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QVideoSurfaceFormat Class ReferenceThe QVideoSurfaceFormat class specifies the stream format of a video presentation surface. More... #include <QVideoSurfaceFormat>This class was introduced in Qt 4.6. Public Types
Public Functions
Detailed DescriptionThe 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
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| 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.
QVideoSurfaceFormat::QVideoSurfaceFormat ( const QVideoSurfaceFormat & other )
Constructs a copy of other.
QVideoSurfaceFormat::~QVideoSurfaceFormat ()
Destroys a video stream description.
int QVideoSurfaceFormat::frameHeight () const
Returns the height of frame in a video stream.
qreal QVideoSurfaceFormat::frameRate () const
Returns the frame rate of a video stream in frames per second.
See also setFrameRate().
QSize QVideoSurfaceFormat::frameSize () const
Returns the size of frames in a video stream.
See also setFrameSize(), frameWidth(), and frameHeight().
int QVideoSurfaceFormat::frameWidth () const
Returns the width of frames in a video stream.
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.
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.
QSize QVideoSurfaceFormat::pixelAspectRatio () const
Returns a video stream's pixel aspect ratio.
See also setPixelAspectRatio().
QVideoFrame::PixelFormat QVideoSurfaceFormat::pixelFormat () const
Returns the pixel format of frames in a video stream.
QVariant QVideoSurfaceFormat::property ( const char * name ) const
Returns the value of the video format's name property.
See also setProperty().
QList<QByteArray> QVideoSurfaceFormat::propertyNames () const
Returns a list of video format dynamic property names.
Direction QVideoSurfaceFormat::scanLineDirection () const
Returns the direction of scan lines.
See also setScanLineDirection().
void QVideoSurfaceFormat::setFrameRate ( qreal rate )
Sets the frame rate of a video stream in frames per second.
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.
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.
void QVideoSurfaceFormat::setPixelAspectRatio ( const QSize & ratio )
Sets a video stream's pixel aspect ratio.
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.
void QVideoSurfaceFormat::setProperty ( const char * name, const QVariant & value )
Sets the video format's name property to value.
See also property().
void QVideoSurfaceFormat::setScanLineDirection ( Direction direction )
Sets the direction of scan lines.
See also scanLineDirection().
void QVideoSurfaceFormat::setViewport ( const QRect & viewport )
Sets the viewport of a video stream to viewport.
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.
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.
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.
See also setViewport().
YCbCrColorSpace QVideoSurfaceFormat::yCbCrColorSpace () const
Returns the Y'CbCr color space of a video stream.
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.
QVideoSurfaceFormat & QVideoSurfaceFormat::operator= ( const QVideoSurfaceFormat & other )
Assigns the values of other to a video stream description.
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.
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