# SPDX-License-Identifier: LGPL-2.1-or-later
#
# Copyright (C) 2019, Google Inc.
#
%YAML 1.1
---
# Unless otherwise stated, all controls are bi-directional, i.e. they can be
# set through Request::controls() and returned out through Request::metadata().
vendor: libcamera
controls:
  - AeEnable:
      type: bool
      direction: in
      description: |
        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.

        \sa ExposureTimeMode AnalogueGainMode

  - AeState:
      type: int32_t
      direction: out
      description: |
        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.

        \sa AnalogueGainMode
        \sa ExposureTimeMode

      enum:
        - name: AeStateIdle
          value: 0
          description: |
            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.
        - name: AeStateSearching
          value: 1
          description: |
            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.
        - name: AeStateConverged
          value: 2
          description: |
            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.

  # AeMeteringMode needs further attention:
  # - Auto-generate max enum value.
  # - Better handling of custom types.
  - AeMeteringMode:
      type: int32_t
      direction: inout
      description: |
        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.
      enum:
        - name: MeteringCentreWeighted
          value: 0
          description: Centre-weighted metering mode.
        - name: MeteringSpot
          value: 1
          description: Spot metering mode.
        - name: MeteringMatrix
          value: 2
          description: Matrix metering mode.
        - name: MeteringCustom
          value: 3
          description: Custom metering mode.

  # AeConstraintMode needs further attention:
  # - Auto-generate max enum value.
  # - Better handling of custom types.
  - AeConstraintMode:
      type: int32_t
      direction: inout
      description: |
        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.
      enum:
        - name: ConstraintNormal
          value: 0
          description: |
            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.
        - name: ConstraintHighlight
          value: 1
          description: |
            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.
        - name: ConstraintShadows
          value: 2
          description: |
            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.
        - name: ConstraintCustom
          value: 3
          description: |
            Custom constraint mode.

  # AeExposureMode needs further attention:
  # - Auto-generate max enum value.
  # - Better handling of custom types.
  - AeExposureMode:
      type: int32_t
      direction: inout
      description: |
        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.

        \sa AnalogueGainMode
        \sa ExposureTimeMode

      enum:
        - name: ExposureNormal
          value: 0
          description: Default exposure mode.
        - name: ExposureShort
          value: 1
          description: Exposure mode allowing only short exposure times.
        - name: ExposureLong
          value: 2
          description: Exposure mode allowing long exposure times.
        - name: ExposureCustom
          value: 3
          description: Custom exposure mode.

  - ExposureValue:
      type: float
      direction: inout
      description: |
        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].

        \sa AnalogueGainMode
        \sa ExposureTimeMode

  - ExposureTime:
      type: int32_t
      direction: inout
      description: |
        Exposure time for the frame applied in the sensor device.

        This value is specified in microseconds.

        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.

        \sa AnalogueGain
        \sa ExposureTimeMode

  - ExposureTimeMode:
      type: int32_t
      direction: inout
      description: |
        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.

        \par 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

        \sa ExposureTime
      enum:
        - name: ExposureTimeModeAuto
          value: 0
          description: |
            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.
        - name: ExposureTimeModeManual
          value: 1
          description: |
            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.

  - AnalogueGain:
      type: float
      direction: inout
      description: |
        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.

        \sa ExposureTime
        \sa AnalogueGainMode

  - AnalogueGainMode:
      type: int32_t
      direction: inout
      description: |
        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.

        \sa ExposureTimeMode
        \sa AnalogueGain
      enum:
        - name: AnalogueGainModeAuto
          value: 0
          description: |
            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.
        - name: AnalogueGainModeManual
          value: 1
          description: |
            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.

  - AeFlickerMode:
      type: int32_t
      direction: inout
      description: |
        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.

      enum:
        - name: FlickerOff
          value: 0
          description: |
            No flicker avoidance is performed.
        - name: FlickerManual
          value: 1
          description: |
            Manual flicker avoidance.

            Suppress flicker effects caused by lighting running with a period
            specified by the AeFlickerPeriod control.
            \sa AeFlickerPeriod
        - name: FlickerAuto
          value: 2
          description: |
            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.
            \sa AeFlickerDetected

  - AeFlickerPeriod:
      type: int32_t
      direction: inout
      description: |
        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.

