The QGStreamerVideoSource class provides a video source backed by a custom GStreamer element. More...

#include <qgstreamervideosource.h>

Inheritance diagram for QGStreamerVideoSource:

Collaboration diagram for QGStreamerVideoSource:

Public Slots
void	setActive (bool active)
void	start ()
	\qmlmethod void GStreamerVideoSource::start()
void	stop ()
	\qmlmethod void GStreamerVideoSource::stop()
Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	activeChanged (bool active)
Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.

Public Member Functions
	QGStreamerVideoSource (const QString &gstBinDescription, QObject *parent=nullptr)
	Constructs a QGStreamerVideoSource from the GStreamer bin description gstBinDescription and a parent.
	QGStreamerVideoSource (GstElement gstElement, QObject parent=nullptr)
	Constructs a QGStreamerVideoSource from an existing gstElement and a parent.
	~QGStreamerVideoSource () override
bool	isActive () const
QString	gstBinDescription () const
GstElement *	gstElement () const
	Returns the underlying `GstElement` used by the video source, or `nullptr` if the video source is non-functional.
QMediaCaptureSession *	captureSession () const
Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.
virtual	~QObject ()
	Destroys the object, deleting all its child objects.
virtual bool	event (QEvent *event)
	This virtual function receives events to an object and should return true if the event e was recognized and processed.
virtual bool	eventFilter (QObject watched, QEvent event)
	Filters events if this object has been installed as an event filter for the watched object.
QString	objectName () const
Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.
void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QBindable< QString >	bindableObjectName ()
bool	isWidgetType () const
	Returns `true` if the object is a widget; otherwise returns `false`.
bool	isWindowType () const
	Returns `true` if the object is a window; otherwise returns `false`.
bool	isQuickItemType () const
	Returns `true` if the object is a QQuickItem; otherwise returns `false`.
bool	isQmlExposed () const noexcept
	Returns whether the object has been created by the QML engine or ownership has been explicitly set via QJSEngine::setObjectOwnership().
bool	signalsBlocked () const noexcept
	Returns `true` if signals are blocked; otherwise returns `false`.
bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
QThread *	thread () const
	Returns the thread in which the object lives.
bool	moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
	Changes the thread affinity for this object and its children and returns `true` on success.
int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
int	startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
void	killTimer (int id)
	Kills the timer with timer identifier, id.
void	killTimer (Qt::TimerId id)
template<typename T>
T	findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
template<typename T>
QList< T >	findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
template<typename T>
T	findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<typename T>
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
const QObjectList &	children () const
	Returns a list of child objects.
void	setParent (QObject *parent)
	Makes the object a child of parent.
void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.
void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.
QMetaObject::Connection	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char signal=nullptr, const QObject receiver=nullptr, const char *member=nullptr) const
bool	disconnect (const QObject receiver, const char member=nullptr) const
void	dumpObjectTree () const
	Dumps a tree of children to the debug output.
void	dumpObjectInfo () const
	Dumps information about signal connections, etc.
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.
bool	setProperty (const char *name, QVariant &&value)
QVariant	property (const char *name) const
	Returns the value of the object's name property.
QList< QByteArray >	dynamicPropertyNames () const
QBindingStorage *	bindingStorage ()
const QBindingStorage *	bindingStorage () const
QObject *	parent () const
	Returns a pointer to the parent object.
bool	inherits (const char *classname) const
	Returns `true` if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns `false`.

Protected Member Functions
	QGStreamerVideoSource (QObject *parent)
Protected Member Functions inherited from QObject
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
int	senderSignalIndex () const
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.
bool	isSignalConnected (const QMetaMethod &signal) const
virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.
virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.
virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.
virtual void	connectNotify (const QMetaMethod &signal)
virtual void	disconnectNotify (const QMetaMethod &signal)
	QObject (QObjectPrivate &dd, QObject *parent=nullptr)

Properties
bool	active
	\qmlproperty bool QtMultimedia::GStreamerVideoSource::active
QString	gstBinDescription
	\qmlproperty string QtMultimedia::GStreamerVideoSource::gstBinDescription
Properties inherited from QObject
QString	objectName
	the name of this object

