1705643 - With native fullscreen enabled there is no smooth transition when switching via video controls

Status: NEW

(Core :: Widget: Cocoa, defect, P3)

Description

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:89.0) Gecko/20100101 Firefox/89.0 ID:20210415214643

The problem as reported can be seen when watching videos on different websites. Hereby the transition in and out of fullscreen isn't smooth anymore but interrupted for some milliseconds by the page content bleeding through. As such when going into full-screen the video isn't immediately displayed. Note that this is a regression in Firefox 89 and cannot be seen in the latest Firefox 88 DevEdition build.

Steps to reproduce:

1. Load any page that contains a video like https://www.youtube.com/watch?v=uarBtleZ3Ck
2. Start playing the video
3. Click the full-screen icon from the video controls

With step 3 there is a noticeable delay until the video is shown in full-screen and the page's content is displayed.

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Actually it seems to be related to my profile and not the version of Firefox. When I use the Nightly profile with the above mentioned DevEdition build the same behavior can be seen. Running with all extensions and themes disabled doesn't make a difference.

Comment 2

[Timothy Nikkel (:tnikkel)]

There has been work on the full screen transition on mac lately. I think widget cocoa is the best place to get eyes on this for people familiar with that work.

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+1]]

This is actually a problem with the native full-screen API that can be enabled with the preference full-screen-api.macos-native-full-screen. Here the updated steps:

1. Load any page that contains a video like https://www.youtube.com/watch?v=uarBtleZ3Ck
2. Start playing the video
3. Click the full-screen icon from the video controls and exit full screen afterward (all smooth)
4. Set full-screen-api.macos-native-full-screen=true
5. Repeat 3) (sluggish transition)

Comment 4

[Martin Balfanz [:mbalfanz]]

Unlikely that this is a regression as it's using a work-in-progress feature behind a pref. It seems similar to bug 1696428.

Comment 5

[Henrik Skupin [:whimboo][⌚️UTC+1]]

(In reply to Martin Balfanz [:mbalfanz] from comment #4)

Unlikely that this is a regression as it's using a work-in-progress feature behind a pref.

Yes, for got to remove the keywords after finding out that it is a pref'ed off feature.