I just write a simple applications for Windows using PySide2 and Python 3.8 that is a reduced web browser (it can not navigate everywhere but only in some specific web pages) and it has to open html pages embedding audio or video files or just pointing to audio and video files. Everything works apart for the major part of video files it has to support. In practice, instead of playing mkv, avi, mov and wmv files the only thing I can do with them is download them. It plays well only webm video files and seems that it could play also mp4 video files because it opens them but it does not start them to play. Seems as it has no permission to do that (not by my side) or that some video codecs is missing. I just tryed to move to PySide6 but at the moment I am not able to fix other problems not present on PySide2. Did anyone had similar problems? Thanks, Massimo