QMediaPlayer doesn't play any audio/video under Mac OS X (High Sierra)

Hello!

I'm new to Python and Qt5. I'm trying to test and learn how QMediaPlayer works with tutorials on the Internet, but I can't get it to play any video/audio with the code examples like this:

https://pythonprogramminglanguage.com/pyqt5-video-widget/

It doesn't give out any errors. Just hanging when trying to play a video or an audio file. Its state is "playing", but nothing is actually being played. I can just toggle between play/pause states of the button without any changes. Do you have any ideas, what can I do with this? Is it compatible with macOS High Sierra? Maybe, I need some specific adjustments for this os? Thank you in advance!