QVideoFrame

The QVideoFrame class represents a frame of video data. More

Inheritance diagram of PySide2.QtMultimedia.QVideoFrame

Synopsis

Functions

Static functions

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. 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 . A QVideoFrame may be constructed from any buffer type by subclassing the QAbstractVideoBuffer class.

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 PySide2.QtMultimedia.QVideoFrame

PySide2.QtMultimedia.QVideoFrame(buffer, size, format)

PySide2.QtMultimedia.QVideoFrame(image)

PySide2.QtMultimedia.QVideoFrame(other)

PySide2.QtMultimedia.QVideoFrame(bytes, size, bytesPerLine, format)

param bytes

int

param format

PixelFormat

param bytesPerLine

int

param image

PySide2.QtGui.QImage

param size

PySide2.QtCore.QSize

param buffer

PySide2.QtMultimedia.QAbstractVideoBuffer

param other

PySide2.QtMultimedia.QVideoFrame

Constructs a null video frame.

Constructs a video frame from a buffer with the given pixel format and size in pixels.

Note

This doesn’t increment the reference count of the video buffer.

Constructs a video frame of the given pixel format and size in pixels.

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.

PySide2.QtMultimedia.QVideoFrame.FieldType

Specifies the field an interlaced video frame belongs to.

Constant

Description

QVideoFrame.ProgressiveFrame

The frame is not interlaced.

QVideoFrame.TopField

The frame contains a top field.

QVideoFrame.BottomField

The frame contains a bottom field.

QVideoFrame.InterlacedFrame

The frame contains a merged top and bottom field.

PySide2.QtMultimedia.QVideoFrame.PixelFormat

Enumerates video data types.

Constant

Description

QVideoFrame.Format_Invalid

The frame is invalid.

QVideoFrame.Format_ARGB32

The frame is stored using a 32-bit ARGB format (0xAARRGGBB). This is equivalent to Format_ARGB32 .

QVideoFrame.Format_ARGB32_Premultiplied

The frame stored using a premultiplied 32-bit ARGB format (0xAARRGGBB). This is equivalent to Format_ARGB32_Premultiplied .

QVideoFrame.Format_RGB32

The frame stored using a 32-bit RGB format (0xffRRGGBB). This is equivalent to Format_RGB32

QVideoFrame.Format_RGB24

The frame is stored using a 24-bit RGB format (8-8-8). This is equivalent to Format_RGB888

QVideoFrame.Format_RGB565

The frame is stored using a 16-bit RGB format (5-6-5). This is equivalent to Format_RGB16 .

QVideoFrame.Format_RGB555

The frame is stored using a 16-bit RGB format (5-5-5). This is equivalent to Format_RGB555 .

QVideoFrame.Format_ARGB8565_Premultiplied

The frame is stored using a 24-bit premultiplied ARGB format (8-5-6-5).

QVideoFrame.Format_BGRA32

The frame is stored using a 32-bit BGRA format (0xBBGGRRAA).

QVideoFrame.Format_BGRA32_Premultiplied

The frame is stored using a premultiplied 32bit BGRA format.

QVideoFrame.Format_ABGR32

The frame is stored using a 32-bit ABGR format (0xAABBGGRR).

QVideoFrame.Format_BGR32

The frame is stored using a 32-bit BGR format (0xBBGGRRff).

QVideoFrame.Format_BGR24

The frame is stored using a 24-bit BGR format (0xBBGGRR).

QVideoFrame.Format_BGR565

The frame is stored using a 16-bit BGR format (5-6-5).

QVideoFrame.Format_BGR555

The frame is stored using a 16-bit BGR format (5-5-5).

QVideoFrame.Format_BGRA5658_Premultiplied

The frame is stored using a 24-bit premultiplied BGRA format (5-6-5-8).

QVideoFrame.Format_AYUV444

The frame is stored using a packed 32-bit AYUV format (0xAAYYUUVV).

QVideoFrame.Format_AYUV444_Premultiplied

The frame is stored using a packed premultiplied 32-bit AYUV format (0xAAYYUUVV).

QVideoFrame.Format_YUV444

The frame is stored using a 24-bit packed YUV format (8-8-8).

QVideoFrame.Format_YUV420P

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_YUV422P

The frame is stored using an 8-bit per component planar YUV format with the U and V planes horizontally sub-sampled, i.e. the width of the U and V planes are half that of the Y plane, and height of U and V planes is the same as Y.

QVideoFrame.Format_YV12

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

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

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

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

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

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 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

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 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

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 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

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 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

The frame is stored using an 8-bit greyscale format.

QVideoFrame.Format_Y16

The frame is stored using a 16-bit linear greyscale format. Little endian.

QVideoFrame.Format_Jpeg

The frame is stored in compressed Jpeg format.

QVideoFrame.Format_CameraRaw

The frame is stored using a device specific camera raw format.

