Contact emails
fhernqv...@google.com, o...@google.com, hongc...@google.com, 
agpa...@google.com, gui...@google.com


Explainer
https://github.com/WICG/web_audio_playout


Specification
https://wicg.github.io/web_audio_playout


Summary

The AudioContext.playoutStats API allows an application to measure the quality 
and latency of audio playout using WebAudio.



Blink component
Blink>WebAudio


TAG review
Early TAG review request: https://github.com/w3ctag/design-reviews/issues/939


TAG review status
Issues addressed


Origin Trial Name
Playout Statistics API for WebAudio


Chromium Trial Name
AudioContextPlayoutStats


Origin Trial documentation link
https://github.com/WICG/web_audio_playout


WebFeature UseCounter name
kAudioContextPlayoutStats


Risks




Interoperability and Compatibility

None


Gecko: No signal

WebKit: No signal

Web developers: Positive 
(https://github.com/WICG/proposals/issues/142#issuecomment-1981012486)

Other signals:


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




Reason this experiment is being extended

Since the last extension, the Privacy WG have reviewed the API, and noted some 
security concerns[1]. We have discussed them and agreed on a set of 
mitigations, given which the Privacy WG have indicated that they will approve 
the API[2]. If you don't have access to the slack thread, you can read the 
relevant messages here (shared with Blink API-owners)[3] We have updated the 
spec with a formal algorithm which includes the mitigations as well as a 
Privacy & Security considerations section discussing the concerns. [4] We are 
requesting this Origin Trial extension to give us time to get the Privacy WG's 
final approval on the new version of the spec, and present it to the Audio WG 
(who are positive towards the API when it was presented at TPAC but want 
approval from the Privacy WG before adopting it). [1] 
https://github.com/WICG/web_audio_playout/issues/4 [2] 
https://w3ccommunity.slack.com/archives/C06BB1JR528/p1747683821732619?thread_ts=1744909746.069129&cid=C06BB1JR528
 [3] 
https://docs.google.com/document/d/1Mg-O-YX4xiFJ2qtvjRDL_F5SbKf74TJFYYQnTCE5QrU/edit?tab=t.0
 [4] https://wicg.github.io/web_audio_playout/



Reason this experiment is being extended

We need additional time to work with Privacy WG to address their concerns. 
Since the origin trial started, we have made the following progress: * The API 
was presented at TPAC, and got a positive reaction from Audio WG. However, they 
wanted to hear the Privacy WG's input, and that we should ask the internal 
privacy/security reviewers why the API is ok while the similar RenderCapacity 
API was not ok. ( 
https://docs.google.com/document/d/1QiBmVZb51ATyai_TTbkMnq25zaQOzVNxNIsPJZ8sdUE/edit?tab=t.0#heading=h.el9c5z4prh05
 ) * We have presented the API to the Privacy WG and they have discussed it 
(https://github.com/w3c/privacywg/blob/main/minutes/privacywg-20250417.md#webaudio)
 . We are now having an active discussion with them about how we can address 
their concerns. * Google-internal privacy/security reviewers have reaffirmed 
that the API is ok, and safer than the RenderCapacity API. * We have added wpt 
tests for the API.



Ongoing technical constraints

None.



Debuggability

Can be tested by creating an AudioContext and evaluating context.playoutStats 
in the console.



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
https://wpt.fyi/results/webaudio/the-audio-api/the-audiocontext-interface/audiocontext-playoutstats.html?label=experimental&label=master&aligned
 These will be updated if the API shape changes.



Flag name on about://flags
None


Finch feature name
AudioContextPlayoutStats


Requires code in //chrome?
False


Estimated milestones


Origin trial desktop first 131

Origin trial desktop last 136

Origin trial extension 1 end milestone 142

Origin trial extension 2 end milestone 139

DevTrial on desktop 129




Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5172818344148992?gate=5107124824440832


Links to previous Intent discussions
Intent to Prototype: 
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACazmWW4MYVa_iGjN%3DK4O9B1DE3rt4_2Vkqnq6sKswHFjn6BzQ%40mail.gmail.com
Intent to Experiment: 
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACazmWWV6S6Ba%3Dd%3DgvjhERm1OnPyBMRJx5fbkP%3Df9zb3k%3DrNDA%40mail.gmail.com
Intent to Extend Experiment 2: 
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACazmWVkWb8DJM_aCRGOFpskBs-7h%3DO_yggKc3YBUkiieEO-UA%40mail.gmail.com



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