Ever since you guys moved to the new video player, the videos will randomly just stop playing for me and act like the video was complete. So even when I reload the page and hit play, it won't resume from where it left off and I have to manually move the slider. Sometimes it won't happen at all in a 2 hr video, and sometimes it will happen every 15 minutes. It doesn't feel consistent. It happens in both Firefox 51.0.1 and Chrome Canary 58.0.2999.0 (and the last several versions since they update it pretty frequently). My OS is Windows 10. My IP address is 184.108.40.206.
I'm having this exact issue except I can only make it 10-15 seconds in a video at a time usually. The video player also seems to skip a second every 5 seconds or so. I'm having to download all the videos to watch them currently. This happens in both HTML 5 and Progressive at all qualities. Youtube works fine.