libcamera::ipa::AgcAlgorithm Class Reference

libIPA LSC algorithm algorithm More...

Classes
struct	ConfigurationParams
	Parameters for AgcAlgorithm::configure() More...
struct	ProcessParams
	Parameters for AgcAlgorithm::process() More...

Public Member Functions
int	init (const ValueNode &tuningData, CameraSensorHelper *sensor, const ConfigurationParams &config)
	Load tuning data and configure.
int	configure (agc::Session &session, agc::ActiveState &state, const ConfigurationParams &config)
	Initialize the session configuration and active state.
void	queueRequest (const agc::Session &session, agc::ActiveState &state, agc::FrameContext &frameContext, const ControlList &controls)
	Queue a request.
void	prepare (agc::ActiveState &state, agc::FrameContext &frameContext)
	Prepare a frame.
void	process (const agc::Session &session, agc::ActiveState &state, agc::FrameContext &frameContext, std::optional< ProcessParams > &&params, ControlList &metadata)
	Process frame statistics.

Detailed Description

libIPA LSC algorithm algorithm

The AgcAlgorithm class can be used to implement automatic exposure/gain control in an IPA module, conforming to the prescribed Algorithm interface. Internally AgcMeanLuminance or AgcMSV is used, this class merely concerns itself with processing the sensor properties, establishing limits, managing controls, and providing the resulting metadata.

Users should compose agc::Session, agc::ActiveState, and agc::FrameContext into their platform-specific session configuration, active state, and frame contexts, respectively. Furthermore, in their implementation of the Algorithm virtual function, they should simply call the identically named member function of AgcAlgorithm.

Todo:

DigitalGain, DigitalGainMode

Expand documentation

Member Function Documentation

configure()

int libcamera::ipa::AgcAlgorithm::configure	(	agc::Session &	session,
		agc::ActiveState &	state,
		const ConfigurationParams &	config
	)

Initialize the session configuration and active state.

Parameters

[in]	session	The agc session configuration
[in]	state	The agc active state
[in]	config	The algorithm configuration

This function initializes session and state based on the tuning data loaded by init() and the configuration in config.

It also updates ConfigurationParams::ctrlMap with the limits of the various agc-related controls. Users are expected to propagate these controls to the camera.

Returns

0 on success, or a negative error code

See also

Algorithm::configure()

init()

int libcamera::ipa::AgcAlgorithm::init	(	const ValueNode &	tuningData,
		CameraSensorHelper *	sensor,
		const ConfigurationParams &	config
	)

Load tuning data and configure.

Parameters

[in]	tuningData	The tuning data
[in]	sensor	The camera sensor helper
[in]	config	The algorithm configuration

This function loads the tuning data and configures the algorithm as if by a call to configure(), in order to provide the available controls in ConfigurationParams::ctrlMap.

If a CameraSensorHelper is provided in sensor, an instance of AgcMeanLuminance is instantiated and the tuning data is loaded by calling AgcMeanLuminance::parseTuningData(). Otherwise an instance of AgcMSV is instantiated, and in this case the tuning data is ignored.

Returns

0 on success, or a negative error code

See also

Algorithm::init()

prepare()

void libcamera::ipa::AgcAlgorithm::prepare	(	agc::ActiveState &	state,
		agc::FrameContext &	frameContext
	)

Prepare a frame.

Parameters

[in]	state	The agc active state
[in]	frameContext	The agc frame context

This function prepares the parameters for the frame denoted by frameContext. After a call to this function, the values of frameContext.exposure and frameContext.gain will be finalized and may be used by the caller (see agc::prepareControls()).

Todo:

Finalize frameContext.vblank as well

See also

Algorithm::prepare()

process()

void libcamera::ipa::AgcAlgorithm::process	(	const agc::Session &	session,
		agc::ActiveState &	state,
		agc::FrameContext &	frameContext,
		std::optional< ProcessParams > &&	params,
		ControlList &	metadata
	)

Process frame statistics.

Parameters

[in]	session	The agc session configuration
[in]	state	The agc active state
[in]	frameContext	The agc frame context
[in]	params	The algorithm parameters
[in]	metadata	The list of metadata

This function processes the statistics for the completed frame denoted by frameContext, runs the AGC implementation, updates state appropriately, and also populates metadata for the completed frame.

params must be omitted if the session was configured without "autoAllowed", and it may be omitted even if auto control is enabled, for example, if the statistics could not be delivered due to some ephemeral error. This ensures that the algorithm state will not go out of sync, and that metadata is produced as expected.

Care must be taken to convert the platform specific statistics to the format expected in params. See ProcessParams for the details.

See also

Algorithm::process()

queueRequest()

void libcamera::ipa::AgcAlgorithm::queueRequest	(	const agc::Session &	session,
		agc::ActiveState &	state,
		agc::FrameContext &	frameContext,
		const ControlList &	controls
	)

Queue a request.

Parameters

[in]	session	The agc session configuration
[in]	state	The agc active state
[in]	frameContext	The agc frame context
[in]	controls	The list of controls associated with a Request

This functions processes the agc-related controls in controls for the frame denoted by frameContext, and updates state and frameContext accordingly.

See also

Algorithm::queueRequest()

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The documentation for this class was generated from the following files:

• src/ipa/libipa/agc.h
• src/ipa/libipa/agc.cpp