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QVideoSurfaceFormat Class Reference

The QVideoSurfaceFormat class specifies the stream format of a video presentation surface. More...

 #include <QVideoSurfaceFormat>

This class was introduced in Qt Mobility 1.0.

Public Types

enum Direction { TopToBottom, BottomToTop }
enum YCbCrColorSpace { YCbCr_Undefined, YCbCr_BT601, YCbCr_BT709, YCbCr_xvYCC601, YCbCr_xvYCC709, YCbCr_JPEG }

Public Functions

QVideoSurfaceFormat ()
QVideoSurfaceFormat ( const QSize & size, QVideoFrame::PixelFormat format, QAbstractVideoBuffer::HandleType type = QAbstractVideoBuffer::NoHandle )
QVideoSurfaceFormat ( const QVideoSurfaceFormat & other )
~QVideoSurfaceFormat ()
int frameHeight () const
qreal frameRate () const
QSize frameSize () const
int frameWidth () const
QAbstractVideoBuffer::HandleType handleType () const
bool isValid () const
QSize pixelAspectRatio () const
QVideoFrame::PixelFormat pixelFormat () const
QVariant property ( const char * name ) const
QList<QByteArray> propertyNames () const
Direction scanLineDirection () const
void setFrameRate ( qreal rate )
void setFrameSize ( const QSize & size )
void setFrameSize ( int width, int height )
void setPixelAspectRatio ( const QSize & ratio )
void setPixelAspectRatio ( int horizontal, int vertical )
void setProperty ( const char * name, const QVariant & value )
void setScanLineDirection ( Direction direction )
void setViewport ( const QRect & viewport )
void setYCbCrColorSpace ( YCbCrColorSpace space )
QSize sizeHint () const
QRect viewport () const
YCbCrColorSpace yCbCrColorSpace () const
bool operator!= ( const QVideoSurfaceFormat & other ) const
QVideoSurfaceFormat & operator= ( const QVideoSurfaceFormat & other )
bool operator== ( const QVideoSurfaceFormat & other ) const

Detailed Description

The QVideoSurfaceFormat class specifies the stream format of a video presentation surface.

A video surface presents a stream of video frames. The surface's format describes the type of the frames and determines how they should be presented.

The core properties of a video stream required to setup a video surface are the pixel format given by pixelFormat(), and the frame dimensions given by frameSize().

If the surface is to present frames using a frame's handle a surface format will also include a handle type which is given by the handleType() function.

The region of a frame that is actually displayed on a video surface is given by the viewport(). A stream may have a viewport less than the entire region of a frame to allow for videos smaller than the nearest optimal size of a video frame. For example the width of a frame may be extended so that the start of each scan line is eight byte aligned.

Other common properties are the pixelAspectRatio(), scanLineDirection(), and frameRate(). Additionally a stream may have some additional type specific properties which are listed by the dynamicPropertyNames() function and can be accessed using the property(), and setProperty() functions.

Member Type Documentation

enum QVideoSurfaceFormat::Direction

Enumerates the layout direction of video scan lines.

Constant Value Description
QVideoSurfaceFormat::TopToBottom 0 Scan lines are arranged from the top of the frame to the bottom.
QVideoSurfaceFormat::BottomToTop 1 Scan lines are arranged from the bottom of the frame to the top.

enum QVideoSurfaceFormat::YCbCrColorSpace

Enumerates the Y'CbCr color space of video frames.

Constant Value Description
QVideoSurfaceFormat::YCbCr_Undefined 0 No color space is specified.
QVideoSurfaceFormat::YCbCr_BT601 1 A Y'CbCr color space defined by ITU-R recommendation BT.601 with Y value range from 16 to 235, and Cb/Cr range from 16 to 240. Used in standard definition video.
QVideoSurfaceFormat::YCbCr_BT709 2 A Y'CbCr color space defined by ITU-R BT.709 with the same values range as YCbCr_BT601. Used for HDTV.
QVideoSurfaceFormat::YCbCr_xvYCC601 3 The BT.601 color space with the value range extended to 0 to 255. It is backward compatibile with BT.601 and uses values outside BT.601 range to represent wider colors range.
QVideoSurfaceFormat::YCbCr_xvYCC709 4 The BT.709 color space with the value range extended to 0 to 255.
QVideoSurfaceFormat::YCbCr_JPEG 5 The full range Y'CbCr color space used in JPEG files.

Member Function Documentation

QVideoSurfaceFormat::QVideoSurfaceFormat ()

Constructs a null video stream format.

QVideoSurfaceFormat::QVideoSurfaceFormat ( const QSize & size, QVideoFrame::PixelFormat format, QAbstractVideoBuffer::HandleType type = QAbstractVideoBuffer::NoHandle )

Contructs a description of stream which receives stream of type buffers with given frame size and pixel format.

This function was introduced in Qt Mobility 1.0.

QVideoSurfaceFormat::QVideoSurfaceFormat ( const QVideoSurfaceFormat & other )

Constructs a copy of other.

This function was introduced in Qt Mobility 1.0.

QVideoSurfaceFormat::~QVideoSurfaceFormat ()

Destroys a video stream description.

int QVideoSurfaceFormat::frameHeight () const

Returns the height of frame in a video stream.

This function was introduced in Qt Mobility 1.0.

qreal QVideoSurfaceFormat::frameRate () const

Returns the frame rate of a video stream in frames per second.

