1506290 - Implement `document.autoplayPolicy` API

Status: RESOLVED FIXED

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

Description

[Alastor Wu [:alwu]]

`document.autoplayPolicy` returns a enum string that can change overtime based on user session activity [1]:

- “allowed” if autoplay is currently allowed.
- “allowed-muted” if muted video autoplay is currently allowed.
- “disallowed” is autoplay is not current allowed.
- “prompt” if autoplay will trigger a prompt

[1] https://github.com/WICG/autoplay/issues/1

Comment 1

[Alastor Wu [:alwu]]

Attachment: Bug 1506290 - part1 : implement 'document.autoplayPolicy'.

`document.autoplayPolicy` returns a enum string that can change overtime based on user session activity:

- “allowed” if autoplay is currently allowed.
- “allowed-muted” if muted video autoplay is currently allowed.
- “disallowed” is autoplay is not current allowed.
- “prompt” if autoplay will trigger a prompt

Comment 2

[Alastor Wu [:alwu]]

Before fixing bug1493766, we can't write tests because now AutoplayPolicy::IsAllowedToPlay() would return incorrectly result under some situaions. 

I will write the wpt-test after fixing bug1493766.

Comment 3

[Alastor Wu [:alwu]]

The proposal [1] defines that `document.autoplayPolicy` returns a single enum string, but it doesn't meet our current implementation. “allowed-muted” and “prompt” can exist at the same time. 

Therefore, we can't implement this API now, we need to wait for the decision about whether shipping the doorhanger. If not, we can implement this single enum version, but if we want to ship with doorhanger, we need to modify the proposal in order to make API return multiple enums strings.

Comment 4

[Alastor Wu [:alwu]]

Attachment: Bug 1506290 - part2 : add test.

Comment 5

[Alastor Wu [:alwu]]

Try result looks good. https://treeherder.mozilla.org/#/jobs?repo=try&revision=f9d16f3ac3f8c3cc4af228d3894a4c04606c18b9

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/63c3828351f0
part1 : implement 'document.autoplayPolicy'. r=baku,cpearce
https://hg.mozilla.org/integration/autoland/rev/3420cf8f79a9
part2 : add test. r=cpearce

Comment 7

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/63c3828351f0
https://hg.mozilla.org/mozilla-central/rev/3420cf8f79a9

Comment 8

[Eric Shepherd [:sheppy]]

:cmills-- when we get to the docs for this one, I'll take it.

Comment 9

[Chris Mills [:cmills]]

(In reply to Eric Shepherd [:sheppy] from comment #8)

:cmills-- when we get to the docs for this one, I'll take it.

WFM; I've added you to the relevant MDN roadmap card: https://trello.com/c/4emMB6Y8/146-autoplay-api-fx-66

Comment 10

[Chris Mills [:cmills]]

Again, I don't think this is available in 66; see https://bugzilla.mozilla.org/show_bug.cgi?id=1487844#c9. I could be wrong.

Comment 11

[Alastor Wu [:alwu]]

This API is controled by the pref "dom.media.autoplay.autoplay-policy-api", which is default off. If user turns on this pref in 66, then they can use the API no matter whether we enable blocking autoplay or not.

Comment 12

[Eric Shepherd [:sheppy]]

I've added this to the "experimental features in Firefox" page. It's currently mentioned on the Fx for 66 page, but can be removed if we decide to.

Comment 13

[Alastor Wu [:alwu]]

(In reply to Eric Shepherd [:sheppy] from comment #12)

I've added this to the "experimental features in Firefox" page. It's currently mentioned on the Fx for 66 page, but can be removed if we decide to.

It sounds good to me to mention that this API is just an experimental feature which hasn't be a part of the offical spec, thank you.

Comment 14

[Chris Mills [:cmills]]

The docs for this one sound done, for now.