state transitions that occur when the AfMode is changed.

If the AfMode is set to AfModeManual, then the AfState will always report AfStateIdle (even if the lens is subsequently moved). Changing to the AfModeManual state does not initiate any lens movement.

If the AfMode is set to AfModeAuto then the AfState will report AfStateIdle. However, if AfModeAuto and AfTriggerStart are sent together then AfState will omit AfStateIdle and move straight to AfStateScanning (and start a scan).

If the AfMode is set to AfModeContinuous then the AfState will initially report AfStateScanning.

## ◆ AfTrigger

const Control<int32_t> libcamera::controls::AfTrigger
| extern

Start an autofocus scan.

This control starts an autofocus scan when AfMode is set to AfModeAuto, and is ignored if AfMode is set to AfModeManual or AfModeContinuous. It can also be used to terminate a scan early.

## ◆ AfWindows

const Control<Span<const Rectangle> > libcamera::controls::AfWindows
| extern

The focus windows used by the AF algorithm when AfMetering is set to AfMeteringWindows.

The units used are pixels within the rectangle returned by the ScalerCropMaximum property.

In order to be activated, a rectangle must be programmed with non-zero width and height. Internally, these rectangles are intersected with the ScalerCropMaximum rectangle. If the window becomes empty after this operation, then the window is ignored. If all the windows end up being ignored, then the behaviour is platform dependent.

On platforms that support the ScalerCrop control (for implementing digital zoom, for example), no automatic recalculation or adjustment of AF windows is performed internally if the ScalerCrop is changed. If any window lies outside the output image after the scaler crop has been applied, it is up to the application to recalculate them.

The details of how the windows are used are platform dependent. We note that when there is more than one AF window, a typical implementation might find the optimal focus position for each one and finally select the window where the focal distance for the objects shown in that part of the image are closest to the camera.

## ◆ AnalogueGain

const Control<float> libcamera::controls::AnalogueGain
| extern

Analogue gain value applied in the sensor device.

The value of the control specifies the gain multiplier applied to all colour channels. This value cannot be lower than 1.0.

This control will only take effect if AnalogueGainMode is Manual. If this control is set when AnalogueGainMode is Auto, the value will be ignored and will not be retained.

When reported in metadata, this control indicates what analogue gain was used for the current request, regardless of AnalogueGainMode. AnalogueGainMode will indicate the source of the analogue gain value, whether it came from the AEGC algorithm or not.

See also
  ExposureTime
  AnalogueGainMode

## ◆ AnalogueGainMode

const Control<int32_t> libcamera::controls::AnalogueGainMode
| extern

Controls the source of the analogue gain that is applied to the image sensor.

When set to Auto, the AEGC algorithm computes the analogue gain and configures the image sensor accordingly. When set to Manual, the value of the AnalogueGain control is used.

When transitioning from Auto to Manual mode and no AnalogueGain control is provided by the application, the last value computed by the AEGC algorithm when the mode was Auto will be used. If the AnalogueGainMode was never set to Auto (either because the camera started in Manual mode, or Auto is not supported by the camera), the camera should use a best-effort default value.

If AnalogueGainModeManual is supported, the AnalogueGain control must also be supported.

For cameras where we have control over the ISP, both ExposureTimeMode and AnalogueGainMode are expected to support manual mode, and both controls (as well as ExposureTimeMode and AnalogueGain) are expected to be present. If the camera also has an AEGC implementation, both ExposureTimeMode and AnalogueGainMode shall support both manual and auto mode. If auto mode is available, it shall be the default mode. These rules do not apply to black box cameras such as UVC cameras, where the available gain and exposure modes are completely dependent on what the hardware exposes.

The same procedure described for performing flickerless transitions in the ExposureTimeMode control documentation can be applied to analogue gain.

See also
  ExposureTimeMode
  AnalogueGain

## ◆ AwbEnable

const Control<bool> libcamera::controls::AwbEnable
| extern

Enable or disable the AWB.

When AWB is enabled, the algorithm estimates the colour temperature of the scene and computes colour gains and the colour correction matrix automatically. The computed colour temperature, gains and correction matrix are reported in metadata. The corresponding controls are ignored if set in a request.

When AWB is disabled, the colour temperature, gains and correction matrix are not updated automatically and can be set manually in requests.

See also
  ColourCorrectionMatrix
  ColourGains
  ColourTemperature

## ◆ AwbLocked

const Control<bool> libcamera::controls::AwbLocked
| extern

Report the lock status of a running AWB algorithm.

