Falkon and other QtWebEngine clients can't play video. Any video on youtube or
peertube (e.g. at https://kde.org/announcements/plasma-5.18.0.php ) or HTML5
video test pages.

Buffer is filling and network shows video file is loaded but it doesn't start
to actually play. YouTube shows previews on timeline, but not the first frame.
Video without poster has no shown content.

I've noticed this after update to Qt 5.14.1, though maybe this was present
earlier with 5.14, I'm not sure.

Noticed at least with snapshot 20200201 and present till current 20200213.

Can't see anything related in logs of Falkon or when run QtWebEngine from my
app in Qt Creator.