Discovered from https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/discuss-webrtc/Gqo2MfnQWkw/sOZlb2EqDgAJ

There is a pernosco recording at https://pernos.co/debug/dxLVskE-28Jb11gvrw4iSA/index.html

The black frame reaches MediaPipeline but is dropped at https://searchfox.org/mozilla-central/rev/b38e3beb658b80e1ed03e0fdf64d225bd4a40327/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp#1128.

We might want to propagate the active state into the VideoFrameConverter.

There's a second bug here where frames from SameFrameTimer don't get sent due to bug 1522238. Frames broadcast by the timer have the same timestamp as the last frame and get dropped upstream.

This didn't seem to impact my manual test of the original STR, but it impacts the mochitest I wrote.

Depends on D40597

Depends on D40598

https://hg.mozilla.org/mozilla-central/rev/d2a030d452cb
https://hg.mozilla.org/mozilla-central/rev/91d822ac2647
https://hg.mozilla.org/mozilla-central/rev/acd8b80087e0

Comment on attachment 9082952 [details]
Bug 1570673 - Add an active state to VideoFrameConverter and propagate it from MediaPipeline. r?bwc

Beta/Release Uplift Approval Request

• User impact if declined: Chrome and safari (possibly also Edge) will not be able to receive audio from Firefox in video calls in some cases
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: Join a room on https://appr.tc with Firefox
  Mute the camera in Firefox
  Join the same room (same URL) with Chrome or Safari
  Mute the microphone in Chrome or Safari
  Expected: you can hear yourself
  With bug: you can only hear yourself after unmuting the camera in Firefox
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Well covered with unittests and mochitests
• String changes made/needed:

ESR Uplift Approval Request

• If this is not a sec:{high,crit} bug, please state case for ESR consideration: 68 regression that got public attention: https://groups.google.com/d/msg/discuss-webrtc/Gqo2MfnQWkw/XZYGhjHvDQAJ
• User impact if declined: Chrome and safari (possibly also Edge) will not be able to receive audio from Firefox in video calls in some cases
• Fix Landed on Version: 70
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Well covered with unittests and mochitests
• String or UUID changes made by this patch:

Verified fixed on the latest Firefox Nightly (20190808214929) on Windows 10 and Mac OS 10.14.6

Comment on attachment 9082951 [details]
Bug 1570673 - Add mochitest. r?bwc

Fixes a WebRTC interop bug which can cause users of other browsers to not receive audio from Firefox users. Approved for 69.0b13 and 68.1esr.

https://hg.mozilla.org/releases/mozilla-beta/rev/0291822afd2d
https://hg.mozilla.org/releases/mozilla-beta/rev/c63aa7985beb
https://hg.mozilla.org/releases/mozilla-beta/rev/1b6a325b60ba

At least the second patch needs rebasing for ESR68.

Verified fixed on Windows 10, Mac OS 10.14.6 and Ubuntu 18.04 using Firefox Beta 69.0b13 (20190812173625)

Slight collision with bug 1556696. I'll have the 2nd patch up rebased for esr68 in a bit.

Rebased attachment 9082952 [details] on top of esr68. Carries forward the r+.

https://hg.mozilla.org/releases/mozilla-esr68/rev/4a013bedd9b2
https://hg.mozilla.org/releases/mozilla-esr68/rev/634e8c6ee728
https://hg.mozilla.org/releases/mozilla-esr68/rev/23ede143e5f2

Verified fixed on Windows 10, Mac OS 10.14.6 and Ubuntu 18.04 using Firefox 68.1.0 ESR (20190814031227) downloaded from https://treeherder.mozilla.org/#/jobs?repo=mozilla-esr68