LGTM2
/Daniel
On 2026-07-27 20:45, Alex Russell wrote:
LGTM1
On Thursday, July 23, 2026 at 8:38:35 AM UTC-7 Chromestatus wrote:
*Contact emails*
[email protected], [email protected]
*Specification*
https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-renderquantumsize
<https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-renderquantumsize>
*Design docs*
/No information provided/
https://github.com/WebAudio/web-audio-api/blob/main/explainer/user-selectable-render-size.md
<https://github.com/WebAudio/web-audio-api/blob/main/explainer/user-selectable-render-size.md>
*Summary*
Adds an optional renderSizeHint to AudioContext and
OfflineAudioContext. This allows developers to customize the
WebAudio render quantum size by passing a specific integer, use
the default of 128 frames by omitting the hint or passing
"default", or request that the User-Agent select an optimal size
by specifying "hardware".
*Blink component*
Blink>WebAudio
<https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EWebAudio%22>
*Web Feature ID*
web-audio <https://webstatus.dev/features/web-audio>
*Motivation*
It is difficult and complex to write a web app when the audio
processing block size does not match with the WebAudio render
quantum size (128 sample-frames). Removing this restriction and
making it customizable on AudioContext would enable easier
development and more efficient audio processing.
*Initial public proposal*
/No information provided/
*TAG review*
/No information provided/
*TAG review status*
Issues addressed
*Origin Trial Name*
WebAudio Configurable Render Quantum
*Goals for experimentation*
Validate performance improvement gained by matching render quantum
size to software buffer sizes when using a numeric renderSizeHint.
Verify actual audio processing output is unchanged when using a
numeric renderSizeHint. We have a primary partner for this Origin
Trial, and we would like to see if the performance and ergonomics
of the API satisfy this partner's need. This partner is not going
to use the "hardware" hint, and we think that it is still valuable
to conduct an Origin Trial to gather feedback on the rest of the API.
*Chromium Trial Name*
WebAudioConfigurableRenderQuantum
*Origin Trial documentation link*
https://webaudio.github.io/web-audio-api/#dom-audiocontextoptions-rendersizehint
<https://webaudio.github.io/web-audio-api/#dom-audiocontextoptions-rendersizehint>
*WebFeature UseCounter name*
kWebAudioRenderSizeHint
*Risks*
*Interoperability and Compatibility*
Low. The feature is already specified.
/Gecko/: No
signal (https://github.com/mozilla/standards-positions/issues/1407
<https://github.com/mozilla/standards-positions/issues/1407>) A
Firefox developer wrote the specification change
(https://github.com/WebAudio/web-audio-api/pull/2469
<https://github.com/WebAudio/web-audio-api/pull/2469>).
/WebKit/: No
signal (https://github.com/WebKit/standards-positions/issues/662
<https://github.com/WebKit/standards-positions/issues/662>)
/Web developers/:
Positive (https://github.com/WebAudio/web-audio-api/issues/1503
<https://github.com/WebAudio/web-audio-api/issues/1503>) Developers
have requested a way to increase the render quantum size, and are
looking forward to the feature being implemented.
/Other signals/:
*Ergonomics*
An identified use case of this feature is to match buffer sizes
used by other Chromium audio APIs, in order to improve performance.
*Activation*
There is an ongoing privacy discussion about how to mitigate
fingerprinting concerns around the "hardware" hint
(https://github.com/WebAudio/web-audio-api/issues/2659
<https://github.com/WebAudio/web-audio-api/issues/2659>). The
"hardware" hint as implemented in Chromium currently will always
return the default 128 render quantum size, which exposes no user
information. This is allowed by the spec, which says "It is a hint
that might not be honored."
*Security*
There is concern that a very low render quantum size could allow
an AudioWorklet to create a high-resolution timer, but very high
sample rates are already allowed and have a similar risk so the
marginal change in security is probably low.
*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?
Low. The change is to ship a new API.
*Debuggability*
It may be worth exposing the render quantum size value in the
DevTools WebAudio pane, similar to sample rate.
*Will this feature be supported on all six Blink platforms
(Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?*
Yes
All supported platforms have mechanisms to implement this feature.
