The QVideoSurfaceFormat class specifies the stream format of a video presentation surface. 更多...
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 () 函数。
The region of a frame that is actually displayed on a video surface is given by the 视口 (). 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 ()，和 setProperty () 函数。
枚举视频扫描线的布局方向。
| 常量 | 值 | 描述 |
|---|---|---|
| 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. |
枚举视频帧的 Y'CbCr 颜色空间。
| 常量 | 值 | 描述 |
|---|---|---|
| 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. |
Constructs a null video stream format.
Contructs a description of stream which receives stream of type buffers with given frame size and pixel format .
构造副本为 other .
Returns the height of frame in a video stream.
Returns the frame rate of a video stream in frames per second.
另请参阅 setFrameRate ().
Returns the size of frames in a video stream.
另请参阅 setFrameSize (), frameWidth ()，和 frameHeight ().
返回视频流中帧的宽度。
另请参阅 frameSize () 和 frameHeight ().
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 采用 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.
Identifies if a video surface format has a valid pixel format and frame size.
Returns true if the format is valid, and false otherwise.
返回视频流的像素宽高比。
另请参阅 setPixelAspectRatio ().
返回视频流中帧的像素格式。
Returns the value of the video format's name 特性。
另请参阅 setProperty ().
Returns a list of video format dynamic property names.
Returns the direction of scan lines.
另请参阅 setScanLineDirection ().
Sets the frame rate of a video stream in frames per second.
另请参阅 frameRate ().
Sets the size of frames in a video stream to size .
This will reset the 视口 () to fill the entire frame.
另请参阅 frameSize ().
这是重载函数。
设置 width and height of frames in a video stream.
This will reset the 视口 () to fill the entire frame.
Sets a video stream's pixel aspect ratio .
另请参阅 pixelAspectRatio ().
这是重载函数。
设置 horizontal and vertical elements of a video stream's pixel aspect ratio.
Sets the video format's name 特性到 value .
另请参阅 property ().
设置 direction of scan lines.
另请参阅 scanLineDirection ().
Sets the viewport of a video stream to 视口 .
另请参阅 视口 ().
Sets the Y'CbCr color space of a video stream. It is only used with raw YUV frame types.
另请参阅 yCbCrColorSpace ().
Returns a suggested size in pixels for the video stream.
This is the size of the viewport scaled according to the pixel aspect ratio.
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.
另请参阅 setViewport ().
Returns the Y'CbCr color space of a video stream.
另请参阅 setYCbCrColorSpace ().