        \sa AeFlickerMode

  - AeFlickerDetected:
      type: int32_t
      direction: out
      description: |
        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.

        \sa AeFlickerMode

  - Brightness:
      type: float
      direction: inout
      description: |
        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.

  - Contrast:
      type: float
      direction: inout
      description:  |
        Specify a fixed contrast parameter.

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

  - Lux:
      type: float
      direction: out
      description: |
        Report an estimate of the current illuminance level in lux.

        The Lux control can only be returned in metadata.

  - AwbEnable:
      type: bool
      direction: inout
      description: |
        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.

        \sa ColourCorrectionMatrix
        \sa ColourGains
        \sa ColourTemperature

  # AwbMode needs further attention:
  # - Auto-generate max enum value.
  # - Better handling of custom types.
  - AwbMode:
      type: int32_t
      direction: inout
      description: |
        Specify the range of illuminants to use for the AWB algorithm.

        The modes supported are platform specific, and not all modes may be
        supported.
      enum:
        - name: AwbAuto
          value: 0
          description: Search over the whole colour temperature range.
        - name: AwbIncandescent
          value: 1
          description: Incandescent AWB lamp mode.
        - name: AwbTungsten
          value: 2
          description: Tungsten AWB lamp mode.
        - name: AwbFluorescent
          value: 3
          description: Fluorescent AWB lamp mode.
        - name: AwbIndoor
          value: 4
          description: Indoor AWB lighting mode.
        - name: AwbDaylight
          value: 5
          description: Daylight AWB lighting mode.
        - name: AwbCloudy
          value: 6
          description: Cloudy AWB lighting mode.
        - name: AwbCustom
          value: 7
          description: Custom AWB mode.

  - AwbLocked:
      type: bool
      direction: out
      description: |
        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.

        \sa AwbEnable

  - ColourGains:
      type: float
      direction: inout
      description: |
        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.

        \sa AwbEnable
        \sa ColourTemperature
      size: [2]

  - ColourTemperature:
      type: int32_t
      direction: out
      description: |
        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.

        \sa AwbEnable
        \sa ColourCorrectionMatrix
        \sa ColourGains

  - Saturation:
      type: float
      direction: inout
      description:  |
        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.

  - SensorBlackLevels:
      type: int32_t
      direction: out
      description: |
        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.
      size: [4]

  - Sharpness:
      type: float
      direction: inout
      description:  |
        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.

  - FocusFoM:
      type: int32_t
      direction: out
      description: |
        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.

  - ColourCorrectionMatrix:
      type: float
      direction: inout
      description: |
        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.

        \sa AwbEnable
        \sa ColourTemperature
      size: [3,3]

  - ScalerCrop:
      type: Rectangle
      direction: inout
      description: |
        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.

  - DigitalGain:
      type: float
      direction: inout
      description: |
        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.

  - FrameDuration:
      type: int64_t
      direction: out
      description: |
        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:
      type: int64_t
      direction: inout
      description: |
        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.

        \sa AeExposureMode
        \sa 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.

      size: [2]

  - SensorTemperature:
      type: float
      direction: out
      description: |
        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:
      type: int64_t
      direction: out
      description: |
        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.

  - AfMode:
      type: int32_t
      direction: inout
      description: |
        The mode of the AF (autofocus) algorithm.

        An implementation may choose not to implement all the modes.

      enum:
        - name: AfModeManual
          value: 0
          description: |
            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.
        - name: AfModeAuto
          value: 1
          description: |
            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.
        - name: AfModeContinuous
          value: 2
          description: |
            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.

  - AfRange:
      type: int32_t
      direction: inout
      description: |
        The range of focus distances that is scanned.

        An implementation may choose not to implement all the options here.
      enum:
        - name: AfRangeNormal
          value: 0
          description: |
            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.
        - name: AfRangeMacro
          value: 1
          description: |
            Only close distances are scanned.
        - name: AfRangeFull
          value: 2
          description: |
            The full range of focus distances is scanned.

            This range is similar to AfRangeNormal but includes the very
            closest macro positions.

  - AfSpeed:
      type: int32_t
      direction: inout
      description: |
        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.
      enum:
        - name: AfSpeedNormal
          value: 0
          description: Move the lens at its usual speed.
        - name: AfSpeedFast
          value: 1
          description: Move the lens more quickly.