*Is this feature fully tested by web-platform-tests
<https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?*
Yes
https://wpt.fyi/results/webaudio/the-audio-api/the-audiocontext-interface/audiocontext-rendersizehint.html
<https://wpt.fyi/results/webaudio/the-audio-api/the-audiocontext-interface/audiocontext-rendersizehint.html>
https://wpt.fyi/results/webaudio/the-audio-api/the-offlineaudiocontext-interface/offlineaudiocontext-rendersizehint.html
<https://wpt.fyi/results/webaudio/the-audio-api/the-offlineaudiocontext-interface/offlineaudiocontext-rendersizehint.html>
*Flag name on about://flags*
N/A (launch with --enable-features=WebAudioConfigurableRenderQuantum)
*Finch feature name*
WebAudioConfigurableRenderQuantum
*Rollout plan*
Will ship enabled for all users
*Requires code in //chrome?*
False
*Tracking bug*
https://crbug.com/40637820
*Launch bug*
https://launch.corp.google.com/launch/4416924
<https://launch.corp.google.com/launch/4416924>
*Measurement*
UseCounters: WebAudioRenderSizeHint, WebAudioRenderQuantumSize
*Availability expectation*
We expect that Firefox will implement the feature independently at
some point.
*Adoption expectation*
We expect that specific partners will use this functionality
immediately upon its launch in Chrome.
*Adoption plan*
We are in communication with partners, and also in communication
with Mozilla via the Audio Working Group.
*Non-OSS dependencies*
Does the feature depend on any code or APIs outside the Chromium
open source repository and its open-source dependencies to function?
No.
*Estimated milestones*
Shipping on desktop 153
Origin trial desktop first 145
Origin trial desktop last 151
Origin trial extension 1 end milestone 151
Origin trial extension 2 end milestone 153
Origin trial extension 3 end milestone 152
DevTrial on desktop 145
Shipping on Android 153
Origin trial Android first 145
Origin trial Android last 151
Shipping on WebView 153
Origin trial WebView first 145
Origin trial WebView last 151
*Anticipated spec changes*
Open questions about a feature may be a source of future web
compat or interop issues. Please list open issues (e.g. links to
known github issues in the project for the feature specification)
whose resolution may introduce web compat/interop risk (e.g.,
changing to naming or structure of the API in a
non-backward-compatible way).
https://github.com/WebAudio/web-audio-api/issues/2663
<https://github.com/WebAudio/web-audio-api/issues/2663>
https://github.com/WebAudio/web-audio-api/issues/2664
<https://github.com/WebAudio/web-audio-api/issues/2664>
*Link to entry on the Chrome Platform Status*
https://chromestatus.com/feature/5078190552907776?gate=5074255557165056
<https://chromestatus.com/feature/5078190552907776?gate=5074255557165056>
*Links to previous Intent discussions*
Intent to Prototype:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/688d3254.2b0a0220.361edb.0299.GAE%40google.com
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/688d3254.2b0a0220.361edb.0299.GAE%40google.com>
Intent to Experiment:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CA%2BuAeqS%3DygCo2wPaf0Cfo%2B%2BdEoHGWx%2Byc4%2BfO84U%2B_5hQqOvYg%40mail.gmail.com
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CA%2BuAeqS%3DygCo2wPaf0Cfo%2B%2BdEoHGWx%2Byc4%2BfO84U%2B_5hQqOvYg%40mail.gmail.com>
Intent to Extend Experiment 1:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/69dd7ab5.050a0220.c8e20.0171.GAE%40google.com
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/69dd7ab5.050a0220.c8e20.0171.GAE%40google.com>
Intent to Extend Experiment 2:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a5fe800.77f2aaf9.1be956.027f.GAE%40google.com
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a5fe800.77f2aaf9.1be956.027f.GAE%40google.com>
Intent to Extend Experiment 3:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a3319c8.3af95f39.17d45c.005e.GAE%40google.com
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a3319c8.3af95f39.17d45c.005e.GAE%40google.com>
This intent message was generated by Chrome Platform Status
<https://chromestatus.com>.
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