Firefox has long had problems with rendering images on the move. Compared to other browsers, the image is jerky and slightly blurry in motion.
This is especially noticeable when running subtitles, watching hockey, or any scene where there is more sustained motion.
The problem is probably at a level somewhere around HW-acceleration and vertical sync.
I want to report this to the developers and ask for improvements - the video is not easy to watch via FF.
I'm posting a link to a test video in Full HD, using the 15:17-15:31 minute segment. For example in Edge or Chrome it runs fine - on FF the movement is noticeably choppy and jerky.
If I'm out of line here, please advise me how to inform the developers about this. I don't want to lose Firefox - it's my favourite browser, but this way I have to use 2 unnecessarily.