QVideoFrame.Format_AdobeDng

The frame is stored using raw Adobe Digital Negative (DNG) format.

QVideoFrame.Format_User

Start value for user defined pixel formats.

PySide2.QtMultimedia.QVideoFrame.availableMetaData()
Return type

Returns any extra metadata associated with this frame.

PySide2.QtMultimedia.QVideoFrame.bits()
Return type

str

Returns a pointer to the start of the frame data buffer.

This value is only valid while the frame data is mapped .

If the buffer was not mapped with read access, the contents of this buffer will initially be uninitialized.

PySide2.QtMultimedia.QVideoFrame.buffer()
Return type

PySide2.QtMultimedia.QAbstractVideoBuffer

Returns underlying video buffer or null if there is none.

PySide2.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 .

PySide2.QtMultimedia.QVideoFrame.bytesPerLine()
Return type

int

Returns the number of bytes in a scan line.

Note

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 pixel format .

This value is only valid while the frame data is mapped .

PySide2.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

setEndTime()

PySide2.QtMultimedia.QVideoFrame.fieldType()
Return type

FieldType

Returns the field an interlaced video frame belongs to.

If the video is not interlaced this will return WholeFrame.

See also

setFieldType()

PySide2.QtMultimedia.QVideoFrame.handle()
Return type

object

Returns a type specific handle to a video frame’s buffer.

For an OpenGL texture this would be the texture ID.

See also

handle()

PySide2.QtMultimedia.QVideoFrame.handleType()
Return type

HandleType

Returns the type of a video frame’s handle.

PySide2.QtMultimedia.QVideoFrame.height()
Return type

int

Returns the height of a video frame.

PySide2.QtMultimedia.QVideoFrame.image()
Return type

PySide2.QtGui.QImage

Based on the pixel format converts current video frame to image.

static PySide2.QtMultimedia.QVideoFrame.imageFormatFromPixelFormat(format)
Parameters

formatPixelFormat

Return type

Format

Returns an image format equivalent to a video frame pixel format . If there is no equivalent format Format_Invalid is returned instead.

Note

In general QImage does not handle YUV formats.

PySide2.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

PySide2.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

PySide2.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.

PySide2.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

PySide2.QtMultimedia.QVideoFrame.map(mode)
Parameters

modeMapMode

Return type

bool

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 QAbstractVideoBuffer::ReadOnly flag the mapped memory will be populated with the content of the video frame when initially mapped. If the map mode includes the QAbstractVideoBuffer::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.

PySide2.QtMultimedia.QVideoFrame.mapMode()
Return type

MapMode

Returns the mode a video frame was mapped to system memory in.

See also

map() MapMode

PySide2.QtMultimedia.QVideoFrame.mappedBytes()
Return type

int

Returns the number of bytes occupied by the mapped frame data.

This value is only valid while the frame data is mapped .

See also

map()

PySide2.QtMultimedia.QVideoFrame.metaData(key)
Parameters

key – str

Return type

object

Returns any metadata for this frame for the given 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.

See also

setMetaData()

PySide2.QtMultimedia.QVideoFrame.__ne__(other)
Parameters

otherPySide2.QtMultimedia.QVideoFrame

Return type

bool

Returns true if this QVideoFrame and other do not reflect the same frame.

PySide2.QtMultimedia.QVideoFrame.__eq__(other)
Parameters

otherPySide2.QtMultimedia.QVideoFrame

Return type

bool

Returns true if this QVideoFrame and other reflect the same frame.

PySide2.QtMultimedia.QVideoFrame.pixelFormat()
Return type

PixelFormat

Returns the color format of a video frame.

static PySide2.QtMultimedia.QVideoFrame.pixelFormatFromImageFormat(format)
Parameters

formatFormat

Return type

PixelFormat

Returns a video pixel format equivalent to an image format . If there is no equivalent format QVideoFrame::InvalidType is returned instead.

Note

In general QImage does not handle YUV formats.

PySide2.QtMultimedia.QVideoFrame.planeCount()
Return type

int

Returns the number of planes in the video frame.

This value is only valid while the frame data is mapped .

See also

map()

PySide2.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

endTime()

PySide2.QtMultimedia.QVideoFrame.setFieldType(arg__1)
Parameters

arg__1FieldType

Sets the field an interlaced video frame belongs to.

See also

fieldType()

PySide2.QtMultimedia.QVideoFrame.setMetaData(key, value)
Parameters
  • key – str

  • value – object

Sets the metadata for the given key to value .

If 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.

See also

metaData()

PySide2.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

startTime()

PySide2.QtMultimedia.QVideoFrame.size()
Return type

PySide2.QtCore.QSize

Returns the dimensions of a video frame.

PySide2.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

setStartTime()

PySide2.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.

should not be called if map() function failed.

See also

map()

PySide2.QtMultimedia.QVideoFrame.width()
Return type

int

Returns the width of a video frame.