The QAbstractVideoSurface class is a base class for video presentation surfaces. More...

Inheritance diagram for QAbstractVideoSurface:

Public Types
enum	Error

Public Signals
void	activeChanged (bool active)

void	nativeResolutionChanged (const QSize &resolution)

void	supportedFormatsChanged ()

void	surfaceFormatChanged (const QVideoSurfaceFormat &format)

Public Signals inherited from QObject
void	destroyed (QObject *obj=nullptr)

void	objectNameChanged (const QString &objectName)

Public Methods
	QAbstractVideoSurface (QObject *parent=nullptr)

	~QAbstractVideoSurface ()

Error	error () const

bool	isActive () const

virtual bool	isFormatSupported (const QVideoSurfaceFormat &format) const

QSize	nativeResolution () const

virtual QVideoSurfaceFormat	nearestFormat (const QVideoSurfaceFormat &format) const

virtual bool	present (const QVideoFrame &frame) = 0

virtual bool	start (const QVideoSurfaceFormat &format)

virtual void	stop ()

virtual QList< QVideoFrame::PixelFormat >	supportedPixelFormats (QAbstractVideoBuffer::HandleType handleType=QAbstractVideoBuffer::NoHandle) const = 0

QVideoSurfaceFormat	surfaceFormat () const

Public Methods inherited from QObject
	QObject (QObject *parent=nullptr)

	~QObject ()

bool	blockSignals (bool block)

const QList< QObject * > &	children () const

bool	connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QString >	dynamicPropertyNames () const

virtual bool	event (QEvent *event)

virtual bool	eventFilter (QObject watched, QEvent event)

template<typename T >
T	findChild (const QString &childName=QString ()) const

template<class T >
QList< T >	findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<class T >
QList< T >	findChildren (const QString &childName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

bool	inherits (const QString &className) const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const

bool	isWindowType () const

void	killTimer (int id)

const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

QString	objectName () const

QObject *	parent () const

template<class T = QVariant>
T	property (const QString &name) const

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const QString &name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

QThread *	thread () const

Protected Methods
void	setError (Error error)

void	setNativeResolution (const QSize &resolution)

Protected Methods inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signalMethod) const

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signalMethod) const

bool	isSignalConnected (const QMetaMethod &signalMethod) const

int	receivers (const QString &signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Properties
	nativeResolution

Properties inherited from QObject
	objectName

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()

Static Public Methods inherited from QObject
static bool	connect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

static bool	connect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())

static bool	connect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, std::nullptr_t, const QObject receiver, std::nullptr_t)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...))

template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)

static QMetaObject &	staticMetaObject ()

static QString	tr (const char text, const char comment=nullptr, std::optional< int > numArg=std::optional< int >())

Related Functions inherited from QObject
T	qobject_cast (QObject *object)

	QObjectList

Detailed Description

The QAbstractVideoSurface class is a base class for video presentation surfaces.

The QAbstractVideoSurface class defines the standard interface that video producers use to inter-operate with video presentation surfaces. It is not supposed to be instantiated directly. Instead, you should subclass it to create new video surfaces.

A video surface presents a continuous stream of identically formatted frames, where the format of each frame is compatible with a stream format supplied when starting a presentation.

A list of pixel formats a surface can present is given by the supportedPixelFormats() function, and the isFormatSupported() function will test if a video surface format is supported. If a format is not supported the nearestFormat() function may be able to suggest a similar format. For example if a surface supports fixed set of resolutions it may suggest the smallest supported resolution that contains the proposed resolution.

The start() function takes a supported format and enables a video surface. Once started a surface will begin displaying the frames it receives in the present() function. Surfaces may hold a reference to the buffer of a presented video frame until a new frame is presented or streaming is stopped. The stop() function will disable a surface and a release any video buffers it holds references to.

See also: isActive(), start(), stop()

Member Enumeration Documentation

enum QAbstractVideoSurface::Error

This enum describes the errors that may be returned by the error() function.

Constant	Value	Description
`QAbstractVideoSurface::NoError`	`0`	No error occurred.
`QAbstractVideoSurface::UnsupportedFormatError`	`1`	A video format was not supported.
`QAbstractVideoSurface::IncorrectFormatError`	`2`	A video frame was not compatible with the format of the surface.
`QAbstractVideoSurface::StoppedError`	`3`	The surface has not been started.
`QAbstractVideoSurface::ResourceError`	`4`	The surface could not allocate some resource.

