QVideoSurfaceFormat Class
The QVideoSurfaceFormat class specifies the stream format of a video presentation surface. More...
Header: | #include <QVideoSurfaceFormat> |
qmake: | QT += multimedia |
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 | isMirrored() const |
bool | isValid() const |
QSize | pixelAspectRatio() const |
QVideoFrame::PixelFormat | pixelFormat() const |
QVariant | property(const char *name) const |
QList<QByteArray> | propertyNames() const |
QVideoSurfaceFormat::Direction | scanLineDirection() const |
void | setFrameRate(qreal rate) |
void | setFrameSize(const QSize &size) |
void | setFrameSize(int width, int height) |
void | setMirrored(bool mirrored) |
void | setPixelAspectRatio(const QSize &ratio) |
void | setPixelAspectRatio(int horizontal, int vertical) |
void | setProperty(const char *name, const QVariant &value) |
void | setScanLineDirection(QVideoSurfaceFormat::Direction direction) |
void | setViewport(const QRect &viewport) |
void | setYCbCrColorSpace(QVideoSurfaceFormat::YCbCrColorSpace space) |
QSize | sizeHint() const |
QRect | viewport() const |
QVideoSurfaceFormat::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 a wider range of colors. |
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 dimensions 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 must be the same as that of the surface format.
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.
Note: 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
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.
QVideoSurfaceFormat::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::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.
Note: 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 isMirrored().
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.
Trying to set a read only property will be ignored.
See also property().
void QVideoSurfaceFormat::setScanLineDirection(QVideoSurfaceFormat::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(QVideoSurfaceFormat::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().
QVideoSurfaceFormat::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 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.
© 2021 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.