1762617 - https://reference.dashif.org/dash.js/nightly/samples/dash-if-reference-player/index.html has a/v sync issues

Status: NEW

(Core :: Audio/Video: Playback, defect, P3)

Description

[Jeff Muizelaar [:jrmuizel]]

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

Comment 1

[Jeff Muizelaar [:jrmuizel]]

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

Comment 2

[Alastor Wu [:alwu]]

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

Comment 3

[Jeff Muizelaar [:jrmuizel]]

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

Comment 4

[Jeff Muizelaar [:jrmuizel]]

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

Comment 5

[Jeff Muizelaar [:jrmuizel]]

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

Comment 6

[Jim Mathies [:jimm]]

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

Comment 7

[Paul Adenot (:padenot)]

(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.

Comment 8

[Jeff Muizelaar [:jrmuizel]]

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

Comment 9

[Paul Adenot (:padenot)]

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

Comment 10

[Jim Mathies [:jimm]]

I'm not having any luck reproducing this.