[libcamera-devel] [PATCH v4 2/2] ipa: rpi: common: Handle AEC/AGC flicker controls

[Jacopo Mondi]

Hi David

On Thu, Jul 13, 2023 at 04:12:18PM +0100, David Plowman via libcamera-devel wrote:
> We handle the flicker modes by passing the correct period to the
> AEC/AGC algorithm which already contains the necessary code.
>
> The "Auto" mode, as well as reporting the detected flicker period via

If so you shouldn't register

	{ &controls::AeFlickerMode, ControlInfo(controls::AeFlickerModeValues) },

otherwise AeFlickerMode::FlickerAuto will be exposed to applications ?


> the "AeFlickerDetected" metadata, are unsupported for now.
>
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> ---
>  src/ipa/rpi/common/ipa_base.cpp | 64 ++++++++++++++++++++++++++++++++-
>  src/ipa/rpi/common/ipa_base.h   |  6 ++++
>  2 files changed, 69 insertions(+), 1 deletion(-)
>
> diff --git a/src/ipa/rpi/common/ipa_base.cpp b/src/ipa/rpi/common/ipa_base.cpp
> index f40f2e71..81d65ea5 100644
> --- a/src/ipa/rpi/common/ipa_base.cpp
> +++ b/src/ipa/rpi/common/ipa_base.cpp
> @@ -61,6 +61,8 @@ const ControlInfoMap::Map ipaControls{
>  	{ &controls::AeConstraintMode, ControlInfo(controls::AeConstraintModeValues) },
>  	{ &controls::AeExposureMode, ControlInfo(controls::AeExposureModeValues) },
>  	{ &controls::ExposureValue, ControlInfo(-8.0f, 8.0f, 0.0f) },
> +	{ &controls::AeFlickerMode, ControlInfo(controls::AeFlickerModeValues) },
> +	{ &controls::AeFlickerCustom, ControlInfo(100, 1000000) },
>  	{ &controls::Brightness, ControlInfo(-1.0f, 1.0f, 0.0f) },
>  	{ &controls::Contrast, ControlInfo(0.0f, 32.0f, 1.0f) },
>  	{ &controls::Sharpness, ControlInfo(0.0f, 16.0f, 1.0f) },
> @@ -97,7 +99,7 @@ namespace ipa::RPi {
>
>  IpaBase::IpaBase()
>  	: controller_(), frameCount_(0), mistrustCount_(0), lastRunTimestamp_(0),
> -	  firstStart_(true)
> +	  firstStart_(true), flickerState_({ 0, 0s })
>  {
>  }
>
> @@ -812,6 +814,66 @@ void IpaBase::applyControls(const ControlList &controls)
>  			break;
>  		}
>
> +		case controls::AE_FLICKER_MODE: {
> +			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
> +				controller_.getAlgorithm("agc"));
> +			if (!agc) {
> +				LOG(IPARPI, Warning)
> +					<< "Could not set AeFlickerMode - no AGC algorithm";
> +				break;
> +			}
> +
> +			int32_t mode = ctrl.second.get<int32_t>();
> +			bool modeValid = true;
> +
> +			switch (mode) {
> +			case controls::FlickerOff: {
> +				agc->setFlickerPeriod(0us);
> +
> +				break;
> +			}

Do you need braces ?

> +
> +			case controls::FlickerCustom: {
> +				agc->setFlickerPeriod(flickerState_.customPeriod);
> +
> +				break;
> +			}
> +
> +			default:
> +				LOG(IPARPI, Error) << "Flicker mode " << mode << " is not supported";
> +				modeValid = false;
> +
> +				break;
> +			}
> +
> +			if (modeValid)
> +				flickerState_.mode = mode;
> +
> +			break;
> +		}
> +
> +		case controls::AE_FLICKER_CUSTOM: {
> +			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
> +				controller_.getAlgorithm("agc"));
> +			if (!agc) {
> +				LOG(IPARPI, Warning)
> +					<< "Could not set AeFlickerCustom - no AGC algorithm";
> +				break;
> +			}
> +
> +			uint32_t customPeriod = ctrl.second.get<int32_t>();
> +			flickerState_.customPeriod = customPeriod * 1.0us;
> +
> +			/*
> +			 * We note that it makes no difference if the mode gets set to "custom"
> +			 * first, and the period updated after, or vice versa.
> +			 */

True, but what if the app never provides a value for
controls::AE_FLICKER_CUSTOM ? Should you initialize customPeriod to
some sensible default ?

> +			if (flickerState_.mode == controls::FlickerCustom)
> +				agc->setFlickerPeriod(flickerState_.customPeriod);
> +
> +			break;
> +		}
> +
>  		case controls::AWB_ENABLE: {
>  			/* Silently ignore this control for a mono sensor. */
>  			if (monoSensor_)
> diff --git a/src/ipa/rpi/common/ipa_base.h b/src/ipa/rpi/common/ipa_base.h
> index 39d00760..22823176 100644
> --- a/src/ipa/rpi/common/ipa_base.h
> +++ b/src/ipa/rpi/common/ipa_base.h
> @@ -116,6 +116,12 @@ private:
>  	/* Frame duration (1/fps) limits. */
>  	utils::Duration minFrameDuration_;
>  	utils::Duration maxFrameDuration_;
> +
> +	/* The current state of flicker avoidance. */
> +	struct FlickerState {
> +		int32_t mode;
> +		utils::Duration customPeriod;
> +	} flickerState_;
>  };
>
>  } /* namespace ipa::RPi */
> --
> 2.30.2
>