Speech-to-text

Speech-to-text has separate completed-recording and live-streaming interfaces.

Completed recordings

The selected API service is ctx.apiSpeechToText. It also registers with DSH's built-in speechToText registry when that registry is enabled, so DSH Voice Input can use it alongside built-in providers.

const transcript = await ctx.apiSpeechToText.transcribe(
  {audio: wavBytes, language: 'en'},
  signal,
)

The result contains text, recording duration in audioSeconds, and request duration in inferenceSeconds. Use language auto to omit a language hint. The OpenAI-compatible provider uploads the bytes as recording.wav to POST /audio/transcriptions.

Live streaming

ctx.streamingSpeechToText exists only when the selected provider implements live transcription. Inject it as optional.

const session = await ctx.streamingSpeechToText.startStreaming({
  language: 'en',
  format: 'pcm16',
  signal,
})

for await (const event of session.events) {
  if (event.type === 'delta') showPartial(event.text)
  if (event.type === 'final') acceptTranscript(event.text)
  if (event.type === 'error') throw event.error
}

Send audio with session.append(chunk), call session.commit() to request transcription of the current buffer, and call session.close() when finished.

The OpenAI-compatible implementation uses the Realtime transcription WebSocket. Its formats are pcm16 (24 kHz mono by default), g711_ulaw, and g711_alaw. It also accepts a vocabulary/style prompt and a per-session model override. Live sessions are long-lived and do not pass through the request concurrency gate.