QVideoFrame#
The QVideoFrame
class represents a frame of video data. More…
Synopsis#
Functions#
def
bytesPerLine
(plane)def
endTime
()def
handleType
()def
height
()def
isMapped
()def
isReadable
()def
isValid
()def
isWritable
()def
map
(mode)def
mapMode
()def
mappedBytes
(plane)def
mirrored
()def
__ne__
(other)def
__eq__
(other)def
pixelFormat
()def
planeCount
()def
rotationAngle
()def
setEndTime
(time)def
setMirrored
(arg__1)def
setRotationAngle
(arg__1)def
setStartTime
(time)def
setSubtitleText
(text)def
size
()def
startTime
()def
subtitleText
()def
surfaceFormat
()def
swap
(other)def
toImage
()def
unmap
()def
width
()
Note
This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE
Detailed Description#
A QVideoFrame
encapsulates the pixel data of a video frame, and information about the frame.
Video frames can come from several places - decoded media
, a 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.
Note
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.
- class PySide6.QtMultimedia.QVideoFrame#
PySide6.QtMultimedia.QVideoFrame(other)
PySide6.QtMultimedia.QVideoFrame(format)
- Parameters:
other –
PySide6.QtMultimedia.QVideoFrame
Constructs a null video frame.
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
.
- PySide6.QtMultimedia.QVideoFrame.HandleType#
Identifies the type of a video buffers handle.
Constant
Description
QVideoFrame.NoHandle
The buffer has no handle, its data can only be accessed by mapping the buffer.
QVideoFrame.RhiTextureHandle
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.
See also
- PySide6.QtMultimedia.QVideoFrame.MapMode#
Enumerates how a video buffer’s data is mapped to system memory.
Constant
Description
QVideoFrame.NotMapped
The video buffer is not mapped to memory.
QVideoFrame.ReadOnly
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
The mapped memory is uninitialized when mapped, but the possibly modified content will be used to populate the video buffer when unmapped.
QVideoFrame.ReadWrite
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.
New in version 6.1.
- PySide6.QtMultimedia.QVideoFrame.RotationAngle#
The angle of the clockwise rotation that should be applied to a video frame before displaying.
Constant
Description
QVideoFrame.Rotation0
No rotation required, the frame has correct orientation
QVideoFrame.Rotation90
The frame should be rotated by 90 degrees
QVideoFrame.Rotation180
The frame should be rotated by 180 degrees
QVideoFrame.Rotation270
The frame should be rotated by 270 degrees
New in version 6.2.3.
- PySide6.QtMultimedia.QVideoFrame.bytesPerLine(plane)#
- Parameters:
plane – int
- Return type:
int
Returns the number of bytes in a scan line of a plane
.
This value is only valid while the frame data is mapped
.
See also
bits()
map()
mappedBytes()
planeCount()
- PySide6.QtMultimedia.QVideoFrame.endTime()#
- Return type:
int
Returns the presentation time (in microseconds) when a frame should stop being displayed.
An invalid time is represented as -1.
See also
- PySide6.QtMultimedia.QVideoFrame.handleType()#
- Return type:
Returns the type of a video frame’s handle.
The handle type could either be NoHandle
, meaning that the frame is memory based, or a RHI texture.
- PySide6.QtMultimedia.QVideoFrame.height()#
- Return type:
int
Returns the height of a video frame.
- PySide6.QtMultimedia.QVideoFrame.isMapped()#
- Return type:
bool
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 NotMapped
.
Returns true if the contents of the video frame are mapped to system memory, and false otherwise.
See also
mapMode()
MapMode
- PySide6.QtMultimedia.QVideoFrame.isReadable()#
- Return type:
bool
Identifies if the mapped contents of a video frame were read from the frame when it was mapped.
This is a convenience function which checks if the MapMode
contains the WriteOnly
flag.
Returns true if the contents of the mapped memory were read from the video frame, and false otherwise.
See also
mapMode()
MapMode
- PySide6.QtMultimedia.QVideoFrame.isValid()#
- Return type:
bool
Identifies whether a video frame is valid.
An invalid frame has no video buffer associated with it.
Returns true if the frame is valid, and false if it is not.
- PySide6.QtMultimedia.QVideoFrame.isWritable()#
- Return type:
bool
Identifies if the mapped contents of a video frame will be persisted when the frame is unmapped.
This is a convenience function which checks if the MapMode
contains the WriteOnly
flag.
Returns true if the video frame will be updated when unmapped, and false otherwise.
Note
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.
See also
mapMode()
MapMode
Maps the contents of a video frame to system (CPU addressable) memory.
In some cases the video frame data might be stored in video memory or otherwise inaccessible memory, so it is necessary to map a frame before accessing the pixel data. This may involve copying the contents around, so avoid mapping and unmapping unless required.