If the AWB algorithm is locked the value shall be set to true, if it's converging it shall be set to false. If the AWB algorithm is not running the control shall not be present in the metadata control list.

See also
  AwbEnable

## ◆ AwbMode

const Control<int32_t> libcamera::controls::AwbMode
| extern

Specify the range of illuminants to use for the AWB algorithm.

The modes supported are platform specific, and not all modes may be supported.

## ◆ Brightness

const Control<float> libcamera::controls::Brightness
| extern

Specify a fixed brightness parameter.

Positive values (up to 1.0) produce brighter images; negative values (up to -1.0) produce darker images and 0.0 leaves pixels unchanged.

## ◆ ColourCorrectionMatrix

const Control<Span<const float, 9> > libcamera::controls::ColourCorrectionMatrix
| extern

The 3x3 matrix that converts camera RGB to sRGB within the imaging pipeline.

This should describe the matrix that is used after pixels have been white-balanced, but before any gamma transformation. The 3x3 matrix is stored in conventional reading order in an array of 9 floating point values.

ColourCorrectionMatrix can only be applied in a Request when the AWB is disabled.

See also
  AwbEnable
  ColourTemperature

## ◆ ColourGains

const Control<Span<const float, 2> > libcamera::controls::ColourGains
| extern

Pair of gain values for the Red and Blue colour channels, in that order.

ColourGains can only be applied in a Request when the AWB is disabled. If ColourGains is set in a request but ColourTemperature is not, the implementation shall calculate and set the ColourTemperature based on the ColourGains.

See also
  AwbEnable
  ColourTemperature

## ◆ ColourTemperature

const Control<int32_t> libcamera::controls::ColourTemperature
| extern

ColourTemperature of the frame, in kelvin.

ColourTemperature can only be applied in a Request when the AWB is disabled.

If ColourTemperature is set in a request but ColourGains is not, the implementation shall calculate and set the ColourGains based on the given ColourTemperature. If ColourTemperature is set (either directly, or indirectly by setting ColourGains) but ColourCorrectionMatrix is not, the ColourCorrectionMatrix is updated based on the ColourTemperature.

The ColourTemperature used to process the frame is reported in metadata.

See also
  AwbEnable
  ColourCorrectionMatrix
  ColourGains

## ◆ Contrast

const Control<float> libcamera::controls::Contrast
| extern

Specify a fixed contrast parameter.

Normal contrast is given by the value 1.0; larger values produce images with more contrast.

## ◆ controls

const ControlIdMap libcamera::controls::controls
| extern

List of all supported libcamera controls.

Unless otherwise stated, all controls are bi-directional, i.e. they can be set through Request::controls() and returned out through Request::metadata().

## ◆ DigitalGain

const Control<float> libcamera::controls::DigitalGain
| extern

Digital gain value applied during the processing steps applied to the image as captured from the sensor.

The global digital gain factor is applied to all the colour channels of the RAW image. Different pipeline models are free to specify how the global gain factor applies to each separate channel.

If an imaging pipeline applies digital gain in distinct processing steps, this value indicates their total sum. Pipelines are free to decide how to adjust each processing step to respect the received gain factor and shall report their total value in the request metadata.

## ◆ ExposureTime

const Control<int32_t> libcamera::controls::ExposureTime
| extern

Exposure time for the frame applied in the sensor device.

This value is specified in micro-seconds.

This control will only take effect if ExposureTimeMode is Manual. If this control is set when ExposureTimeMode is Auto, the value will be ignored and will not be retained.

When reported in metadata, this control indicates what exposure time was used for the current frame, regardless of ExposureTimeMode. ExposureTimeMode will indicate the source of the exposure time value, whether it came from the AE algorithm or not.

See also
  AnalogueGain
  ExposureTimeMode

## ◆ ExposureTimeMode

const Control<int32_t> libcamera::controls::ExposureTimeMode
| extern

Controls the source of the exposure time that is applied to the image sensor.

When set to Auto, the AE algorithm computes the exposure time and configures the image sensor accordingly. When set to Manual, the value of the ExposureTime control is used.

When transitioning from Auto to Manual mode and no ExposureTime control is provided by the application, the last value computed by the AE algorithm when the mode was Auto will be used. If the ExposureTimeMode was never set to Auto (either because the camera started in Manual mode, or Auto is not supported by the camera), the camera should use a best-effort default value.

If ExposureTimeModeManual is supported, the ExposureTime control must also be supported.

