The V4L2 M2M converter implements the converter interface based on V4L2 M2M device. More...

Inheritance diagram for libcamera::V4L2M2MConverter:

Collaboration diagram for libcamera::V4L2M2MConverter:

Public Member Functions
	V4L2M2MConverter (MediaDevice *media)
	Construct a V4L2M2MConverter instance. More...

int	loadConfiguration ([[maybe_unused]] const std::string &filename) override

bool	isValid () const override

std::vector< PixelFormat >	formats (PixelFormat input) override

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

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

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

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

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

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

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

int	start () override
	Start the converter streaming operation. More...

void	stop () override
	Stop the converter streaming operation. More...

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

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

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

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

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

Public Member Functions inherited from libcamera::Converter
	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...

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

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

Additional Inherited Members
Public Types inherited from libcamera::Converter
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 Attributes inherited from libcamera::Converter
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 inherited from libcamera::Converter
Features	features_
	Stores the features supported by the converter.

Detailed Description

The V4L2 M2M converter implements the converter interface based on V4L2 M2M device.

Constructor & Destructor Documentation

◆ V4L2M2MConverter()

libcamera::V4L2M2MConverter::V4L2M2MConverter ( MediaDevice * media )

Construct a V4L2M2MConverter instance.

Parameters

[in] media The media device implementing the converter

Member Function Documentation

◆ adjustInputSize()

Size libcamera::V4L2M2MConverter::adjustInputSize	(	const PixelFormat &	pixFmt,
		const Size &	size,
		Alignment	align = `Alignment::Down`
	)

overridevirtual

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

Implements libcamera::Converter.

◆ adjustOutputSize()

Size libcamera::V4L2M2MConverter::adjustOutputSize	(	const PixelFormat &	pixFmt,
		const Size &	size,
		Alignment	align = `Alignment::Down`
	)

overridevirtual

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

Implements libcamera::Converter.

◆ configure()

int libcamera::V4L2M2MConverter::configure	(	const StreamConfiguration &	inputCfg,
		const std::vector< std::reference_wrapper< StreamConfiguration >> &	outputCfgs
	)

overridevirtual

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

Implements libcamera::Converter.

◆ exportBuffers()

int libcamera::V4L2M2MConverter::exportBuffers	(	const Stream *	stream,
		unsigned int	count,
		std::vector< std::unique_ptr< FrameBuffer >> *	buffers
	)

overridevirtual

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

Implements libcamera::Converter.

◆ formats()

std::vector< PixelFormat > libcamera::V4L2M2MConverter::formats ( PixelFormat input )

overridevirtual

Parameters

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

Returns: The list of supported output pixel formats

Implements libcamera::Converter.

◆ inputCropBounds() [1/2]

libcamera::V4L2M2MConverter::inputCropBounds ( )

inlineoverridevirtual

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

Implements libcamera::Converter.

◆ inputCropBounds() [2/2]

std::pair< Rectangle, Rectangle > libcamera::V4L2M2MConverter::inputCropBounds ( const Stream * stream )

overridevirtual

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

Implements libcamera::Converter.

◆ isConfigured()

bool libcamera::V4L2M2MConverter::isConfigured ( const Stream * stream ) const

overridevirtual

Check if a given stream is configured.

Parameters

[in] stream The output stream

Returns: True if the stream is configured or false otherwise

Implements libcamera::Converter.

◆ isValid()

libcamera::V4L2M2MConverter::isValid ( ) const

inlineoverridevirtual

Returns: True is the converter is valid, false otherwise

Implements libcamera::Converter.

◆ loadConfiguration()

libcamera::V4L2M2MConverter::loadConfiguration ( [[maybe_unused] ] const std::string & filename )

inlineoverride

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()

int libcamera::V4L2M2MConverter::queueBuffers	(	FrameBuffer *	input,
		const std::map< const Stream , FrameBuffer > &	outputs
	)

overridevirtual

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

Implements libcamera::Converter.

◆ setInputCrop()

int libcamera::V4L2M2MConverter::setInputCrop	(	const Stream *	stream,
		Rectangle *	rect
	)

overridevirtual

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

Implements libcamera::Converter.

◆ sizes()

SizeRange libcamera::V4L2M2MConverter::sizes ( const Size & input )

overridevirtual

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

Implements libcamera::Converter.

◆ start()

int libcamera::V4L2M2MConverter::start ( )

overridevirtual

Start the converter streaming operation.

Returns: 0 on success or a negative error code otherwise

Implements libcamera::Converter.

◆ stop()

void libcamera::V4L2M2MConverter::stop ( )

overridevirtual

Stop the converter streaming operation.

Implements libcamera::Converter.

◆ strideAndFrameSize()

std::tuple< unsigned int, unsigned int > libcamera::V4L2M2MConverter::strideAndFrameSize	(	const PixelFormat &	pixelFormat,
		const Size &	size
	)

overridevirtual

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

Implements libcamera::Converter.

◆ validateOutput()

int libcamera::V4L2M2MConverter::validateOutput	(	StreamConfiguration *	cfg,
		bool *	adjusted,
		Alignment	align = `Alignment::Down`
	)

overridevirtual

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

Implements libcamera::Converter.

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

include/libcamera/internal/converter/converter_v4l2_m2m.h
src/libcamera/converter/converter_v4l2_m2m.cpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ V4L2M2MConverter()

Member Function Documentation

◆ adjustInputSize()

◆ adjustOutputSize()

◆ configure()

◆ exportBuffers()

◆ formats()

◆ inputCropBounds() [1/2]

◆ inputCropBounds() [2/2]

◆ isConfigured()

◆ isValid()

◆ loadConfiguration()

◆ queueBuffers()

◆ setInputCrop()

◆ sizes()

◆ start()

◆ stop()

◆ strideAndFrameSize()

◆ validateOutput()