Firefox out of sync

[NeonGOD 3]

I got my computer stolen a couple of month ago and i just got a new one the other day..  so i installed emby again but when i run it in the web app it lags all the time..  i first thought it might had to do with windows 10 redstone update..  or maybe some compability issues with my new hardware but nooo..  it's firefox..  i use to run webapp in firefox without any problems but now sound is out of sync..   but it doesn't happen in chrome??  chrome functions great..  but i hate using chrome i rather stay with firefox...  any ideas what might be causing this ?

[NeonGOD 3]

Okay..  plot thickens..   when i run it from the same machine it's out of sync.. and i can't get any subs..  but from another machine it works flawlessly..  i tried to run it from 32 bit and 64 bit browser.. same..  tried to reinstall browser and no addons.. same

[Luke 42083]

Try lowering the in-app bitrate to force full video transcoding and that will fix it. When stream copying without re-encoding it's currently a known issue with firefox.