The map mode
indicates whether the contents of the mapped memory should be read from and/or written to the frame. If the map mode includes the QVideoFrame::ReadOnly
flag the mapped memory will be populated with the content of the video frame when initially mapped. If the map mode includes the QVideoFrame::WriteOnly
flag the content of the possibly modified mapped memory will be written back to the frame when unmapped.
While mapped the contents of a video frame can be accessed directly through the pointer returned by the bits()
function.
When access to the data is no longer needed, be sure to call the unmap()
function to release the mapped memory and possibly update the video frame contents.
If the video frame has been mapped in read only mode, it is permissible to map it multiple times in read only mode (and unmap it a corresponding number of times). In all other cases it is necessary to unmap the frame first before mapping a second time.
Note
Writing to memory that is mapped as read-only is undefined, and may result in changes to shared data or crashes.
Returns true if the frame was mapped to memory in the given mode
and false otherwise.
Returns the mode a video frame was mapped to system memory in.
See also
map()
MapMode
- PySide6.QtMultimedia.QVideoFrame.mappedBytes(plane)#
- Parameters:
plane – int
- Return type:
int
Returns the number of bytes occupied by plane plane
of the mapped frame data.
This value is only valid while the frame data is mapped
.
See also
- PySide6.QtMultimedia.QVideoFrame.mirrored()#
- Return type:
bool
Returns whether the frame should be mirrored before displaying.
See also
- PySide6.QtMultimedia.QVideoFrame.__ne__(other)#
- Parameters:
other –
PySide6.QtMultimedia.QVideoFrame
- Return type:
bool
Returns true
if this QVideoFrame
and other
do not reflect the same frame.
- PySide6.QtMultimedia.QVideoFrame.__eq__(other)#
- Parameters:
other –
PySide6.QtMultimedia.QVideoFrame
- Return type:
bool
Returns true
if this QVideoFrame
and other
reflect the same frame.
- PySide6.QtMultimedia.QVideoFrame.pixelFormat()#
- Return type:
Returns the pixel format of this video frame.
- PySide6.QtMultimedia.QVideoFrame.planeCount()#
- Return type:
int
Returns the number of planes in the video frame.
See also
- PySide6.QtMultimedia.QVideoFrame.rotationAngle()#
- Return type:
Returns the angle the frame should be rotated clockwise before displaying.
See also
- PySide6.QtMultimedia.QVideoFrame.setEndTime(time)#
- Parameters:
time – int
Sets the presentation time
(in microseconds) when a frame should stop being displayed.
An invalid time is represented as -1.
See also
- PySide6.QtMultimedia.QVideoFrame.setMirrored(arg__1)#
- Parameters:
arg__1 – bool
Sets the mirrored
flag for the frame.
See also
- PySide6.QtMultimedia.QVideoFrame.setRotationAngle(arg__1)#
- Parameters:
arg__1 –
RotationAngle
Sets the angle
the frame should be rotated clockwise before displaying.
See also
- PySide6.QtMultimedia.QVideoFrame.setStartTime(time)#
- Parameters:
time – int
Sets the presentation time
(in microseconds) when the frame should initially be displayed.
An invalid time is represented as -1.
See also
- PySide6.QtMultimedia.QVideoFrame.setSubtitleText(text)#
- Parameters:
text – str
Sets the subtitle text that should be rendered together with this video frame to text
.
See also
- PySide6.QtMultimedia.QVideoFrame.size()#
- Return type:
Returns the dimensions of a video frame.
- PySide6.QtMultimedia.QVideoFrame.startTime()#
- Return type:
int
Returns the presentation time (in microseconds) when the frame should be displayed.
An invalid time is represented as -1.
See also
- PySide6.QtMultimedia.QVideoFrame.subtitleText()#
- Return type:
str
Returns the subtitle text that should be rendered together with this video frame.
See also
- PySide6.QtMultimedia.QVideoFrame.surfaceFormat()#
- Return type:
Returns the surface format of this video frame.
- PySide6.QtMultimedia.QVideoFrame.swap(other)#
- Parameters:
other –
PySide6.QtMultimedia.QVideoFrame
Swaps the current video frame with other
.
- PySide6.QtMultimedia.QVideoFrame.toImage()#
- Return type:
Based on the pixel format converts current video frame to image.
- PySide6.QtMultimedia.QVideoFrame.unmap()#
Releases the memory mapped by the map()
function.
If the MapMode
included the WriteOnly
flag this will persist the current content of the mapped memory to the video frame.
unmap() should not be called if map()
function failed.
See also
- PySide6.QtMultimedia.QVideoFrame.width()#
- Return type:
int
Returns the width of a video frame.