Qt Creator + PySide2: QFormBuilder was unable to create a custom widget of the class 'QVideoWidget'

after porting app from pyqt5 to pyside2, everything is functioning properly except the qvideowidget. it's promoted on the qt creator form exactly the same as the way it was in pyqt5, but with the equivalent pyside2 header file. (see attachment)

error:
"QFormBuilder was unable to create a custom widget of the class 'QVideoWidget'; defaulting to base class 'QWidget'."

i can hear the video's audio playing, but the video won't display because the widget isn't able to promote to qvideowidget.

it seems to be an issue in qt creator, because creating and printing a QVideoWidget like so:

video_widget = QVideoWidget print(testVideoWidget)
print(video_widget) 

results in the following output:

13:53:44: Starting /usr/bin/python3 -u /home/username/apps/untitled/main.py...
<class 'PySide2.QtMultimediaWidgets.QVideoWidget'>

 which seems to suggest python / pyside are functioning properly