If I run the "Akamai Low Latency Stream [Single rate]" it seems the A/V gradually comes out of sync.

This is on 2019 MBP with builtin audio

Safari and Chrome don't seem to have this problem.

I can also see that on my Windows 10 and 2021 MacBook Pro M1.

It looks like this probably caused by the dash.js using playbackRate to try to catch up the live video

See Native video element event: ratechange: 1.0399148845555657 style logs in the developer console

Firefox has ratechanges that happen continual during playback. This doesn't happen in Chrome.

Paul, any chance you have some cycles to poke at this for a cause?

(In reply to Jeff Muizelaar [:jrmuizel] from comment #5)

Firefox has ratechanges that happen continual during playback. This doesn't happen in Chrome.

Chrome and Firefox both show things like this in the console:

[94351][PlaybackController] Native video element event: ratechange: 1.00749943755062

so I'm not sure if you mean something else, or if this doesn't happen for you. A/V sync isn't amazing in Chrome nor in Firefox.

How long do I need it to play to see bad a/v sync? It's been playing for about 10min on a macbook and it's ok here.

30 seconds is enough for it be really bad for me.

I can't repro on my Linux box either. Maybe this is network-quality dependant? I'm on very reliable wifi and wired. Dunno.

I'm not having any luck reproducing this.