Intent to ship: block audible autoplay media intervention
SUMMARY:
We intend to change the behaviour of HTMLMediaElement to block autoplay of
audible audio and video in Firefox on desktop and mobile.
We are not going to block WebAudio at the same time. While we do plan to block
audible autoplay of WebAudio content in the near future, we have not finalized
our WebAudio blocking logic or intended ship date for blocking WebAudio.
TIMELINE:
We intend to run shield studies on the user impact of enabling HTMLMediaElement
autoplay blocking. If those go well we hope to ship in Firefox 63 (2018-10-23)
or Firefox 64 (2018-12-11). Upon conclusion of our experiments, I’ll follow up
here with a confirmed ship date for this feature.
We hope to block autoplay in WebAudio in a release soon after, hopefully
Firefox 64 or 65.
DETAILS:
We intend to block autoplay of HTMLMediaElement in tabs which haven't had user
interaction. Web authors should assume that they require a user gesture (mouse
click on a "play" button for example) in order to play audible media.
HTMLMediaElements with a "muted" attribute or "volume=0" are still allowed to
play.
As with other browsers implementing this feature, we express playback being
blocked by rejecting the promise returned by HTMLMediaElement.play(). Web
authors should always check whether the promise returned by
HTMLMediaElement.play() is rejected, and handle that case accordingly.
We also plan to allow users to create their own whitelist of sites which they
trust to autoplay.
We are planning to experiment via shield studies with prompting users to
approve/block playback on sites that try to autoplay before receiving user
interaction.
ADVICE FOR WEB AUTHORS:
In general, the advice that applies to other browsers [1][2] with respect to
autoplaying media will apply to Firefox as well; you cannot assume that you can
just call HTMLMediaElement.play() for audible media and expect it to always
play. You should always check whether the play promise is rejected, and handle
that case accordingly.
For example:
var promise = document.querySelector('video').play();
if (promise !== undefined) {
promise.catch(error => {
// Auto-play was prevented
// Show a UI element to let the user manually start playback
}).then(() => {
// Auto-play started
});
}
(This example comes from WebKit’s announcement on blocking autoplay [2])
To test block autoplay in Firefox 63 (currently in Firefox Nightly channel),
download the latest Nightly and open about:config in the URL bar and set the
preferences:
media.autoplay.enabled=false
media.autoplay.enabled.user-gestures-needed=true
media.autoplay.ask-permission=true
Tracking bug: (block-autoplay)
https://bugzilla.mozilla.org/show_bug.cgi?id=1376321
If you find bugs, please file them via this link and CC or need-info me
(cpearce), and mark them blocking bug 1376321:
https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&component=Audio%2FVideo%3A%20Playback
I will follow up with a confirmed ship date for block audible autoplay in
Firefox once we have one.
[1] https://developers.google.com/web/updates/2017/09/autoplay-policy-changes
[2] https://webkit.org/blog/7734/auto-play-policy-changes-for-macos/
_______________________________________________
dev-platform mailing list
dev-platform@lists.mozilla.org
https://lists.mozilla.org/listinfo/dev-platform
