The QVideoFrame class represents a frame of video data. 更多...
| 头： | #include <QVideoFrame> |
| qmake: | QT += multimedia |
| enum | FieldType { ProgressiveFrame, TopField, BottomField, InterlacedFrame } |
| enum | PixelFormat { Format_Invalid, Format_ARGB32, Format_ARGB32_Premultiplied, Format_RGB32, ..., Format_User } |
| QVideoFrame () | |
| QVideoFrame (QAbstractVideoBuffer * buffer , const QSize & size , PixelFormat format ) | |
| QVideoFrame (int bytes , const QSize & size , int bytesPerLine , PixelFormat format ) | |
| QVideoFrame (const QImage & image ) | |
| QVideoFrame (const QVideoFrame & other ) | |
| ~QVideoFrame () | |
| QVariantMap | availableMetaData () const |
| uchar * | bits () |
| uchar * | bits (int plane ) |
| const uchar * | bits () const |
| const uchar * | bits (int plane ) const |
| int | bytesPerLine () const |
| int | bytesPerLine (int plane ) const |
| qint64 | endTime () const |
| FieldType | fieldType () const |
| QVariant | handle () const |
| QAbstractVideoBuffer::HandleType | handleType () const |
| int | height () const |
| bool | isMapped () const |
| bool | isReadable () const |
| bool | isValid () const |
| bool | isWritable () const |
| bool | map (QAbstractVideoBuffer::MapMode mode ) |
| QAbstractVideoBuffer::MapMode | mapMode () const |
| int | mappedBytes () const |
| QVariant | metaData (const QString & key ) const |
| PixelFormat | pixelFormat () const |
| int | planeCount () const |
| void | setEndTime (qint64 time ) |
| void | setFieldType (FieldType field ) |
| void | setMetaData (const QString & key , const QVariant & value ) |
| void | setStartTime (qint64 time ) |
| QSize | size () const |
| qint64 | startTime () const |
| void | unmap () |
| int | width () const |
| bool | operator!= (const QVideoFrame & other ) const |
| QVideoFrame & | operator= (const QVideoFrame & other ) |
| bool | operator== (const QVideoFrame & other ) const |
| QImage::Format | imageFormatFromPixelFormat (PixelFormat format ) |
| PixelFormat | pixelFormatFromImageFormat (QImage::Format format ) |
The QVideoFrame class represents a frame of video data.
A QVideoFrame encapsulates the pixel data of a video frame, and information about the frame.
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. While mapped, the video data can accessed using the bits () function, which returns a pointer to a buffer. The total 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 by an implementation of QAbstractVideoSurface to determine when to start and stop displaying the frame, but not all surfaces might respect this setting.
The video pixel data in a QVideoFrame is encapsulated in a QAbstractVideoBuffer 。 QVideoFrame may be constructed from any buffer type by subclassing the QAbstractVideoBuffer 类。
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.
Specifies the field an interlaced video frame belongs to.
| 常量 | 值 | 描述 |
|---|---|---|
QVideoFrame::ProgressiveFrame
|
0
|
The frame is not interlaced. |
QVideoFrame::TopField
|
1
|
The frame contains a top field. |
QVideoFrame::BottomField
|
2
|
The frame contains a bottom field. |
QVideoFrame::InterlacedFrame
|
3
|
The frame contains a merged top and bottom field. |
枚举视频数据类型。
| 常量 | 值 | 描述 |
|---|---|---|
QVideoFrame::Format_Invalid
|
0
|
帧是无效的。 |
QVideoFrame::Format_ARGB32
|
1
|
The frame is stored using a 32-bit ARGB format (0xAARRGGBB). This is equivalent to QImage::Format_ARGB32 . |
QVideoFrame::Format_ARGB32_Premultiplied
|
2
|
The frame stored using a premultiplied 32-bit ARGB format (0xAARRGGBB). This is equivalent to QImage::Format_ARGB32_Premultiplied . |
QVideoFrame::Format_RGB32
|
3
|
The frame stored using a 32-bit RGB format (0xffRRGGBB). This is equivalent to QImage::Format_RGB32 |
QVideoFrame::Format_RGB24
|
4
|
The frame is stored using a 24-bit RGB format (8-8-8). This is equivalent to QImage::Format_RGB888 |
QVideoFrame::Format_RGB565
|
5
|
The frame is stored using a 16-bit RGB format (5-6-5). This is equivalent to QImage::Format_RGB16 . |
QVideoFrame::Format_RGB555
|
6
|
The frame is stored using a 16-bit RGB format (5-5-5). This is equivalent to QImage::Format_RGB555 . |
QVideoFrame::Format_ARGB8565_Premultiplied
|
7
|
The frame is stored using a 24-bit premultiplied ARGB format (8-5-6-5). |
QVideoFrame::Format_BGRA32
|
8
|
The frame is stored using a 32-bit BGRA format (0xBBGGRRAA). |
QVideoFrame::Format_BGRA32_Premultiplied
