gg::VideoSourceFactory Class Reference

This class implements the factory design pattern for creating connections to supported video sources. More...

#include <videosourcefactory.h>

Public Member Functions
virtual	~VideoSourceFactory ()
	Free all connected devices. More...
IVideoSource *	get_device (enum Device device, enum ColourSpace colour)
	Try to connect to specified device for capturing video with specified colour space. More...
void	free_device (enum Device device)
	Close connection to specified device, if existing. More...
IVideoSource *	connect_network_source (std::string address, enum ColourSpace colour)
	Open connection to network connection specified by given address. More...
IVideoSource *	create_file_reader (const std::string filepath, enum ColourSpace colour_space)
	Create a reader to read colour_space frames format from filepath. More...

Static Public Member Functions
static VideoSourceFactory &	get_instance ()
	Get reference to singleton instance of this class. More...

Protected Member Functions
	VideoSourceFactory ()
	The constructor should never be publicly called. More...
	DISALLOW_COPY_AND_ASSIGNMENT (VideoSourceFactory)

Protected Attributes
IVideoSource *	_devices [Device::COUNT]
	So that can keep track of everything opened and in use. More...
ColourSpace	_device_colours [Device::COUNT]
	At a single point in time, only one connection using only one colour space may exist. More...

Detailed Description

This class implements the factory design pattern for creating connections to supported video sources.

It ensures no duplicate connection is created to any one supported video source, and in addition takes care of properly garbage-collecting all video source connections created during the lifetime of the singleton factory.

See also

IVideoSource

Device

Constructor & Destructor Documentation

VideoSourceFactory()

gg::VideoSourceFactory::VideoSourceFactory ( )

protected

The constructor should never be publicly called.

See also

get_instance

~VideoSourceFactory()

gg::VideoSourceFactory::~VideoSourceFactory ( )

virtual

Free all connected devices.

See also

free_device

Member Function Documentation

connect_network_source()

IVideoSource * gg::VideoSourceFactory::connect_network_source	(	std::string	address,
		enum ColourSpace	colour
	)

Open connection to network connection specified by given address.

Parameters

address
colour

Returns

pointer to the created video source. The ownership of this object passes to the caller. So the caller is responsible for garbage-collecting it.

Exceptions

NetworkSourceUnavailable	if no connection can be established
VideoSourceError	if GIFT-Grab not built with options required for the passed device and colour combination OR if there was a problem constructing the requested video source

create_file_reader()

IVideoSource * gg::VideoSourceFactory::create_file_reader	(	const std::string	filepath,
		enum ColourSpace	colour_space
	)

Create a reader to read colour_space frames format from filepath.

Parameters

filepath	Attempting to open an already open video file leads to undefined behaviour. However once the returned video source used for reading the file is destroyed, it can be re-opened.
colour_space

Returns

a polymorphic video file reader. The ownership of this returned object passes to the caller. The reader behaves like other video sources as far the callback paradigm (observer pattern) is concerned. Calling the get_frame method on this object leads to undefined behaviour, and hence should be avoided. The reader keeps sending out data with all pixels black after all video frames in the opened file are exhausted.

Exceptions

VideoSourceError

with a detailed error message if opening of filepath fails for any reason

DISALLOW_COPY_AND_ASSIGNMENT()

gg::VideoSourceFactory::DISALLOW_COPY_AND_ASSIGNMENT ( VideoSourceFactory  )

protected

free_device()

void gg::VideoSourceFactory::free_device

(

enum Device

device

)

Close connection to specified device, if existing.

Parameters

device

Exceptions

DeviceNotFound

if type not recognised

See also

get_device the IVideoSource object get_device returns will be destroyed by this, and hence the previously returned pointer will become unusable

get_device()

IVideoSource * gg::VideoSourceFactory::get_device	(	enum Device	device,
		enum ColourSpace	colour
	)

Try to connect to specified device for capturing video with specified colour space.

Note that the availability of capturing video with specified colour space depends on the custom build options selected. Cf. documentation (README file) for details.

Parameters

device
colour

Returns

pointer to the device's framegrabber. Client should not delete this pointer on its own. The factory will take care of properly garbage-collecting this at the end of the factory singleton's lifetime.

Exceptions

DeviceAlreadyConnected	if device already connected (i.e. using another colour space)
DeviceNotFound	if connection attempt fails
DeviceOffline	if connection attempt OK, but device offline (i.e. getting no frames)

See also

free_device if the intention is to connect to device with another colour than the one device is currently connected to

Exceptions

VideoSourceError

if GIFT-Grab not built with options required for the passed device and colour combination OR if there was a problem constructing the requested video source

get_instance()

VideoSourceFactory & gg::VideoSourceFactory::get_instance ( )

static

Get reference to singleton instance of this class.

Returns

Member Data Documentation

_device_colours

ColourSpace gg::VideoSourceFactory::_device_colours[Device::COUNT]

protected

At a single point in time, only one connection using only one colour space may exist.

_devices

IVideoSource* gg::VideoSourceFactory::_devices[Device::COUNT]

protected

So that can keep track of everything opened and in use.

See also

Device the length of this pointer array is to be kept in sync with the number of devices supported

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

• src/api/videosourcefactory.h
• src/api/videosourcefactory.cpp