"""
Video frame pipeline
====================
:mod:`cv2PySide6.videostream` provides pipeline objects to get video stream in
numpy array.
"""
import numpy as np
from PySide6.QtCore import QObject, Signal, Slot
from PySide6.QtGui import QImage
from PySide6.QtMultimedia import (
QVideoFrame,
QMediaPlayer,
QVideoSink,
QMediaCaptureSession,
)
from qimage2ndarray import rgb_view # type: ignore[import]
from typing import Callable
__all__ = [
"FrameToArrayConverter",
"NDArrayVideoPlayer",
"NDArrayMediaCaptureSession",
]
[docs]class FrameToArrayConverter(QObject):
"""
Video pipeline component which converts ``QVideoFrame`` to numpy array and
emits to :attr:`arrayChanged`.
``QVideoFrame`` is first transformed to ``QImage`` and then converted to
array by :meth:`converter`.
``QVideoPlayer`` sends empty video frame at the end of video.
:meth:`ignoreNullFrame` determines whether null frame should be ignored or
empty array should be emitted.
"""
arrayChanged = Signal(np.ndarray)
def __init__(self, parent=None):
super().__init__(parent)
self._ignoreNullFrame = True
self._converter = rgb_view
[docs] def ignoreNullFrame(self) -> bool:
"""
If True, null ``QVideoFrame`` passed to :meth:`setVideoFrame` is be
ignored. Else, empty array with shape ``(0, 0, 0)`` is emitted.
"""
return self._ignoreNullFrame
@Slot(bool)
def setIgnoreNullFrame(self, ignore: bool):
"""Update :meth:`ignoreNullFrame`."""
self._ignoreNullFrame = ignore
@Slot(QVideoFrame)
def setVideoFrame(self, frame: QVideoFrame):
"""
Convert ``QVideoFrame`` to :class:`numpy.ndarray` and emit to
:meth:`setArray`.
"""
qimg = frame.toImage()
if qimg.isNull() and self.ignoreNullFrame():
pass
else:
array = self.convertQImageToArray(qimg)
self.arrayChanged.emit(array)
[docs] def converter(self) -> Callable[[QImage], np.ndarray]:
"""
Callable object to convert ``QImage`` instance to numpy array. Default is
``qimage2ndarray.rgb_view``.
"""
return self._converter
def setConverter(self, func: Callable[[QImage], np.ndarray]):
self._converter = func
[docs] def convertQImageToArray(self, qimg: QImage) -> np.ndarray:
"""
Convert *qimg* to numpy array. Null image is converted to empty array.
"""
if not qimg.isNull():
array = self.converter()(qimg).copy() # copy to detach reference
else:
array = np.empty((0, 0, 0))
return array
[docs]class NDArrayVideoPlayer(QMediaPlayer):
"""
Minimal implementation of video player which emits frames as numpy arrays to
:attr:`arrayChanged` signal.
User may use this class for convenience, or define their own pipeline.
"""
arrayChanged = Signal(np.ndarray)
def __init__(self, parent=None):
super().__init__(parent)
self._frame2Arr = FrameToArrayConverter(self)
self.setVideoSink(QVideoSink(self))
self.videoSink().videoFrameChanged.connect(
self.frameToArrayConverter().setVideoFrame
)
self.frameToArrayConverter().arrayChanged.connect(self.arrayChanged)
def frameToArrayConverter(self) -> FrameToArrayConverter:
return self._frame2Arr