QVideoFrame 类表示视频数据帧。 更多...
| 头： | #include <QVideoFrame> |
| CMake: |
find_package(Qt6 COMPONENTS Multimedia REQUIRED)
target_link_libraries(mytarget PRIVATE Qt6::Multimedia) |
| qmake: | QT += multimedia |
| enum | HandleType { NoHandle, RhiTextureHandle } |
| enum | MapMode { NotMapped, ReadOnly, WriteOnly, ReadWrite } |
| QVideoFrame (QVideoFrame && other ) | |
| QVideoFrame (const QVideoFrame & other ) | |
| QVideoFrame (const QVideoFrameFormat & format ) | |
| QVideoFrame () | |
| QVideoFrame & | operator= (const QVideoFrame & other ) |
| QVideoFrame & | operator= (QVideoFrame && other ) |
| ~QVideoFrame () | |
| uchar * | bits (int plane ) |
| const uchar * | bits (int plane ) const |
| int | bytesPerLine (int plane ) const |
| qint64 | endTime () const |
| QVideoFrame::HandleType | handleType () const |
| int | height () const |
| bool | isMapped () const |
| bool | isReadable () const |
| bool | isValid () const |
| bool | isWritable () const |
| bool | map (QVideoFrame::MapMode mode ) |
| QVideoFrame::MapMode | mapMode () const |
| int | mappedBytes (int plane ) const |
| void | paint (QPainter * painter , const QRectF & rect , const QVideoFrame::PaintOptions & options ) |
| QVideoFrameFormat::PixelFormat | pixelFormat () const |
| int | planeCount () const |
| void | setEndTime (qint64 time ) |
| void | setStartTime (qint64 time ) |
| void | setSubtitleText (const QString & text ) |
| QSize | size () const |
| qint64 | startTime () const |
| QString | subtitleText () const |
| QVideoFrameFormat | surfaceFormat () const |
| QImage | toImage () const |
| void | unmap () |
| int | width () const |
| bool | operator!= (const QVideoFrame & other ) const |
| bool | operator== (const QVideoFrame & other ) const |
QVideoFrame 封装视频帧的像素数据，及帧有关信息。
Video frames can come from several places - decoded media ， camera , or generated programmatically. The way pixels are described in these frames can vary greatly, and some pixel formats offer greater compression opportunities at the expense of ease of use.
The pixel contents of a video frame can be mapped to memory using the map () function. After a successful call to map (), the video data can be accessed through various functions. Some of the YUV pixel formats provide the data in several planes. The planeCount () method will return the amount of planes that being used.
While mapped, the video data of each plane can accessed using the bits () function, which returns a pointer to a buffer. The size of this buffer is given by the mappedBytes () function, and the size of each line is given by bytesPerLine (). The return value of the handle() function may also be used to access frame data using the internal buffer's native APIs (for example - an OpenGL texture handle).
A video frame can also have timestamp information associated with it. These timestamps can be used to determine when to start and stop displaying the frame.
QVideoFrame objects can consume a significant amount of memory or system resources and should not be held for longer than required by the application.
注意： Since video frames can be expensive to copy, QVideoFrame is explicitly shared, so any change made to a video frame will also apply to any copies.
标识视频缓冲句柄的类型。
| 常量 | 值 | 描述 |
|---|---|---|
QVideoFrame::NoHandle
|
0
|
缓冲没有句柄，只能通过映射缓冲访问其数据。 |
QVideoFrame::RhiTextureHandle
|
1
|
The handle of the buffer is defined by The Qt Rendering Hardware Interface (RHI). RHI is Qt's internal graphics abstraction for 3D APIs, such as OpenGL, Vulkan, Metal, and Direct 3D. |
另请参阅 handleType ().
枚举如何把视频缓冲数据映射到系统内存。
| 常量 | 值 | 描述 |
|---|---|---|
QVideoFrame::NotMapped
|
0x00
|
不把视频缓冲映射到内存。 |
QVideoFrame::ReadOnly
|
0x01
|
The mapped memory is populated with data from the video buffer when mapped, but the content of the mapped memory may be discarded when unmapped. |
QVideoFrame::WriteOnly
|
0x02
|
The mapped memory is uninitialized when mapped, but the possibly modified content will be used to populate the video buffer when unmapped. |
QVideoFrame::ReadWrite
|
ReadOnly | WriteOnly
|
The mapped memory is populated with data from the video buffer, and the video buffer is repopulated with the content of the mapped memory when it is unmapped. |
Constructs a QVideoFrame by moving from other .
Constructs a shallow copy of other . Since QVideoFrame is explicitly shared, these two instances will reflect the same frame.
Constructs a video frame of the given pixel format .
构造 null 视频帧。
Assigns the contents of other to this video frame. Since QVideoFrame is explicitly shared, these two instances will reflect the same frame.
移动 other 到此 QVideoFrame .
销毁视频帧。
返回指针指向帧数据缓冲的开始为 plane .
此值才有效当帧数据为 mapped .
