QAbstractVideoBuffer Class

The QAbstractVideoBuffer class is an abstraction for video data. More...

Header:	#include <QAbstractVideoBuffer>
qmake:	QT += multimedia
Inherited By:	QAbstractPlanarVideoBuffer

List of all members, including inherited members

Public Types

enum	HandleType { NoHandle, GLTextureHandle, XvShmImageHandle, CoreImageHandle, QPixmapHandle, …, GLTextureRectangleHandle }
enum	MapMode { NotMapped, ReadOnly, WriteOnly, ReadWrite }

Detailed Description

The QVideoFrame class makes use of a QAbstractVideoBuffer internally to reference a buffer of video data. Quite often video data buffers may reside in video memory rather than system memory, and this class provides an abstraction of the location.

In addition, creating a subclass of QAbstractVideoBuffer will allow you to construct video frames from preallocated or static buffers, in cases where the QVideoFrame constructors taking a QByteArray or a QImage do not suffice. This may be necessary when implementing a new hardware accelerated video system, for example.

The contents of a buffer can be accessed by mapping the buffer to memory using the map() function, which returns a pointer to memory containing the contents of the video buffer. The memory returned by map() is released by calling the unmap() function.

The handle() of a buffer may also be used to manipulate its contents using type specific APIs. The type of a buffer's handle is given by the handleType() function.

See also QVideoFrame.

Member Type Documentation

enum QAbstractVideoBuffer::HandleType

Identifies the type of a video buffers handle.

Constant	Value	Description
`QAbstractVideoBuffer::NoHandle`	`0`	The buffer has no handle, its data can only be accessed by mapping the buffer.
`QAbstractVideoBuffer::GLTextureHandle`	`1`	The handle of the buffer is an OpenGL texture ID of an undefined and platform dependent target type.
`QAbstractVideoBuffer::XvShmImageHandle`	`2`	The handle contains pointer to shared memory XVideo image.
`QAbstractVideoBuffer::CoreImageHandle`	`3`	The handle contains pointer to macOS CIImage.
`QAbstractVideoBuffer::QPixmapHandle`	`4`	The handle of the buffer is a QPixmap.
`QAbstractVideoBuffer::EGLImageHandle`	`5`	The handle of the buffer is an EGLImageKHR.
`QAbstractVideoBuffer::UserHandle`	`1000`	Start value for user defined handle types.
`QAbstractVideoBuffer::GLTextureRectangleHandle`	`6`	The handle of the buffer is an OpenGL texture ID of target type `GL_TEXTURE_RECTANGLE`.

See also handleType().

enum QAbstractVideoBuffer::MapMode

Enumerates how a video buffer's data is mapped to system memory.

Constant	Value	Description
`QAbstractVideoBuffer::NotMapped`	`0x00`	The video buffer is not mapped to memory.
`QAbstractVideoBuffer::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.
`QAbstractVideoBuffer::WriteOnly`	`0x02`	The mapped memory is uninitialized when mapped, but the possibly modified content will be used to populate the video buffer when unmapped.
`QAbstractVideoBuffer::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.

See also mapMode() and map().