Now first of all, I know that AirPlay 1 has about 2 seconds of delay, and this is not the delay I'm talking about here. Usually when you stream from a Mac or iOS device to an AirPlay receiver, the OS will account for these two seconds and delay the video playback accordingly so that they are in perfect sync (at least with video streams where this is possible, like QuickTime files, videos in Safari, etc.). My issue is that whenever I play a video in Safari like a YouTube or Netflix video, or a video file in QuickTime, or anything like that from my iMac while streaming to the HomePod, video and audio won't be in sync, the video will buffer to account for the AirPlay lag but then it will still be about 0.5 seconds ahead of the audio. I've restarted both devices several times, dis- and reconnected my Mac with the network multiple times, nothing would work. The peculiar thing is that this only happens on this very iMac to me; when I watch videos on my iPad or iPhone and even my MacBook while AirPlay'ing to my HomePod, video and audio will be in perfect sync. I even created another user account on my iMac to try it out from, and on that one, video and audio also were perfectly synced up, which leads me to believe that there's something "wrong" with that particular user account on my iMac. Maybe a corrupted preferences file or something that's interfering/delaying the AirPlay stream for more than the usual 2 seconds? Does anyone have an idea of what else I could try? Are there any hidden AirPlay preferences or so that one could tweak, any pref or plist files that one could try to delete, or any way to see if something's interfering with the network or AirPlay stream? I suppose I could "fix" this by moving over entirely to the new user account, but moving everything over and setting everything up again seems like a tremendous amount of work for such a relatively "minor" (but nevertheless extremely annoying) bug.