Cameras that support manual control of the sensor shall support manual mode for both ExposureTimeMode and AnalogueGainMode, and shall expose the ExposureTime and AnalogueGain controls. If the camera also has an AEGC implementation, both ExposureTimeMode and AnalogueGainMode shall support both manual and auto mode. If auto mode is available, it shall be the default mode. These rules do not apply to black box cameras such as UVC cameras, where the available gain and exposure modes are completely dependent on what the device exposes.

Flickerless exposure mode transitions

Applications that wish to transition from ExposureTimeModeAuto to direct control of the exposure time without causing extra flicker can do so by selecting an ExposureTime value as close as possible to the last value computed by the auto exposure algorithm in order to avoid any visible flickering.

To select the correct value to use as ExposureTime value, applications should accommodate the natural delay in applying controls caused by the capture pipeline frame depth.

When switching to manual exposure mode, applications should not immediately specify an ExposureTime value in the same request where ExposureTimeMode is set to Manual. They should instead wait for the first Request where ExposureTimeMode is reported as ExposureTimeModeManual in the Request metadata, and use the reported ExposureTime to populate the control value in the next Request to be queued to the Camera.

The implementation of the auto-exposure algorithm should equally try to minimize flickering and when transitioning from manual exposure mode to auto exposure use the last value provided by the application as starting point.

1. Start with ExposureTimeMode set to Auto
2. Set ExposureTimeMode to Manual
3. Wait for the first completed request that has ExposureTimeMode set to Manual
4. Copy the value reported in ExposureTime into a new request, and submit it
5. Proceed to run manual exposure time as desired

See also
  ExposureTime

## ◆ ExposureValue

const Control<float> libcamera::controls::ExposureValue
| extern

Specify an Exposure Value (EV) parameter.

The EV parameter will only be applied if the AE algorithm is currently enabled, that is, at least one of AnalogueGainMode and ExposureTimeMode are in Auto mode.

By convention EV adjusts the exposure as log2. For example EV = [-2, -1, -0.5, 0, 0.5, 1, 2] results in an exposure adjustment of [1/4x, 1/2x, 1/sqrt(2)x, 1x, sqrt(2)x, 2x, 4x].

See also
  AnalogueGainMode
  ExposureTimeMode

## ◆ FocusFoM

const Control<int32_t> libcamera::controls::FocusFoM
| extern

Reports a Figure of Merit (FoM) to indicate how in-focus the frame is.

A larger FocusFoM value indicates a more in-focus frame. This singular value may be based on a combination of statistics gathered from multiple focus regions within an image. The number of focus regions and method of combination is platform dependent. In this respect, it is not necessarily aimed at providing a way to implement a focus algorithm by the application, rather an indication of how in-focus a frame is.

## ◆ FrameDuration

const Control<int64_t> libcamera::controls::FrameDuration
| extern

The instantaneous frame duration from start of frame exposure to start of next exposure, expressed in microseconds.

This control is meant to be returned in metadata.

## ◆ FrameDurationLimits

const Control<Span<const int64_t, 2> > libcamera::controls::FrameDurationLimits
| extern

The minimum and maximum (in that order) frame duration, expressed in microseconds.

When provided by applications, the control specifies the sensor frame duration interval the pipeline has to use. This limits the largest exposure time the sensor can use. For example, if a maximum frame duration of 33ms is requested (corresponding to 30 frames per second), the sensor will not be able to raise the exposure time above 33ms. A fixed frame duration is achieved by setting the minimum and maximum values to be the same. Setting both values to 0 reverts to using the camera defaults.

The maximum frame duration provides the absolute limit to the exposure time computed by the AE algorithm and it overrides any exposure mode setting specified with controls::AeExposureMode. Similarly, when a manual exposure time is set through controls::ExposureTime, it also gets clipped to the limits set by this control. When reported in metadata, the control expresses the minimum and maximum frame durations used after being clipped to the sensor provided frame duration limits.

See also
  AeExposureMode
  ExposureTime

Todo
  Define how to calculate the capture frame rate by defining controls to report additional delays introduced by the capture pipeline or post-processing stages (ie JPEG conversion, frame scaling).

Todo
  Provide an explicit definition of default control values, for this and all other controls.

## ◆ Gamma

const Control<float> libcamera::controls::Gamma
| extern

Specify a fixed gamma value.

The default gamma value must be 2.2 which closely mimics sRGB gamma. Note that this is camera gamma, so it is applied as 1.0/gamma.

