Qt 5.9 | Qt Multimedia | C++ Classes | QVideoSurfaceFormat

Qt 5.9.4 Reference Documentation

# QVideoSurfaceFormat Class

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

Header: | #include <QVideoSurfaceFormat>
qmake: | QT += multimedia

- List of all members, including inherited members

## 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 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::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.

Trying to set a read only property will be ignored.

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 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.