Abstract Base Class for converter. More...

Inheritance diagram for libcamera::Converter:

Collaboration diagram for libcamera::Converter:

Public Types
enum	Feature { None = 0, InputCrop = (1 << 0) }
	Specify the features supported by the converter.

enum	Alignment { Down = 0, Up }
	The alignment mode specified when adjusting the converter input or output sizes.

using	Features = Flags< Feature >
	A bitwise combination of features supported by the converter.

Public Member Functions
	Converter (MediaDevice *media, Features features=Feature::None)
	Construct a Converter instance. More...

virtual int	loadConfiguration (const std::string &filename)=0
	Load converter configuration from file. More...

virtual bool	isValid () const =0
	Check if the converter configuration is valid. More...

virtual std::vector< PixelFormat >	formats (PixelFormat input)=0
	Retrieve the list of supported pixel formats for an input pixel format. More...

virtual SizeRange	sizes (const Size &input)=0
	Retrieve the range of minimum and maximum output sizes for an input size. More...

virtual Size	adjustInputSize (const PixelFormat &pixFmt, const Size &size, Alignment align=Alignment::Down)=0
	Adjust the converter input size to a valid value. More...

virtual Size	adjustOutputSize (const PixelFormat &pixFmt, const Size &size, Alignment align=Alignment::Down)=0
	Adjust the converter output size to a valid value. More...

virtual std::tuple< unsigned int, unsigned int >	strideAndFrameSize (const PixelFormat &pixelFormat, const Size &size)=0
	Retrieve the output stride and frame size for an input configutation. More...

virtual int	validateOutput (StreamConfiguration cfg, bool adjusted, Alignment align=Alignment::Down)=0
	Validate and possibily adjust cfg to a valid converter output. More...

virtual int	configure (const StreamConfiguration &inputCfg, const std::vector< std::reference_wrapper< StreamConfiguration >> &outputCfgs)=0
	Configure a set of output stream conversion from an input stream. More...

virtual bool	isConfigured (const Stream *stream) const =0
	Check if a given stream is configured. More...

virtual int	exportBuffers (const Stream stream, unsigned int count, std::vector< std::unique_ptr< FrameBuffer >> buffers)=0
	Export buffers from the converter device. More...

virtual int	start ()=0
	Start the converter streaming operation. More...

virtual void	stop ()=0
	Stop the converter streaming operation.

virtual int	queueBuffers (FrameBuffer input, const std::map< const Stream , FrameBuffer *> &outputs)=0
	Queue buffers to converter device. More...

virtual int	setInputCrop (const Stream stream, Rectangle rect)=0
	Set the crop rectangle rect for stream. More...

virtual std::pair< Rectangle, Rectangle >	inputCropBounds ()=0
	Retrieve the crop bounds of the converter. More...

virtual std::pair< Rectangle, Rectangle >	inputCropBounds (const Stream *stream)=0
	Retrieve the crop bounds for stream. More...

const std::string &	deviceNode () const
	The converter device node attribute accessor. More...

Features	features () const
	Retrieve the features supported by the converter. More...

Public Attributes
Signal< FrameBuffer * >	inputBufferReady
	A signal emitted when the input frame buffer completes.

Signal< FrameBuffer * >	outputBufferReady
	A signal emitted on each frame buffer completion of the output queue.

Protected Attributes
Features	features_
	Stores the features supported by the converter.

Detailed Description

Abstract Base Class for converter.

The Converter class is an Abstract Base Class defining the interfaces of converter implementations.

Converters offer scaling and pixel format conversion services on an input stream. The converter can output multiple streams with individual conversion parameters from the same input stream.

Constructor & Destructor Documentation

◆ Converter()

libcamera::Converter::Converter	(	MediaDevice *	media,
		Features	features = `Feature::None`
	)

Construct a Converter instance.

Parameters

[in]	media	The media device implementing the converter
[in]	features	Features flags representing supported features

This searches for the entity implementing the data streaming function in the media graph entities and use its device node as the converter device node.