Friends
class	QMediaCaptureSession

Additional Inherited Members
Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe
static QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1, typename Func2>
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1, typename Func2>
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	\threadsafe
static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)
static bool	disconnect (const QMetaObject::Connection &)
	Disconnects connection and resets it to \l{QMetaObject::Connection::operator bool()}{invalid}.
static bool	disconnect (QMetaObject::Connection &)
static bool	disconnect (QMetaObject::Connection &&conn)
	Disconnect a connection.
template<typename Func1, typename Func2>
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object receiver, Func2 slot)
template<typename Func1>
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject receiver, void **zero)
Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.
template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

The QGStreamerVideoSource class provides a video source backed by a custom GStreamer element.

Since: 6.12

\inmodule QtMultimedia

Warning: The GStreamerVideoSource class offers limited compatibility guarantees. There are no source or binary compatibility guarantees for these classes, meaning the API is only guaranteed to work with the Qt version the application has been developed against. However, incompatible changes are aimed to be kept at a minimum and will only be made in minor releases. To use the class in an application, link to Qt::MultimediaPrivate (if using CMake), and include the header #include <spi/qgstreamervideosource.h>.

Construct QGStreamerVideoSource from a GStreamer bin description or from an existing GstElement and attach it to QMediaCaptureSession by \l QMediaCaptureSession::setNativeVideoSource().

For any standard case, we recommend using QCamera instead of this class, unless you need GStreamer-specific configuration to handle any custom video source.

By default, the class is available in meta-qt6 builds. In custom builds with GStreamer support, the gstreamer_qt_api feature can enable it.

QtMultimedia must be run with the gstreamer media backend for this class to work.

QMediaCaptureSession session;
QGStreamerVideoSource videoSource(QStringLiteral("videotestsrc name=testsrc"));
 
session.setNativeVideoSource(&videoSource);
videoSource.start();

See also: QMediaCaptureSession, QCamera

Definition at line 29 of file qgstreamervideosource.h.

Constructor & Destructor Documentation

◆ QGStreamerVideoSource() [1/3]

QGStreamerVideoSource::QGStreamerVideoSource	(	const QString &	gstBinDescription,
		QObject *	parent = nullptr )

explicit

Constructs a QGStreamerVideoSource from the GStreamer bin description gstBinDescription and a parent.

The GStreamer backend interprets the description and creates a bin that can act as a video source for a capture session. Use method \l gstElement() to access the created bin.

See \l{https://gstreamer.freedesktop.org/documentation/tools/gst-launch.html?gi-language=c#pipeline-description}{GStreamer documentation} for the syntax of the description string.

If it's unable to parse the specified description, preventing the GstBin from being created, the constructed QGStreamerVideoSource is non-functional, \l gstElement() returns nullptr, and \l gstBinDescription() returns an empty string.

Note: QGStreamerVideoSource doesn't perform any additional validation of the provided bin description, so if the created GstBin doesn't represent a video input for GstPipeline, QGStreamerVideoSource and the associated QMediaCaptureSession may misbehave.

For better control of the underlying GStreamer element, you can construct QGStreamerVideoSource from an existing GstElement instead.

See also: gstElement(), gstBinDescription()

Definition at line 150 of file qgstreamervideosource.cpp.

◆ QGStreamerVideoSource() [2/3]

QGStreamerVideoSource::QGStreamerVideoSource	(	GstElement *	gstElement,
		QObject *	parent = nullptr )

explicit

Constructs a QGStreamerVideoSource from an existing gstElement and a parent.

The element must provide a video source that a capture session can use. The GstElement type is forward-declared in the QGStreamerVideoSource header, so the corresponding type from the GStreamer library must be used.

If the specified element is null, the constructed video source is non-functional.

Note: The class doesn't perform any additional validation of the provided element, so if the specified element doesn't represent a video input for GstPipeline, QGStreamerVideoSource and the associated QMediaCaptureSession may misbehave.; QGStreamerVideoSource shares ownership of the provided GstElement with the caller.

Definition at line 176 of file qgstreamervideosource.cpp.

