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Update SpeechRecognitionResult with speech timing attributes #192

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Merged
alan33d merged 8 commits into from
Oct 21, 2026
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Merged

Update SpeechRecognitionResult with speech timing attributes #192

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991def1
Update SpeechRecognitionResult with audio timing attributes
alan33d Jul 14, 2026
3418472
Update audio segment time references in documentation
alan33d Aug 13, 2026
41e253a
Respond to review comments
alan33d Aug 21, 2026
2e5121d
Rename audioStartTime and audioEndTime attributes
alan33d Sep 3, 2026
e3cf78c
Address review comments: rebase on main, preserve nullable getter, fi…
alan33d Sep 11, 2026
8c38e8c
Address review: drop timestamp fuzzing bullet, clarify timeline origin
alan33d Sep 17, 2026
b7dc157
Address review: define session audio timeline in start session algori…
alan33d Oct 15, 2026
48cb721
Address review: define session audio timeline in start session algori…
alan33d Oct 15, 2026
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20 changes: 18 additions & 2 deletions index.bs
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Original file line number Diff line number Diff line change
Expand Up @@ -258,6 +258,8 @@ interface SpeechRecognitionResult {
readonly attribute unsigned long length;
getter SpeechRecognitionAlternative? item(unsigned long index);
readonly attribute boolean isFinal;
readonly attribute double speechStartTime;
readonly attribute double speechEndTime;
};

// A collection of responses (used in continuous mode)
Expand Down Expand Up @@ -382,7 +384,7 @@ See <a href="https://lists.w3.org/Archives/Public/public-speech-api/2012Sep/0072
1. If |audioTrack|'s {{MediaStreamTrack/readyState}} attribute is NOT
`"live"`, throw an {{InvalidStateError}} and abort these steps.
1. Let |requestMicrophonePermission| be `false`.
1. Run the [=start session algorithm=] with |requestMicrophonePermission|.
1. Run the [=start session algorithm=] with |requestMicrophonePermission| and |audioTrack|.
</dd>

<dt><dfn method for=SpeechRecognition>stop()</dfn> method</dt>
Expand Down Expand Up @@ -508,7 +510,7 @@ See <a href="https://lists.w3.org/Archives/Public/public-speech-api/2012Sep/0072
- Resolve <var>promise</var> with <var>status</var>.

When the <dfn>start session algorithm</dfn> with
|requestMicrophonePermission| is invoked, the user agent MUST run the
|requestMicrophonePermission| and |audioTrack| (if provided) is invoked, the user agent MUST run the
following steps:

1. If the [=current settings object=]'s [=relevant global object=]'s
Expand All @@ -529,6 +531,8 @@ following steps:
permission to use=] "`microphone`" is [=permission/"denied"=]:
1. [=Queue a task=] to [=fire an event=] named <a event for=SpeechRecognition>error</a> at [=this=] using {{SpeechRecognitionErrorEvent}} with its {{SpeechRecognitionErrorEvent/error}} attribute initialized to {{SpeechRecognitionErrorCode/not-allowed}} and its {{SpeechRecognitionErrorEvent/message}} attribute set to an implementation-defined string detailing the reason.
1. Abort these steps.
1. Begin consuming audio from the audio source (the {{MediaStreamTrack}} if one was provided, or the microphone otherwise), buffering frames if the recognition service is not yet ready.
This establishes the recognition session's <dfn>session audio timeline</dfn>, which measures elapsed audio duration in seconds starting at `0.0` at the first audio frame consumed and advancing with the duration of each subsequent audio frame consumed.
1. Once the system is successfully listening to the recognition, queue a task to
[=fire an event=] named <a event for=SpeechRecognition>start</a> at [=this=].

Expand Down Expand Up @@ -666,8 +670,20 @@ For example, some implementations may fire <a event for=SpeechRecognition>audioe
<dt><dfn attribute for=SpeechRecognitionResult>isFinal</dfn> attribute</dt>
<dd>The final boolean must be set to true if this is the final time the speech service will return this particular index value.
If the value is false, then this represents an interim result that could still be changed.</dd>

<dt><dfn attribute for=SpeechRecognitionResult>speechStartTime</dfn> attribute</dt>
<dd>A {{double}} representing the start of the speech segment corresponding to this recognition result, as an offset in seconds on the [=session audio timeline=].</dd>

<dt><dfn attribute for=SpeechRecognitionResult>speechEndTime</dfn> attribute</dt>
<dd>A {{double}} representing the end of the speech segment corresponding to this recognition result, as an offset in seconds on the [=session audio timeline=].</dd>
</dl>

<p class=note>
{{SpeechRecognitionResult/speechStartTime}} and {{SpeechRecognitionResult/speechEndTime}} are offsets on the [=session audio timeline=], not readings of a system clock.
They are therefore unaffected by audio output latency or by drift between an audio device clock and the system clock, and are identical whether recognition runs in real time or faster than real time.
Their precision is implementation-defined.
</p>

<h4 id="speechreco-resultlist">SpeechRecognitionResultList</h4>

<p>The SpeechRecognitionResultList object holds a sequence of recognition results representing the complete return result of a continuous recognition.
Expand Down
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