Member Function Documentation

◆ adjustInputSize()

libcamera::Converter::adjustInputSize	(	const PixelFormat &	pixFmt,
		const Size &	size,
		Alignment	align = `Alignment::Down`
	)

pure virtual

Adjust the converter input size to a valid value.

Parameters

[in]	pixFmt	The pixel format of the converter input stream
[in]	size	The converter input size to adjust to a valid value
[in]	align	The desired alignment

Returns: The adjusted converter input size or a null Size if size cannot be adjusted

Implemented in libcamera::V4L2M2MConverter.

◆ adjustOutputSize()

libcamera::Converter::adjustOutputSize	(	const PixelFormat &	pixFmt,
		const Size &	size,
		Alignment	align = `Alignment::Down`
	)

pure virtual

Adjust the converter output size to a valid value.

Parameters

[in]	pixFmt	The pixel format of the converter output stream
[in]	size	The converter output size to adjust to a valid value
[in]	align	The desired alignment

Returns: The adjusted converter output size or a null Size if size cannot be adjusted

Implemented in libcamera::V4L2M2MConverter.

◆ configure()

libcamera::Converter::configure	(	const StreamConfiguration &	inputCfg,
		const std::vector< std::reference_wrapper< StreamConfiguration >> &	outputCfgs
	)

pure virtual

Configure a set of output stream conversion from an input stream.

Parameters

[in]	inputCfg	Input stream configuration
[out]	outputCfgs	A list of output stream configurations

Returns: 0 on success or a negative error code otherwise

Implemented in libcamera::V4L2M2MConverter.

◆ deviceNode()

libcamera::Converter::deviceNode ( ) const

inline

The converter device node attribute accessor.

Returns: The converter device node string

◆ exportBuffers()

libcamera::Converter::exportBuffers	(	const Stream *	stream,
		unsigned int	count,
		std::vector< std::unique_ptr< FrameBuffer >> *	buffers
	)

pure virtual

Export buffers from the converter device.

Parameters

[in]	stream	Output stream pointer exporting the buffers
[in]	count	Number of buffers to allocate
[out]	buffers	Vector to store allocated buffers

This function operates similarly to V4L2VideoDevice::exportBuffers() on the output stream indicated by the output.

Returns: The number of allocated buffers on success or a negative error code otherwise

Implemented in libcamera::V4L2M2MConverter.

◆ features()

libcamera::Converter::features ( ) const

inline

Retrieve the features supported by the converter.

Returns: The converter Features flags

◆ formats()

libcamera::Converter::formats ( PixelFormat input )

pure virtual

Retrieve the list of supported pixel formats for an input pixel format.

Parameters

[in] input Input pixel format to retrieve output pixel format list for

Returns: The list of supported output pixel formats

Implemented in libcamera::V4L2M2MConverter.

◆ inputCropBounds() [1/2]

libcamera::Converter::inputCropBounds ( )

pure virtual

Retrieve the crop bounds of the converter.

Retrieve the minimum and maximum crop bounds of the converter. This can be used to query the crop bounds before configuring a stream.

Returns: A pair containing the minimum and maximum crop bound in that order

Implemented in libcamera::V4L2M2MConverter.

◆ inputCropBounds() [2/2]

libcamera::Converter::inputCropBounds ( const Stream * stream )

pure virtual

Retrieve the crop bounds for stream.

Parameters

[in] stream The output stream

Retrieve the minimum and maximum crop bounds for stream. The converter should support cropping (Feature::InputCrop).

The crop bounds depend on the configuration of the output stream and hence this function should be called after the stream has been configured using configure().

When called with an unconfigured stream, this function returns a pair of null rectangles.

Returns: A pair containing the minimum and maximum crop bound in that order

Implemented in libcamera::V4L2M2MConverter.

◆ isConfigured()

libcamera::Converter::isConfigured ( const Stream * stream ) const

pure virtual

Check if a given stream is configured.

Parameters

[in] stream The output stream

Returns: True if the stream is configured or false otherwise

Implemented in libcamera::V4L2M2MConverter.