◆ ~QGStreamerVideoSource()

QGStreamerVideoSource::~QGStreamerVideoSource ( )

overridedefault

◆ QGStreamerVideoSource() [3/3]

QGStreamerVideoSource::QGStreamerVideoSource ( QObject * parent )

explicitprotected

Definition at line 183 of file qgstreamervideosource.cpp.

Member Function Documentation

◆ activeChanged

void QGStreamerVideoSource::activeChanged ( bool active )

signal

◆ captureSession()

QMediaCaptureSession * QGStreamerVideoSource::captureSession ( ) const

Definition at line 306 of file qgstreamervideosource.cpp.

◆ gstBinDescription()

QString QGStreamerVideoSource::gstBinDescription ( ) const

Definition at line 272 of file qgstreamervideosource.cpp.

◆ gstElement()

GstElement * QGStreamerVideoSource::gstElement ( ) const

Returns the underlying GstElement used by the video source, or nullptr if the video source is non-functional.

If the video source has been constructed from a GStreamer bin description, the returned GstElement is convertable to the GstBin subclass.

Note: The method does not transfer ownership of the GstElement.

Definition at line 287 of file qgstreamervideosource.cpp.

◆ isActive()

bool QGStreamerVideoSource::isActive ( ) const

Definition at line 209 of file qgstreamervideosource.cpp.

◆ setActive

void QGStreamerVideoSource::setActive ( bool active )

slot

Definition at line 293 of file qgstreamervideosource.cpp.

◆ start

void QGStreamerVideoSource::start ( )

inlineslot

\qmlmethod void GStreamerVideoSource::start()

Starts the video source.

Same as setting the \l active property to true.

Starts the video source.

Same as setting the \l active property to true.

Definition at line 47 of file qgstreamervideosource.h.

◆ stop

void QGStreamerVideoSource::stop ( )

inlineslot

\qmlmethod void GStreamerVideoSource::stop()

Stops the video source.

Same as setting the \l active property to false.

Stops the video source.

Same as setting the \l active property to false.

Definition at line 48 of file qgstreamervideosource.h.

◆ QMediaCaptureSession

friend class QMediaCaptureSession

friend

Definition at line 64 of file qgstreamervideosource.h.

Property Documentation

◆ active

bool QGStreamerVideoSource::active

readwrite

\qmlproperty bool QtMultimedia::GStreamerVideoSource::active

Describes whether the video source is currently active.

If the video source has been connected to a \l CaptureSession, this property indicates whether the underlying GstElement is attached to the GstPipeline within the media capture session.

Describes whether the video source is currently active.

If the video source has been connected to a \l QMediaCaptureSession, this property indicates whether the underlying GstElement is attached to the GstPipeline within the media capture session.

Definition at line 32 of file qgstreamervideosource.h.

◆ gstBinDescription

QString QGStreamerVideoSource::gstBinDescription

read

\qmlproperty string QtMultimedia::GStreamerVideoSource::gstBinDescription

Describes the GStreamer bin description associated with the video source.

In QML, this property is required.

The GStreamer backend interprets the description and creates a bin, that can act as a video source for a capture session.

See \l{https://gstreamer.freedesktop.org/documentation/tools/gst-launch.html?gi-language=c#pipeline-description}{GStreamer documentation} for the syntax of the description string.

If the specified description is invalid, preventing a bin from being created, the constructed GStreamerVideoSource is non-functional, and the property returns an empty string.

Note: GStreamerVideoSource doesn't perform any additional validation of the provided bin description, so if the created GstBin doesn't represent a video input for GstPipeline, GStreamerVideoSource and the associated CaptureSession may misbehave.

Describes the GStreamer bin description associated with the video source.

If the video source is non-functional or has been constructed from an existing GstElement, the property string is empty.

Definition at line 33 of file qgstreamervideosource.h.

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

qtmultimedia/src/multimedia/spi/qgstreamervideosource.h (b619c504ae2bb92af5ab50fda798c9f33ab5084d)
qtmultimedia/src/multimedia/spi/qgstreamervideosource.cpp (597e688de1bb3c313894ad9817a7b5283b195c1f)

Public Slots

Signals

Public Member Functions

Protected Member Functions

Properties

Friends

Additional Inherited Members