This function was introduced in Qt Mobility 1.0.

See also setFrameRate().

QSize QVideoSurfaceFormat::frameSize () const

Returns the size of frames in a video stream.

This function was introduced in Qt Mobility 1.0.

See also setFrameSize(), frameWidth(), and frameHeight().

int QVideoSurfaceFormat::frameWidth () const

Returns the width of frames in a video stream.

This function was introduced in Qt Mobility 1.0.

See also frameSize() and frameHeight().

QAbstractVideoBuffer::HandleType QVideoSurfaceFormat::handleType () const

Returns the type of handle the surface uses to present the frame data.

If the handle type is QAbstractVideoBuffer::NoHandle buffers with any handle type are valid provided they can be mapped with the QAbstractVideoBuffer::ReadOnly flag. If the handleType() is not QAbstractVideoBuffer::NoHandle then the handle type of the buffer be the same as that of the surface format.

This function was introduced in Qt Mobility 1.0.

bool QVideoSurfaceFormat::isValid () const

Identifies if a video surface format has a valid pixel format and frame size.

Returns true if the format is valid, and false otherwise.

This function was introduced in Qt Mobility 1.0.

QSize QVideoSurfaceFormat::pixelAspectRatio () const

Returns a video stream's pixel aspect ratio.

This function was introduced in Qt Mobility 1.0.

See also setPixelAspectRatio().

QVideoFrame::PixelFormat QVideoSurfaceFormat::pixelFormat () const

Returns the pixel format of frames in a video stream.

This function was introduced in Qt Mobility 1.0.

QVariant QVideoSurfaceFormat::property ( const char * name ) const

Returns the value of the video format's name property.

This function was introduced in Qt Mobility 1.0.

See also setProperty().

QList<QByteArray> QVideoSurfaceFormat::propertyNames () const

Returns a list of video format dynamic property names.

This function was introduced in Qt Mobility 1.0.

Direction QVideoSurfaceFormat::scanLineDirection () const

Returns the direction of scan lines.

This function was introduced in Qt Mobility 1.0.

See also setScanLineDirection().

void QVideoSurfaceFormat::setFrameRate ( qreal rate )

Sets the frame rate of a video stream in frames per second.

This function was introduced in Qt Mobility 1.0.

See also frameRate().

void QVideoSurfaceFormat::setFrameSize ( const QSize & size )

Sets the size of frames in a video stream to size.

This will reset the viewport() to fill the entire frame.

This function was introduced in Qt Mobility 1.0.

See also frameSize().

void QVideoSurfaceFormat::setFrameSize ( int width, int height )

This is an overloaded function.

Sets the width and height of frames in a video stream.

This will reset the viewport() to fill the entire frame.

This function was introduced in Qt Mobility 1.0.

void QVideoSurfaceFormat::setPixelAspectRatio ( const QSize & ratio )

Sets a video stream's pixel aspect ratio.

This function was introduced in Qt Mobility 1.0.

See also pixelAspectRatio().

void QVideoSurfaceFormat::setPixelAspectRatio ( int horizontal, int vertical )

This is an overloaded function.

Sets the horizontal and vertical elements of a video stream's pixel aspect ratio.

This function was introduced in Qt Mobility 1.0.

void QVideoSurfaceFormat::setProperty ( const char * name, const QVariant & value )

Sets the video format's name property to value.

This function was introduced in Qt Mobility 1.0.

See also property().

void QVideoSurfaceFormat::setScanLineDirection ( Direction direction )

Sets the direction of scan lines.

This function was introduced in Qt Mobility 1.0.

See also scanLineDirection().

void QVideoSurfaceFormat::setViewport ( const QRect & viewport )

Sets the viewport of a video stream to viewport.

This function was introduced in Qt Mobility 1.0.

See also viewport().

void QVideoSurfaceFormat::setYCbCrColorSpace ( YCbCrColorSpace space )

Sets the Y'CbCr color space of a video stream. It is only used with raw YUV frame types.

This function was introduced in Qt Mobility 1.0.

See also yCbCrColorSpace().

QSize QVideoSurfaceFormat::sizeHint () const

Returns a suggested size in pixels for the video stream.

This is the size of the viewport scaled according to the pixel aspect ratio.

This function was introduced in Qt Mobility 1.0.

QRect QVideoSurfaceFormat::viewport () const

Returns the viewport of a video stream.

The viewport is the region of a video frame that is actually displayed.

By default the viewport covers an entire frame.

This function was introduced in Qt Mobility 1.0.

See also setViewport().

YCbCrColorSpace QVideoSurfaceFormat::yCbCrColorSpace () const

Returns the Y'CbCr color space of a video stream.

This function was introduced in Qt Mobility 1.0.

See also setYCbCrColorSpace().

bool QVideoSurfaceFormat::operator!= ( const QVideoSurfaceFormat & other ) const

Returns true if other is different to a video format, and false if they are the same.

This function was introduced in Qt Mobility 1.0.

QVideoSurfaceFormat & QVideoSurfaceFormat::operator= ( const QVideoSurfaceFormat & other )

Assigns the values of other to a video stream description.

This function was introduced in Qt Mobility 1.0.

bool QVideoSurfaceFormat::operator== ( const QVideoSurfaceFormat & other ) const

Returns true if other is the same as a video format, and false if they are the different.

This function was introduced in Qt Mobility 1.0.

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