  - AfMetering:
      type: int32_t
      direction: inout
      description: |
        The parts of the image used by the AF algorithm to measure focus.
      enum:
        - name: AfMeteringAuto
          value: 0
          description: |
            Let the AF algorithm decide for itself where it will measure focus.
        - name: AfMeteringWindows
          value: 1
          description: |
            Use the rectangles defined by the AfWindows control to measure focus.

            If no windows are specified the behaviour is platform dependent.

  - AfWindows:
      type: Rectangle
      direction: inout
      description: |
        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.

      size: [n]

  - AfTrigger:
      type: int32_t
      direction: in
      description: |
        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.

      enum:
        - name: AfTriggerStart
          value: 0
          description: |
            Start an AF scan.

            Setting the control to AfTriggerStart is ignored if a scan is in
            progress.
        - name: AfTriggerCancel
          value: 1
          description: |
            Cancel an AF scan.

            This does not cause the lens to move anywhere else. Ignored if no
            scan is in progress.

  - AfPause:
      type: int32_t
      direction: in
      description: |
        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.

      enum:
        - name: AfPauseImmediate
          value: 0
          description: |
            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.
        - name: AfPauseDeferred
          value: 1
          description: |
            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.

        - name: AfPauseResume
          value: 2
          description: |
            Resume continuous autofocus operation.

            The algorithm starts again from exactly where it left off, and
            AfPauseState will report AfPauseStateRunning.

  - LensPosition:
      type: float
      direction: inout
      description: |
        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

        \f$LP = \frac{1\mathrm{m}}{D}\f$

        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.

  - AfState:
      type: int32_t
      direction: out
      description: |
        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.

      enum:
        - name: AfStateIdle
          value: 0
          description: |
            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.
        - name: AfStateScanning
          value: 1
          description: |
            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.
        - name: AfStateFocused
          value: 2
          description: |
            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.
        - name: AfStateFailed
          value: 3
          description: |
            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.

  - AfPauseState:
      type: int32_t
      direction: out
      description: |
        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.

      enum:
        - name: AfPauseStateRunning
          value: 0
          description: |
            Continuous AF is running and the algorithm may restart a scan
            spontaneously.
        - name: AfPauseStatePausing
          value: 1
          description: |
            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.
        - name: AfPauseStatePaused
          value: 2
          description: |
            Continuous AF is paused.

            No further state changes or lens movements will occur until the
            AfPauseResume control is sent.

  - HdrMode:
      type: int32_t
      direction: inout
      description: |
        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.

        \sa HdrChannel

      enum:
        - name: HdrModeOff
          value: 0
          description: |
            HDR is disabled.

            Metadata for this frame will not include the HdrChannel control.
        - name: HdrModeMultiExposureUnmerged
          value: 1
          description: |
            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.
        - name: HdrModeMultiExposure
          value: 2
          description: |
            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.
        - name: HdrModeSingleExposure
          value: 3
          description: |
            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.
        - name: HdrModeNight
          value: 4
          description: |
            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.

  - HdrChannel:
      type: int32_t
      direction: out
      description: |
        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.

        \sa HdrMode

      enum:
        - name: HdrChannelNone
          value: 0
          description: |
            This image does not correspond to any of the captures used to create
            an HDR image.
        - name: HdrChannelShort
          value: 1
          description: |
            This is a short exposure image.
        - name: HdrChannelMedium
          value: 2
          description: |
            This is a medium exposure image.
        - name: HdrChannelLong
          value: 3
          description: |
            This is a long exposure image.

  - Gamma:
      type: float
      direction: inout
      description:  |
        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.

  - DebugMetadataEnable:
      type: bool
      direction: inout
      description: |
        Enable or disable the debug metadata.

  - FrameWallClock:
      type: int64_t
      direction: out
      description: |
        This timestamp corresponds to the same moment in time as the
        SensorTimestamp, but is represented as a wall clock time as measured by
        the CLOCK_REALTIME clock. Like SensorTimestamp, the timestamp value is
        expressed in nanoseconds.

        Being a wall clock measurement, it can be used to synchronise timing
        across different devices.

        \sa SensorTimestamp

        The FrameWallClock control can only be returned in metadata.

...