凭借此指针访问数据做出的改变 (当采用写入访问映射时) 只保证有持久化当 unmap () 被调用和当缓冲已被映射以供写入。
另请参阅 map (), mappedBytes (), bytesPerLine ()，和 planeCount ().
返回指针指向帧数据缓冲的开始为 plane .
此值才有效当帧数据为 mapped .
若缓冲未采用读取访问被映射，此缓冲的内容将被初始为未被初始化。
另请参阅 map (), mappedBytes (), bytesPerLine ()，和 planeCount ().
Returns the number of bytes in a scan line of a plane .
此值才有效当帧数据为 mapped .
另请参阅 bits (), map (), mappedBytes ()，和 planeCount ().
Returns the presentation time (in microseconds) when a frame should stop being displayed.
无效时间表示为 -1。
另请参阅 setEndTime ().
返回视频帧的句柄类型。
The handle type could either be NoHandle , meaning that the frame is memory based, or a RHI texture.
返回视频帧的高度。
Identifies if a video frame's contents are currently mapped to system memory.
This is a convenience function which checks that the MapMode of the frame is not equal to QVideoFrame::NotMapped .
Returns true if the contents of the video frame are mapped to system memory, and false otherwise.
另请参阅 mapMode () 和 QVideoFrame::MapMode .
Identifies if the mapped contents of a video frame were read from the frame when it was mapped.
这是方便校验函数若 MapMode 包含 QVideoFrame::WriteOnly 标志。
Returns true if the contents of the mapped memory were read from the video frame, and false otherwise.
另请参阅 mapMode () 和 QVideoFrame::MapMode .
标识视频帧是否有效。
无效帧没有关联它的视频缓冲。
返回 true 若帧有效，和 false 若帧无效。
Identifies if the mapped contents of a video frame will be persisted when the frame is unmapped.
这是方便校验函数若 MapMode 包含 QVideoFrame::WriteOnly 标志。
Returns true if the video frame will be updated when unmapped, and false otherwise.
注意： The result of altering the data of a frame that is mapped in read-only mode is undefined. Depending on the buffer implementation the changes may be persisted, or worse alter a shared buffer.
另请参阅 mapMode () 和 QVideoFrame::MapMode .
把视频帧的内容映射到系统 (CPU 可寻址) 内存。
在某些情况下，视频帧数据可能被存储在视频内存或其它不可访问内存中，因此有必要映射帧在访问像素数据之前。这可能涉及围绕内容的拷贝，因此，应避免映射和取消映射 (除非要求)。
映射
mode
指示映射内存内容是否应读取自和/或写入帧。若映射模式包括
QVideoFrame::ReadOnly
标志将采用视频帧内容填充映射内存当初始映射时。若映射模式包括
QVideoFrame::WriteOnly
标志可能将修改映射内存内容写回到帧当取消映射时。
当映射时，可以直接访问视频帧内容透过指针返回通过 bits () 函数。
当访问数据不再需要时，确保调用 unmap () 函数以释放映射内存并可能更新视频帧内容。
若视频帧已映射在只读模式下，以只读模式多次映射它 (且取消映射它相应次数) 是准许的。在所有其它情况下，有必要先取消帧映射，在映射第二次之前。
注意： 作为只读的写入映射内存是未定义的，并可能导致共享数据改变或崩溃。
返回 true 若帧被映射到内存按给定 mode 和 false 否则。
另请参阅 unmap (), mapMode ()，和 bits ().
返回将视频帧映射到系统内存中的模式。
另请参阅 map () 和 QVideoFrame::MapMode .
Returns the number of bytes occupied by plane plane of the mapped frame data.
此值才有效当帧数据为 mapped .
另请参阅 map ().
Uses a QPainter , painter , to render this QVideoFrame to rect . The PaintOptions options can be used to specify a background color and how rect should be filled with the video.
注意： that rendering will usually happen without hardware acceleration when using this method.
Returns the pixel format of this video frame.
返回视频帧中的平面数。
另请参阅 map ().
设置呈现 time (以微秒为单位) 当帧应停止显示时。
无效时间表示为 -1。
另请参阅 endTime ().
设置呈现 time (以微秒为单位) 当帧应该被初始显示时。
无效时间表示为 -1。
另请参阅 startTime ().
Sets the subtitle text that should be rendered together with this video frame to text .
另请参阅 subtitleText ().
返回视频帧尺度。
返回呈现时间 (以微秒为单位) 当帧应该被显示时。
无效时间表示为 -1。
另请参阅 setStartTime ().
Returns the subtitle text that should be rendered together with this video frame.
另请参阅 setSubtitleText ().
Returns the surface format of this video frame.
基于像素格式将当前视频帧转换成图像。
释放的内存映射通过 map () 函数。
若 MapMode 包括 QVideoFrame::WriteOnly 标志，则这会把映射内存当前内容坚持到视频帧。
unmap() 不应被调用，若 map () 函数失败。
另请参阅 map ().
返回视频帧的宽度。
返回
true
若此
QVideoFrame
and
other
不反射相同帧。
返回
true
若此
QVideoFrame
and
other
反射相同帧。
