Intent to Prototype: SpeechRecognitionResult Timestamps (WebSpeech API)

[Chromestatus]

Contact emails

alan...@chromium.org

Explainer

https://github.com/WebAudio/web-speech-api/blob/main/explainers/speech-recognition-result-timestamps.md

Specification

https://github.com/WebAudio/web-speech-api/pull/192

Summary

The Web Speech API currently does not allow developers to associate the transcribed text with specific segments of the audio source, making it difficult to map the generated text to the timeline or determine on-device transcription latency. We propose adding audioStartTime and audioEndTime (DOMHighResTimeStamp?) attributes on the SpeechRecognitionResult interface.

Blink component

Blink>Speech

Web Feature ID

speech-recognition

Motivation

Web applications are increasingly adopting on-device Automatic Speech Recognition (ASR) via the Web Speech API (SpeechRecognition) to enhance user privacy and lower backend processing costs. However, the WebSpeech API operates as a "black box" regarding local processing delays: 1. Lack of Latency Tracking & Backend Recovery: When client devices with constrained CPU/GPU resources struggle to process audio in real time, significant transcription lag accumulates between when audio was spoken and when recognition results are emitted. Web applications have no web-exposed timing metrics to programmatically detect this lag or trigger an optional failover to a high-quality cloud ASR backend provider, resulting in degraded user experiences (e.g., stale or delayed captions in live video conferencing tools). 2. Timeline Association: Developers cannot readily map recognized transcript text to specific segments of the source audio timeline, creating challenges for automated subtitle cue alignment and media editing tools.

Initial public proposal

https://github.com/WebAudio/web-speech-api/issues/191

Goals for experimentation

None

Requires code in //chrome?

False

Tracking bug

https://crbug.com/528037568

Estimated milestones

No milestones specified

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5811907077472256?gate=5917118676729856

This intent message was generated by Chrome Platform Status.