OfflineAudioContext Incremental Rendering

[gabrielsanbrito]

This PR proposes changes to the Web Audio spec to enable rendering audio from OfflineAudioContexts in chunks.

Github issue: #2445
Feature explainer: https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/OfflineAudioContext/explainer.md

---

💥 Error: 422 Unprocessable Entity 💥

PR Preview failed to build. (Last tried on Jun 5, 2026, 10:37 PM UTC).

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🚨 Spec Generator - Spec Generator is the web service used to build bikeshed/ReSpec specs

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Error output:

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        "lineNum": "3867:9",
        "messageType": "fatal",
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        "lineNum": "3867:9",
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[gabrielsanbrito]

@hoch @padenot @mjwilson-google, this is the first draft for OfflineAudioContext incremental rendering. PTAL when you have some time.

While writing this, we had some open questions that might be better to discuss here:

• In this draft I am proposing using Infinity to denote the undefined-length render scenario. However, OfflineAudioContextOptions.length is currently an unsigned long, which cannot be Infinity. What would be preferrable?
  • Swap all Infinity usage for null; or
  • Convert OfflineAudioContextOptions.length to an union type like (long | float) that only accept the Infinity value for float.
• When OfflineAudioContextOptions.length is Infinity and chunksSize is not provided to startRendering(), chunkSize defaults to the render quantum size. But the render quantum size is very small. Maybe, should we consider a more optimal default?
• Should OfflineAudioContextOptions.length be a multiple of chunkSize? I am assuming it doesn't need to.

(unfortunately, there is no preview available, but I think there might be something actually broken in the repo's CI pipeline)