1600063 - Recently, equalizer extensions cause html5 audio to lag when playing/pausing

Status: VERIFIED FIXED

(Core :: Audio/Video: Playback, defect, P2)

Description

[Shane Hughes [:aminomancer]]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:72.0) Gecko/20100101 Firefox/72.0

Steps to reproduce:

• Install an equalizer extension like "Audio Equalizer" or "H5EQ" on Firefox Nightly (only tested on Windows 10)
• Go to youtube or netflix or some other video website
• Press play, then press pause.
• Disable the extension, reload the video webpage, then do the same thing.

Actual results:

Upon clicking pause, the video takes longer than expected to pause, and the audio keeps going for like 3 seconds. For every html video player I've tested so far. I actually thought this was an issue with decoding until I realized the problem resolves when I disable my EQ. When you start the video back up again, they fall back in sync but that seems to be caused by the video skipping forward to catch up with the audio. Makes it pretty noticeable since you miss a couple seconds of video due to that.

Expected results:

The video and audio should both stop immediately when pausing and start immediately when playing. Up until this month, they did. These extensions worked fine for me and didn't have any noticeable side effects besides adding inline scripts to every page. So I don't think this is an unavoidable consequence of using an equalizer extension.

Comment 1

[Andreas Pehrson [:pehrsons]]

Thanks for filing!

This sounds like fallout from bug 1172394. I'm setting flags based on that assumption, but I'll need to look deeper into it.

Comment 2

[Andreas Pehrson [:pehrsons]]

I can confirm with https://addons.mozilla.org/en-US/firefox/addon/audio-equalizer-wext.

Comment 3

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1600063 - Clear future data when the DecodedStream mediasink stops playing. r?padenot

Comment 4

[Andreas Pehrson [:pehrsons]]

[Tracking Requested - why for this release]: Regression for popular audio addons. A webaudio node is also affected.

Comment 5

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1600063 - Add some logging for DecodedStream. r?padenot

Depends on D55981

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b7ef124e4519
Clear future data when the DecodedStream mediasink stops playing. r=padenot
https://hg.mozilla.org/integration/autoland/rev/0ccc77928faa
Add some logging for DecodedStream. r=padenot

Comment 7

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/b7ef124e4519
https://hg.mozilla.org/mozilla-central/rev/0ccc77928faa

Comment 8

[Andreas Pehrson [:pehrsons]]

Comment on attachment 9113802 [details]
Bug 1600063 - Clear future data when the DecodedStream mediasink stops playing. r?padenot

Beta/Release Uplift Approval Request

• User impact if declined: Audio equalizer addons result in a/v sync issues, and pausing/seeking where audio takes some time to stop across all sites. Some sites are natively affected, soundcloud is likely one such high profile site.
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: See comment 0. Use https://addons.mozilla.org/en-US/firefox/addon/audio-equalizer-wext/ for the first step.
• List of other uplifts needed: None
• Risk to taking this patch: Medium
• Why is the change risky/not risky? (and alternatives if risky): Considering what we do in the patch I'd consider it low risk, but fallout from this code can sometimes be unexpected and hard to overview, so I err on the safe side and say medium.
  The patch adds code that does things to 1) DecodedStream, on the owner thread (single thread - no race issues), 2) SourceMediaTrack, behind its Mutex (locked mutex - no race issues).
• String changes made/needed:

Comment 9

[Julien Cristau [:jcristau]]

Comment on attachment 9113802 [details]
Bug 1600063 - Clear future data when the DecodedStream mediasink stops playing. r?padenot

let's get this in 72.0b6 and be on the lookout for fallout

Comment 10

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/releases/mozilla-beta/rev/f74e1b9672b7
https://hg.mozilla.org/releases/mozilla-beta/rev/5f8350721877

Comment 11

[Alexandru Trif, Desktop QA [:atrif]]

Hello! Reproduced the issue using Firefox 72.0a1 (20191128214853) on Windows 10x64.
Te issue is verified fixed with Firefox 73.0a1 (20191216095052) on Windows 10x64, macOS 10.15 and Ubuntu 18.04. No lag is presented when using play/pause options with the addon from comment 8.
Unfortunately, the issue is still reproducing on Firefox 72.0b7 (20191213132525). The lag is still present after pausing the video on youtube or Netflix.
Andreas Pehrson can you please have a look? Thanks!

Comment 12

[Andreas Pehrson [:pehrsons]]

Ah, yes, that makes sense. We need bug 1597935 uplifted as well.

Comment 13

[Andreas Pehrson [:pehrsons]]

Per bug 1597935 comment 10 -- used the STR from this bug.