|
9
|
The frame is stored using a premultiplied 32bit BGRA format. |
QVideoFrame::Format_BGR32
|
10
|
The frame is stored using a 32-bit BGR format (0xBBGGRRff). |
QVideoFrame::Format_BGR24
|
11
|
The frame is stored using a 24-bit BGR format (0xBBGGRR). |
QVideoFrame::Format_BGR565
|
12
|
帧使用 16 位 BGR 格式 (5-6-5) 存储。 |
QVideoFrame::Format_BGR555
|
13
|
帧使用 16 位 BGR 格式 (5-5-5) 存储。 |
QVideoFrame::Format_BGRA5658_Premultiplied
|
14
|
The frame is stored using a 24-bit premultiplied BGRA format (5-6-5-8). |
QVideoFrame::Format_AYUV444
|
15
|
The frame is stored using a packed 32-bit AYUV format (0xAAYYUUVV). |
QVideoFrame::Format_AYUV444_Premultiplied
|
16
|
The frame is stored using a packed premultiplied 32-bit AYUV format (0xAAYYUUVV). |
QVideoFrame::Format_YUV444
|
17
|
The frame is stored using a 24-bit packed YUV format (8-8-8). |
QVideoFrame::Format_YUV420P
|
18
|
The frame is stored using an 8-bit per component planar YUV format with the U and V planes horizontally and vertically sub-sampled, i.e. the height and width of the U and V planes are half that of the Y plane. |
QVideoFrame::Format_YV12
|
19
|
The frame is stored using an 8-bit per component planar YVU format with the V and U planes horizontally and vertically sub-sampled, i.e. the height and width of the V and U planes are half that of the Y plane. |
QVideoFrame::Format_UYVY
|
20
|
The frame is stored using an 8-bit per component packed YUV format with the U and V planes horizontally sub-sampled (U-Y-V-Y), i.e. two horizontally adjacent pixels are stored as a 32-bit macropixel which has a Y value for each pixel and common U and V values. |
QVideoFrame::Format_YUYV
|
21
|
The frame is stored using an 8-bit per component packed YUV format with the U and V planes horizontally sub-sampled (Y-U-Y-V), i.e. two horizontally adjacent pixels are stored as a 32-bit macropixel which has a Y value for each pixel and common U and V values. |
QVideoFrame::Format_NV12
|
22
|
The frame is stored using an 8-bit per component semi-planar YUV format with a Y plane (Y) followed by a horizontally and vertically sub-sampled, packed UV plane (U-V). |
QVideoFrame::Format_NV21
|
23
|
The frame is stored using an 8-bit per component semi-planar YUV format with a Y plane (Y) followed by a horizontally and vertically sub-sampled, packed VU plane (V-U). |
QVideoFrame::Format_IMC1
|
24
|
The frame is stored using an 8-bit per component planar YUV format with the U and V planes horizontally and vertically sub-sampled. This is similar to the Format_YUV420P type, except that the bytes per line of the U and V planes are padded out to the same stride as the Y plane. |
QVideoFrame::Format_IMC2
|
25
|
The frame is stored using an 8-bit per component planar YUV format with the U and V planes horizontally and vertically sub-sampled. This is similar to the Format_YUV420P type, except that the lines of the U and V planes are interleaved, i.e. each line of U data is followed by a line of V data creating a single line of the same stride as the Y data. |
QVideoFrame::Format_IMC3
|
26
|
The frame is stored using an 8-bit per component planar YVU format with the V and U planes horizontally and vertically sub-sampled. This is similar to the Format_YV12 type, except that the bytes per line of the V and U planes are padded out to the same stride as the Y plane. |
QVideoFrame::Format_IMC4
|
27
|
The frame is stored using an 8-bit per component planar YVU format with the V and U planes horizontally and vertically sub-sampled. This is similar to the Format_YV12 type, except that the lines of the V and U planes are interleaved, i.e. each line of V data is followed by a line of U data creating a single line of the same stride as the Y data. |
QVideoFrame::Format_Y8
|
28
|
The frame is stored using an 8-bit greyscale format. |
QVideoFrame::Format_Y16
|
29
|
The frame is stored using a 16-bit linear greyscale format. Little endian. |
QVideoFrame::Format_Jpeg
|
30
|
The frame is stored in compressed Jpeg format. |
QVideoFrame::Format_CameraRaw
|
31
|
The frame is stored using a device specific camera raw format. |
QVideoFrame::Format_AdobeDng
|
32
|
The frame is stored using raw Adobe Digital Negative (DNG) format. |
QVideoFrame::Format_User
|
1000
|
用户定义像素格式的起始值。 |
构造 null 视频帧。
构造视频帧从 buffer with the given pixel format and size (以像素为单位)。
注意： This doesn't increment the reference count of the video buffer.
