Bug 172762 – YouTube video screen freezes after 3 seconds when mouse does not move

• Status: NEW
• Component: Media

[Roland Soos]

When I'm viewing any YouTube video in Safari the screen freezes after the mouse not moved for 3 seconds. The sound of the video in the background continue to play, just the video freezed. When I'm moving the mouse all the time the video plays just fine, but it isn't normal.

Here is a video demonstration of the issue: https://www.youtube.com/edit?o=U&video_id=3U5eW-4Orrk

This issue is haunting me for ages. I have a Macbook Air 2014 early and the problem started to happen 2 years ago. Now I have a brand new Macbook Air 2015 early and the same issue happens. It isn't happen all the time, but when it starts to freeze, you can not make it stop. Restart solves it and sometimes the sleep.

MacOs 10.12.6
Safari: 10.1.2 (12603.3.1) 

I do not have any browser extension installed into Safari. Also Chrome doesn't produce the same issue.

[Roland Soos]

Also I can confirm that Vimeo, YouTube iframe api suffers from this problem too. 

Dailymotion and Twitch seem OK.

[Roland Soos]

Facebook videos also freeze in fullscreen.

[Roland Soos]

Logs during playback freeze: https://pastebin.com/WHCCzKNS

[Radar WebKit Bug Importer]

<rdar://problem/32554821>

[Roland Soos]

Update: It might be related that we have two account in OSX and both user switch to their own account when they use the Macbook Air.

My last test:
Youtube were open in both account.
I played a Youtube video on account1 and it freezed as on my previous video.
Then I switched over account2 and the YouTube does not freeze.
In account2 I closed Safari and started again and started to play a video. It freezed like on my previous video.
Then switched back to account1 and the video does not freeze...


Also we might sleep it while YouTube video is playing in account1 and we might log into account2 after sleep. It might be related also.

[Roland Soos]

(In reply to Roland Soos from comment #5)
> Update: It might be related that we have two account in OSX and both user
> switch to their own account when they use the Macbook Air.
> 
> My last test:
> Youtube were open in both account.
> I played a Youtube video on account1 and it freezed as on my previous video.
> Then I switched over account2 and the YouTube does not freeze.
> In account2 I closed Safari and started again and started to play a video.
> It freezed like on my previous video.
> Then switched back to account1 and the video does not freeze...
> 
> 
> Also we might sleep it while YouTube video is playing in account1 and we
> might log into account2 after sleep. It might be related also.

Current OSX version is: 10.12.6 beta (16G23a)

[Roland Soos]

This issue still exists in High Sierra 10.13 (17A365) and Safari Version 11.0 (13604.1.38.1.6)

I'm pretty sure that the problem can be reproduced if you have at least 2 users in OSX and you use both account for browsing and playing HTML5 videos and one of the user will have this freezing issue. Do not sing out with users, just use the user switching.

[Roland Soos]

With MacOs 10.14.1 and Safari 12.0.1 this issue got a little bit better. Instead of the past effect, the video started to lag in fullscreen: https://www.youtube.com/watch?v=BgnsH2DPBfI

[Roland Soos]

Another strange artifact: https://www.youtube.com/watch?v=bPsV9UsN37I

In fullscreen when the mouse is not moving around, the video starts to jump back to old frames.