QVideoSurfaceFormat Class▲
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Header: QVideoSurfaceFormat
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qmake: QT += multimedia
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Group: QVideoSurfaceFormat is part of multimedia, multimedia_video
Detailed Description▲
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.
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Constant |
Value |
Description |
|---|---|---|
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QVideoSurfaceFormat::TopToBottom |
0 |
Scan lines are arranged from the top of the frame to the bottom. |
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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.
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Constant |
Value |
Description |
|---|---|---|
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QVideoSurfaceFormat::YCbCr_Undefined |
0 |
No color space is specified. |
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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. |
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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. |
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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 a wider range of colors. |
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QVideoSurfaceFormat::YCbCr_xvYCC709 |
4 |
The BT.709 color space with the value range extended to 0 to 255. |
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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▲
QSize QVideoSurfaceFormat::frameSize() const▲
Returns the dimensions of frames in a video stream.
See Also▲
See also setFrameSize(), frameWidth(), frameHeight()
int QVideoSurfaceFormat::frameWidth() const▲
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 must be the same as that of the surface format.
[since 5.11] bool QVideoSurfaceFormat::isMirrored() const▲
Returns true if the surface is mirrored around its vertical axis. This is typically needed for video frames coming from a front camera of a mobile device.
The mirroring here differs from QImage::mirrored, as a vertically mirrored QImage will be mirrored around its x-axis.
This function was introduced in Qt 5.11.
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▲
QVideoFrame::PixelFormat QVideoSurfaceFormat::pixelFormat() const▲
Returns the pixel format of frames in a video stream.
QVariant QVideoSurfaceFormat::property(const char *name) const▲
QList<QByteArray> QVideoSurfaceFormat::propertyNames() const▲
Returns a list of video format dynamic property names.
QVideoSurfaceFormat::Direction QVideoSurfaceFormat::scanLineDirection() const▲
void QVideoSurfaceFormat::setFrameRate(qreal rate)▲
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▲
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.
[since 5.11] void QVideoSurfaceFormat::setMirrored(bool mirrored)▲
Sets if the surface is mirrored around its vertical axis. This is typically needed for video frames coming from a front camera of a mobile device. Default value is false.
The mirroring here differs from QImage::mirrored, as a vertically mirrored QImage will be mirrored around its x-axis.
This function was introduced in Qt 5.11.
See Also▲
See also isMirrored()
void QVideoSurfaceFormat::setPixelAspectRatio(const QSize &ratio)▲
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.
Trying to set a read only property will be ignored.
See Also▲
See also property()
void QVideoSurfaceFormat::setScanLineDirection(QVideoSurfaceFormat::Direction direction)▲
void QVideoSurfaceFormat::setViewport(const QRect &viewport)▲
void QVideoSurfaceFormat::setYCbCrColorSpace(QVideoSurfaceFormat::YCbCrColorSpace space)▲
Sets the Y'CbCr color space of a video stream. It is only used with raw YUV frame types.
See Also▲
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▲
See also setViewport()
QVideoSurfaceFormat::YCbCrColorSpace QVideoSurfaceFormat::yCbCrColorSpace() const▲
bool QVideoSurfaceFormat::operator!=(const QVideoSurfaceFormat &other) const▲
Returns true if other is different to this video format, and false if they are the same.
QVideoSurfaceFormat &QVideoSurfaceFormat::operator=(const QVideoSurfaceFormat &other)▲
Assigns the values of other to this object.
bool QVideoSurfaceFormat::operator==(const QVideoSurfaceFormat &other) const▲
Returns true if other is the same as this video format, and false if they are different.