Constructs a video frame of the given pixel format and size (以像素为单位)。
The bytesPerLine (stride) is the length of each scan line in bytes, and bytes is the total number of bytes that must be allocated for the frame.
Constructs a video frame from an image .
注意： This will construct an invalid video frame if there is no frame type equivalent to the image format.
另请参阅 pixelFormatFromImageFormat ().
Constructs a shallow copy of other 。由于 QVideoFrame is explicitly shared, these two instances will reflect the same frame.
销毁视频帧。
返回关联此帧的任何额外元数据。
返回指向帧数据缓冲起始的指针。
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 ()，和 bytesPerLine ().
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。
该函数在 Qt 5.4 引入。
另请参阅 map (), mappedBytes (), bytesPerLine ()，和 planeCount ().
返回指向帧数据缓冲起始的指针。
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 ()，和 bytesPerLine ().
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。
该函数在 Qt 5.4 引入。
另请参阅 map (), mappedBytes (), bytesPerLine ()，和 planeCount ().
返回扫描行字节数。
注意： For planar formats this is the bytes per line of the first plane only. The bytes per line of subsequent planes should be calculated as per the frame 像素格式 .
此值才有效当帧数据为 mapped .
另请参阅 bits (), map ()，和 mappedBytes ().
Returns the number of bytes in a scan line of a plane .
此值才有效当帧数据为 mapped .
该函数在 Qt 5.4 引入。
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 ().
Returns the field an interlaced video frame belongs to.
If the video is not interlaced this will return WholeFrame.
另请参阅 setFieldType ().
返回视频帧缓冲的特定类型句柄。
对于 OpenGL 纹理，这将是纹理 ID。
另请参阅 QAbstractVideoBuffer::handle ().
返回视频帧的句柄类型。
返回视频帧的高度。
[static]
QImage::Format
QVideoFrame::
imageFormatFromPixelFormat
(
PixelFormat
format
)
返回图像格式等效视频帧像素 format 。若没有等效格式 QImage::Format_Invalid 被返回取而代之。
注意： 一般而言 QImage 没有 YUV 格式。
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 QAbstractVideoBuffer::NotMapped .
Returns true if the contents of the video frame are mapped to system memory, and false otherwise.
另请参阅 mapMode () 和 QAbstractVideoBuffer::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 QAbstractVideoBuffer::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 QAbstractVideoBuffer::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 QAbstractVideoBuffer::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 QAbstractVideoBuffer::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
QAbstractVideoBuffer::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
QAbstractVideoBuffer::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 QAbstractVideoBuffer::MapMode .
返回由映射帧数据所占据的字节数。
此值才有效当帧数据为 mapped .
另请参阅 map ().
返回此帧的任何元数据为给定 key .
This might include frame specific information from a camera, or subtitles from a decoded video stream.
See the documentation for the relevant video frame producer for further information about available metadata.
另请参阅 setMetaData ().
返回视频帧的颜色格式。
[static]
PixelFormat
QVideoFrame::
pixelFormatFromImageFormat
(
QImage::Format
format
)
Returns a video pixel format equivalent to an image format . If there is no equivalent format QVideoFrame::InvalidType is returned instead.
注意： 一般而言 QImage 没有 YUV 格式。
返回视频帧中的平面数。
此值才有效当帧数据为 mapped .
该函数在 Qt 5.4 引入。
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 field 属于隔行扫描视频帧。
另请参阅 fieldType ().
设置元数据为给定 key to value .
若 value is a null variant, any metadata for this key will be removed.
The producer of the video frame might use this to associate certain data with this frame, or for an intermediate processor to add information for a consumer of this frame.
另请参阅 metaData ().
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 ().
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 ().
释放的内存映射通过 map () 函数。
若 MapMode 包括 QAbstractVideoBuffer::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。
Assigns the contents of other to this video frame. Since QVideoFrame is explicitly shared, these two instances will reflect the same frame.
返回
true
若此
QVideoFrame
and
other
反射相同帧。