1520332 - Screensaver not disabled on Hangouts call

Status: RESOLVED DUPLICATE of bug 1434601

(Core :: WebRTC: Audio/Video, defect)

Description

[Chris Pearce [:cpearce (Not reading bugmail)]]

I just had a hangouts call with an interview candidate, and the screensaver kicked in multiple times. Windows 10 x64, Nightly 2019-01-14.

Comment 1

[Paul Adenot (:padenot)]

Nils, do you know if we've changed something recently about this?

Comment 2

[Dan Minor [:dminor]]

:jib, from the standup it sounded like you had some insight into this problem?

Comment 3

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

Yes, Chris showed me this code, which suggests both audio and video need to be present on a video element for the wakelock to take [1]:

bool HTMLVideoElement::ShouldCreateVideoWakeLock() const {
  // Make sure we only request wake lock for video with audio track, because
  // video without audio track is often used as background image which seems no
  // need to hold a wakelock.
  return HasVideo() && HasAudio();
}

From experimenting with web console during a Hangouts call, I inspected the main video element (of the peer, not self view) to learn its class name ("Gv1mTb-aTv5jf" in my case), and found it does not appear to have audio:

  » document.getElementsByClassName("Gv1mTb-aTv5jf")[0].srcObject.getAudioTracks().length
    0

[1] https://searchfox.org/mozilla-central/rev/dac799c9f4e9f5f05c1071cba94f2522aa31f7eb/dom/html/HTMLVideoElement.cpp#286

Comment 4

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

The same problem happens with Google Meet. Their team is looking into it.