## ◆ HdrChannel

const Control<int32_t> libcamera::controls::HdrChannel
| extern

The HDR channel used to capture the frame.

This value is reported back to the application so that it can discover whether this capture corresponds to the short or long exposure image (or any other image used by the HDR procedure). An application can monitor the HDR channel to discover when the differently exposed images have arrived.

This metadata is only available when an HDR mode has been enabled.

See also
  HdrMode

## ◆ HdrMode

const Control<int32_t> libcamera::controls::HdrMode
| extern

Set the mode to be used for High Dynamic Range (HDR) imaging.

HDR techniques typically include multiple exposure, image fusion and tone mapping techniques to improve the dynamic range of the resulting images.

When using an HDR mode, images are captured with different sets of AGC settings called HDR channels. Channels indicate in particular the type of exposure (short, medium or long) used to capture the raw image, before fusion. Each HDR image is tagged with the corresponding channel using the HdrChannel control.

See also
  HdrChannel

## ◆ LensPosition

const Control<float> libcamera::controls::LensPosition
| extern

Set and report the focus lens position.

This control instructs the lens to move to a particular position and also reports back the position of the lens for each frame.

The LensPosition control is ignored unless the AfMode is set to AfModeManual, though the value is reported back unconditionally in all modes.

This value, which is generally a non-integer, is the reciprocal of the focal distance in metres, also known as dioptres. That is, to set a focal distance D, the lens position LP is given by

For example:

- 0 moves the lens to infinity.
- 0.5 moves the lens to focus on objects 2m away.
- 2 moves the lens to focus on objects 50cm away.
- And larger values will focus the lens closer.

The default value of the control should indicate a good general position for the lens, often corresponding to the hyperfocal distance (the closest position for which objects at infinity are still acceptably sharp). The minimum will often be zero (meaning infinity), and the maximum value defines the closest focus position.

Todo
  Define a property to report the Hyperfocal distance of calibrated lenses.

## ◆ Lux

const Control<float> libcamera::controls::Lux
| extern

Report an estimate of the current illuminance level in lux.

The Lux control can only be returned in metadata.

## ◆ Saturation

const Control<float> libcamera::controls::Saturation
| extern

Specify a fixed saturation parameter.

Normal saturation is given by the value 1.0; larger values produce more saturated colours; 0.0 produces a greyscale image.

## ◆ ScalerCrop

const Control<Rectangle> libcamera::controls::ScalerCrop
| extern

Sets the image portion that will be scaled to form the whole of the final output image.

The (x,y) location of this rectangle is relative to the PixelArrayActiveAreas that is being used. The units remain native sensor pixels, even if the sensor is being used in a binning or skipping mode.

This control is only present when the pipeline supports scaling. Its maximum valid value is given by the properties::ScalerCropMaximum property, and the two can be used to implement digital zoom.

## ◆ SensorBlackLevels

const Control<Span<const int32_t, 4> > libcamera::controls::SensorBlackLevels
| extern

Reports the sensor black levels used for processing a frame.

The values are in the order R, Gr, Gb, B. They are returned as numbers out of a 16-bit pixel range (as if pixels ranged from 0 to 65535). The SensorBlackLevels control can only be returned in metadata.

## ◆ SensorTemperature

const Control<float> libcamera::controls::SensorTemperature
| extern

Temperature measure from the camera sensor in Celsius.

This value is typically obtained by a thermal sensor present on-die or in the camera module. The range of reported temperatures is device dependent.

The SensorTemperature control will only be returned in metadata if a thermal sensor is present.

## ◆ SensorTimestamp

const Control<int64_t> libcamera::controls::SensorTimestamp
| extern

The time when the first row of the image sensor active array is exposed.

The timestamp, expressed in nanoseconds, represents a monotonically increasing counter since the system boot time, as defined by the Linux-specific CLOCK_BOOTTIME clock id.

The SensorTimestamp control can only be returned in metadata.

Todo
  Define how the sensor timestamp has to be used in the reprocessing use case.

## ◆ Sharpness

const Control<float> libcamera::controls::Sharpness
| extern

Intensity of the sharpening applied to the image.

A value of 0.0 means no sharpening. The minimum value means minimal sharpening, and shall be 0.0 unless the camera can't disable sharpening completely. The default value shall give a "reasonable" level of sharpening, suitable for most use cases. The maximum value may apply extremely high levels of sharpening, higher than anyone could reasonably want. Negative values are not allowed. Note also that sharpening is not applied to raw streams.