QAbstractVideoSurface Class Reference

Member Function Documentation

QAbstractVideoSurface::QAbstractVideoSurface ( QObject * parent = 0 )

Constructs a video surface with the given parent.

QAbstractVideoSurface::~QAbstractVideoSurface ()

Destroys a video surface.

void QAbstractVideoSurface::activeChanged ( bool active ) [signal]

Signals that the active state of a video surface has changed.

See also isActive(), start(), and 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.

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's had an opportunity to process events.

If present() 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 present() 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().

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() and stop().

void QAbstractVideoSurface::stop () [virtual]

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

See also isActive() and start().

void QAbstractVideoSurface::supportedFormatsChanged () [signal]

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

See also supportedPixelFormats() and isFormatSupported().

QList<QVideoFrame::PixelFormat> QAbstractVideoSurface::supportedPixelFormats ( QAbstractVideoBuffer::HandleType type = QAbstractVideoBuffer::NoHandle ) const [pure virtual]

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

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 that the configured format of a video surface has changed.

See also surfaceFormat() and start().