Intent to Experiment: Pause media playback on not-rendered iframes

[Chromestatus]

Contact emails

gabrie...@microsoft.com, ste...@microsoft.com

Explainer

https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/IframeMediaPause/iframe_media_pausing.md

Specification

None

Summary

Adds a "media-playback-while-not-rendered" permission policy to allow embedder websites to pause media playback of embedded iframes which aren't rendered - i.e. have their "display" property set to "none". This should allow developers to build more user-friendly experiences and to also improve the performance by letting the browser handle the playback of content that is not visible to users.

Blink component

Blink>Media

TAG review

None

TAG review status

Pending

Origin Trial documentation link

https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/IframeMediaPause/iframe_media_pausing.md

Risks

Interoperability and Compatibility

This feature is still being discussed with other browser vendors and the shape and functionality might not be final.

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/1082)

WebKit: No signal (https://github.com/WebKit/standards-positions/issues/409)

Web developers: Positive (https://github.com/whatwg/html/issues/10208) The web community seems to be interested in this feature, even though we may need to iterate on the user-facing API.

Other signals:

Ergonomics

This feature will be used with other audio rendering API's, like HTMLMediaElement and Web Audio. This new behavior should only take effect if web pages explicitly opt-in by overriding the permission policy's default state. Moreover, once the permission policy is used, it should help Chromium to be more optimized by pausing audio rendering for content that is not visible for the user.

Activation

Developers need to opt-in by setting "allow" property of an iframe. For example: <iframe src="https://foo.media.com" allow="media-playback-while-not-visible 'none'"></iframe>

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

None

Goals for experimentation

Ongoing technical constraints

None

Debuggability

None

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests?

Yes

We have implemented Blink webtests. But they are not WPT's yet. - https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/media/media-playback-while-not-visible-permission-policy-cant-play-if-hidden.html?q=third_party%2Fblink%2Fweb_tests%2Fmedia%2Fmedia-playback-while-not-visible-permission-policy-cant-play-if-hidden.html&ss=chromium%2Fchromium%2Fsrc -https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/media/media-playback-while-not-visible-permission-policy-pause-when-hidden.html

DevTrial instructions

https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/IframeMediaPause/iframe_media_pausing.md#proposed-solution-media-playback-while-not-visible-permission-policy

Flag name on about://flags

None

Finch feature name

MediaPlaybackWhileNotVisiblePermissionPolicy,AudioContextInterruptedState

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/351354996

Estimated milestones

DevTrial on desktop

133

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5082950457884672?gate=5165819033288704

Links to previous Intent discussions

Intent to Prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/PH7PR00MB1638C5FA59458CE0BBDC1FA6D5D72%40PH7PR00MB1638.namprd00.prod.outlook.com

This intent message was generated by Chrome Platform Status.

[Domenic Denicola]

Generally looks good, but there's a few things to tidy up...

On Tuesday, April 22, 2025 at 5:59:10 AM UTC+9 Chromestatus wrote:

Contact emails gabrie...@microsoft.com, ste...@microsoft.com

Explainer https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/IframeMediaPause/iframe_media_pausing.md

Specification None

Summary

Adds a "media-playback-while-not-rendered" permission policy to allow embedder websites to pause media playback of embedded iframes which aren't rendered - i.e. have their "display" property set to "none". This should allow developers to build more user-friendly experiences and to also improve the performance by letting the browser handle the playback of content that is not visible to users.

Blink component Blink>Media

TAG review None

It might be worth filing this now to get feedback early. (Not a blocker for approving the I2E.)

 

TAG review status Pending

Origin Trial documentation link https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/IframeMediaPause/iframe_media_pausing.md

Risks

Interoperability and Compatibility

This feature is still being discussed with other browser vendors and the shape and functionality might not be final.

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/1082)

WebKit: No signal (https://github.com/WebKit/standards-positions/issues/409)

Web developers: Positive (https://github.com/whatwg/html/issues/10208) The web community seems to be interested in this feature, even though we may need to iterate on the user-facing API.

Other signals:

Ergonomics

This feature will be used with other audio rendering API's, like HTMLMediaElement and Web Audio. This new behavior should only take effect if web pages explicitly opt-in by overriding the permission policy's default state. Moreover, once the permission policy is used, it should help Chromium to be more optimized by pausing audio rendering for content that is not visible for the user.

Activation

Developers need to opt-in by setting "allow" property of an iframe. For example: <iframe src="https://foo.media.com" allow="media-playback-while-not-visible 'none'"></iframe>

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

None

Goals for experimentation

Due to https://github.com/GoogleChrome/chromium-dashboard/issues/4155 (please upvote), this field gets lost when generating emails in Chrome Status. Could you copy it over for us?

 

Ongoing technical constraints

None

Debuggability

None

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)? Yes

Is this feature fully tested by web-platform-tests? Yes

We have implemented Blink webtests. But they are not WPT's yet. - https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/media/media-playback-while-not-visible-permission-policy-cant-play-if-hidden.html?q=third_party%2Fblink%2Fweb_tests%2Fmedia%2Fmedia-playback-while-not-visible-permission-policy-cant-play-if-hidden.html&ss=chromium%2Fchromium%2Fsrc -https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/media/media-playback-while-not-visible-permission-policy-pause-when-hidden.html

You can move these into web platform tests as long as you use the .tentative naming scheme. (Not blocking for the I2E.)

 

DevTrial instructions https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/IframeMediaPause/iframe_media_pausing.md#proposed-solution-media-playback-while-not-visible-permission-policy

Flag name on about://flags None

Finch feature name MediaPlaybackWhileNotVisiblePermissionPolicy,AudioContextInterruptedState

Requires code in //chrome? False

Tracking bug https://issues.chromium.org/issues/351354996

Estimated milestones DevTrial on desktop 133

This one is pretty important: can you fill in the experiment milestones?

[Gabriel Brito]

Ok. I can't seem to be able to regenerate the draft... But, I have addressed your feedback and updated the chrome status feature page where necesary. Thanks for the tip about the webtests. I will try to do it soon. Thanks for the feedback!

TAG review request: https://github.com/w3ctag/design-reviews/issues/1084

Goals for experimentation:

Gather feedback from web developers and validate that the current prototype implementation works as expected. We have added telemetry to measure how the feature is being exercised by users:

- HTMLMediaElement's: 

  - # of pauses while hidden 

  - # of pauses because got hidden during playback 

- WebAudio AudioContext's

  - # of interruptions while hidden

  - # of interruptions because got hidden during playback

Experiment milestones: M137

[Domenic Denicola]

Can you also fill in the OT end milestones? (The usual ending would be after 6 milestones, in 142, although earlier is also possible.)

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[Gabriel Brito]

Ok. Added M142 as the final milestone.

[Domenic Denicola]

Thanks! LGTM to experiment from M137-M142.

To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/9a248ee6-461e-44c8-91b6-f845a7646ecdn%40chromium.org.

[Gabriel Brito]

Thanks for reviewing!