1477477 - Add pref to disable autoplaying of muted/silent media

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, enhancement)

Description

[Tom S [:evilpie]]

Attachment: Add pref to block muted autoplay media

Some people want the old behavior, I think this might be enough to justify this pref. It does cause the permission prompt message to be wrong: "... media with sound"

Comment 1

[Tom S [:evilpie]]

Oh btw, kind of weird how some media.autoplay prefs are in all.js and some in firefox.js.

Comment 2

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

Comment on attachment 8993901 [details] [diff] [review]
Add pref to block muted autoplay media

Review of attachment 8993901 [details] [diff] [review]:
-----------------------------------------------------------------

If you want the old behaviour, you may also want to search for "autoplay" in about:preferences and change the combobox from "ask" to "block", so that you're not prompted.

Please address the review comments before landing.

Note Chrome shipped with inaudible autoplay blocked on mobile by default, and the result was video ads switched to rendering to Canvas via video decoders implemented in JavaScript. Which caused severe battery drain on mobile. Which is why they stopped trying to block inaudible video, and why we don't either.

::: dom/media/AutoplayPolicy.cpp
@@ +116,4 @@
>  
>    // Muted content
>    if (aElement.Volume() == 0.0 || aElement.Muted()) {
> +    if (Preferences::GetBool("media.autoplay.muted", true)) {

Can you please make that:
if ((aElement.Volume() == 0.0 || aElement.Muted()) &&
    Preferences::GetBool("media.autoplay.allow-muted", true)) {
 //...

::: modules/libpref/init/all.js
@@ +570,5 @@
>  // By default, don't block WebAudio from playing automatically.
>  pref("media.autoplay.block-webaudio", false);
>  
> +// By default, don't block muted media from playing automatically.
> +pref("media.autoplay.muted", true);

Can you name this "media.autoplay.allow-muted", default true. Thanks.

Comment 3

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

(In reply to Tom Schuster [:evilpie] from comment #1)
> Oh btw, kind of weird how some media.autoplay prefs are in all.js and some
> in firefox.js.

The prefs that apply to both desktop & Fennec are in all.js.

The prefs that apply to desktop Firefox are in firefox.js.

The prefs that apply to Fennec are in mobile.js.

Comment 4

[Tom S [:evilpie]]

Awesome, thanks for the quick review.

> Note Chrome shipped with inaudible autoplay blocked on mobile by default,
> and the result was video ads switched to rendering to Canvas via video
> decoders implemented in JavaScript. Which caused severe battery drain on
> mobile. Which is why they stopped trying to block inaudible video, and why
> we don't either.

Interesting, I assumed we wanted to prevent people from being incentivized to use GIFs instead of videos.

media.autoplay.enabled.user-gestures-needed seems to be in all pref.js files.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/e384aedb30b6
Add preference for autoplaying muted media. r=cpearce

Comment 6

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/e384aedb30b6