◆ isValid()

libcamera::Converter::isValid ( ) const

pure virtual

Check if the converter configuration is valid.

Returns: True is the converter is valid, false otherwise

Implemented in libcamera::V4L2M2MConverter.

◆ loadConfiguration()

libcamera::Converter::loadConfiguration ( const std::string & filename )

pure virtual

Load converter configuration from file.

Parameters

[in] filename The file name path

Load converter dependent configuration parameters to apply on the hardware.

Returns: 0 on success or a negative error code otherwise

◆ queueBuffers()

libcamera::Converter::queueBuffers	(	FrameBuffer *	input,
		const std::map< const Stream , FrameBuffer > &	outputs
	)

pure virtual

Queue buffers to converter device.

Parameters

[in]	input	The frame buffer to apply the conversion
[out]	outputs	The container holding the output stream pointers and their respective frame buffer outputs.

This function queues the input frame buffer on the output streams of the outputs map key and retrieve the output frame buffer indicated by the buffer map value.

Returns: 0 on success or a negative error code otherwise

Implemented in libcamera::V4L2M2MConverter.

◆ setInputCrop()

libcamera::Converter::setInputCrop	(	const Stream *	stream,
		Rectangle *	rect
	)

pure virtual

Set the crop rectangle rect for stream.

Parameters

[in]	stream	The output stream
[in,out]	rect	The crop rectangle to apply and return the rectangle that is actually applied

Set the crop rectangle rect for stream provided the converter supports cropping. The converter has the Feature::InputCrop flag in this case.

The underlying hardware can adjust the rectangle supplied by the user due to hardware constraints. The caller can inspect rect to determine the actual rectangle that has been applied by the converter, after this function returns.

Returns: 0 on success or a negative error code otherwise

Implemented in libcamera::V4L2M2MConverter.

◆ sizes()

libcamera::Converter::sizes ( const Size & input )

pure virtual

Retrieve the range of minimum and maximum output sizes for an input size.

Parameters

[in] input Input stream size to retrieve range for

Returns: A range of output image sizes

Implemented in libcamera::V4L2M2MConverter.

◆ start()

libcamera::Converter::start ( )

pure virtual

Start the converter streaming operation.

Returns: 0 on success or a negative error code otherwise

Implemented in libcamera::V4L2M2MConverter.

◆ strideAndFrameSize()

libcamera::Converter::strideAndFrameSize	(	const PixelFormat &	pixelFormat,
		const Size &	size
	)

pure virtual

Retrieve the output stride and frame size for an input configutation.

Parameters

[in]	pixelFormat	Input stream pixel format
[in]	size	Input stream size

Returns: A tuple indicating the stride and frame size or an empty tuple on error

Implemented in libcamera::V4L2M2MConverter.

◆ validateOutput()

libcamera::Converter::validateOutput	(	StreamConfiguration *	cfg,
		bool *	adjusted,
		Alignment	align = `Alignment::Down`
	)

pure virtual

Validate and possibily adjust cfg to a valid converter output.

Parameters

[in,out]	cfg	The StreamConfiguration to validate and adjust
[out]	adjusted	Set to true if cfg has been adjusted
[in]	align	The desired alignment

Returns: 0 if cfg is valid or has been adjusted, a negative error code otherwise if cfg cannot be adjusted

Implemented in libcamera::V4L2M2MConverter.

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

include/libcamera/internal/converter.h
src/libcamera/converter.cpp

Public Types

Public Member Functions

Public Attributes

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Converter()

Member Function Documentation

◆ adjustInputSize()

◆ adjustOutputSize()

◆ configure()

◆ deviceNode()

◆ exportBuffers()

◆ features()

◆ formats()

◆ inputCropBounds() [1/2]

◆ inputCropBounds() [2/2]

◆ isConfigured()

◆ isValid()

◆ loadConfiguration()

◆ queueBuffers()

◆ setInputCrop()

◆ sizes()

◆ start()

◆ strideAndFrameSize()

◆ validateOutput()