1736210 - amp reddit block automatic (audio) playback not working

Status: RESOLVED WORKSFORME

(Core :: Audio/Video, defect, P3)

Description

[Djfe]

Attachment: Screenshot_20211017-115627~2.jpg

User Agent: Mozilla/5.0 (Android 10; Mobile; rv:93.0) Gecko/93.0 Firefox/93.0

Steps to reproduce:

I opened
https://amp.reddit.com/r/dubstep/comments/24zb4o/james_blake_limit_to_your_love_turn_up_your_sub/
in Firefox on Android (Fenix)

Actual results:

It started the playback of the video in the second post of the page with audio turned on.
Audio should be blocked on autoplay (settings-wise)

I scroll down:
further videos from the next posts start playing video and audio. several videos/audios at the same time.

If I pause through the notification bar now, then all of them are paused at once.
If I scroll down further again afterwards, then the newly loaded posts have video with audio again.
From now on the Media control in the notification bar is broken. I can't pause playback through the notification bar anymore (attached screenshot)
Firefox starts lagging (the browser) and the video stutters due to buffering/slow decoding.
I need to close the tab to be able to use my device again else all the audio keeps playing in the background even in other apps.

Affected are Release and Nightly of Fenix

Expected results:

Audio should have been blocked on all of these autoplayback videos according to the setting.

Comment 1

[Bryce Seager van Dyk [:bryce] (he/him) - Not reading bugmail]

Are you interacting with the page and then it's autoplaying the media? Firefox uses 'gesture activation' to determine if autoplay is allowed -- if a page has been interacted with in various ways, autoplay will be allowed. There's a wiki page that goes into this in more detail that may be of interest.

Comment 2

[Alastor Wu [:alwu]]

I can reproduce this issue on my pixel5 as well. After clicking the button to select continue viewing this page on the browser, the click would activate the page which would allow all autoplay media to start. I also tried this issue on Chrome, but they can block those iframes well even if they also uses sticky activation to block media.

So I check their blog and found that they would restrict the delegate the autoplay permission to CORS iframe, if the iframe doesn't have keyword allow=autoplay. We also had a similar policy at the time before, but that was all removed in bug1470346 in order to simply the behavior.

Maybe we should consider to add that constraint back again, not to activate all iframes at once.

Comment 3

[Alastor Wu [:alwu]]

In addition, you can workaround this problem by setting media.autoplay.blocking_policy to 1 or 2, which uses different blocking policy.

Comment 4

[Djfe]

:bryce
it's exactly like :alwu explained
Videos start playing after clicking the button

I open a new tab, press paste link from clipboard and then wait till the page is loaded.
If I press "Continue" (the option with the chrome icon), then it is ready to start playing videos.
I still need to scroll down a bit or close the keyboard though, to make the videos close enough to the viewport otherwise they won't start playing.

Desktop doesn't seem to be affected (fully)
All videos start playing at the same time but atleast with no audio.

On mobile playing the fact that all videos are playing at the same time makes Firefox laggish, on desktop I have no such problem since my cpu/gpu have enough power to decode and render everything.

Comment 6

[Djfe]

this was either fixed or reddit was changed in the past year