Constructor & Destructor Documentation

QAbstractVideoSurface::QAbstractVideoSurface ( QObject * parent = nullptr )

explicit

Constructs a video surface with the given parent.

QAbstractVideoSurface::~QAbstractVideoSurface ( )

Destroys this video surface.

Method Documentation

void QAbstractVideoSurface::activeChanged ( bool active )

signal

Signals the active state of a video surface has changed.

See also: isActive(), start(), stop()

Error QAbstractVideoSurface::error ( ) const

Returns the last error that occurred. If a surface fails to start(), or stops unexpectedly this function can be called to discover what error occurred.

See also: setError()

bool QAbstractVideoSurface::isActive ( ) const

Indicates whether a video surface has been started. Returns true if the surface has been started, and false otherwise.

bool QAbstractVideoSurface::isFormatSupported ( const QVideoSurfaceFormat & format ) const

virtual

Tests a video surface format to determine if a surface can accept it.

Returns true if the format is supported by the surface, and false otherwise.

QSize QAbstractVideoSurface::nativeResolution ( ) const

Returns the property containing the native resolution of video surface.

void QAbstractVideoSurface::nativeResolutionChanged ( const QSize & resolution )

signal

Signals the native resolution of video surface has changed.

QVideoSurfaceFormat QAbstractVideoSurface::nearestFormat ( const QVideoSurfaceFormat & format ) const

virtual

Returns a supported video surface format that is similar to format.

A similar surface format is one that has the same pixel format and handle type but differs in some of the other properties. For example if there are restrictions on the frame sizes a video surface can accept it may suggest a format with a larger frame size and a viewport the size of the original frame size.

If the format is already supported it will be returned unchanged, or if there is no similar supported format an invalid format will be returned.

bool QAbstractVideoSurface::present ( const QVideoFrame & frame )

pure virtual

Presents a video frame. Returns true if the frame was presented, and false if an error occurred.

Not all surfaces will block until the presentation of a frame has completed. Calling present() on a non-blocking surface may fail if called before the presentation of a previous frame has completed. In such cases the surface may not return to a ready state until it is had an opportunity to process events.

If this method fails for any other reason the surface will immediately enter the stopped state and an error() value will be set. A video surface must be in the started state for this method to succeed, and the format of the video frame must be compatible with the current video surface format.

See also: error()

void QAbstractVideoSurface::setError ( Error error )

protected

Sets the value of error() to error.

See also: error()

void QAbstractVideoSurface::setNativeResolution ( const QSize & resolution )

protected

Sets the resolution property of the video surface to resolution.

bool QAbstractVideoSurface::start ( const QVideoSurfaceFormat & format )

virtual

Starts a video surface presenting format frames. Returns true if the surface was started, and false if an error occurred.

See also: isActive(), stop()

void QAbstractVideoSurface::stop ( )

virtual

Stops a video surface presenting frames and releases any resources acquired in start().

See also: isActive(), start()

void QAbstractVideoSurface::supportedFormatsChanged ( )

signal

Signals the set of formats supported by a video surface has changed.

See also: supportedPixelFormats(), isFormatSupported()

QList< QVideoFrame::PixelFormat > QAbstractVideoSurface::supportedPixelFormats ( QAbstractVideoBuffer::HandleType handleType = QAbstractVideoBuffer::NoHandle ) const

pure virtual

Returns a list of pixel formats a video surface can present for a given handleType.

The pixel formats returned for the QAbstractVideoBuffer::NoHandle type are valid for any buffer that can be mapped in read-only mode. Types that are first in the list can be assumed to be faster to render.

QVideoSurfaceFormat QAbstractVideoSurface::surfaceFormat ( ) const

Returns the format of a video surface.

void QAbstractVideoSurface::surfaceFormatChanged ( const QVideoSurfaceFormat & format )

signal

Signals the configured format of a video surface has changed.

See also: surfaceFormat(), start()

Property Documentation

QAbstractVideoSurface::nativeResolution

The native resolution of this video surface. This is the resolution of video frames the surface can render with optimal quality and/or performance. The native resolution is not always known and can be changed during playback.

Properties	Class Methods
read	nativeResolution
notify	nativeResolutionChanged

Public Types

Public Signals

Public Methods

Protected Methods

Properties

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Method Documentation

Property Documentation