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ModelWhat it does
A5S Async v1
a5s-async-v1		Recorded audio (0.1 s to 10 h) → a transcript with speaker labels, word timestamps and subtitles.
REST, async jobs
A5S Small V2 Streaming
a5s-small-v2-streaming		Live audio → captions as people speak, with optional speaker labels and names.
WebSocket
AirCaps Diarization-v1
aircaps-diarization-v1		Recorded audio (0.1 s to 6 h) → who spoke when: speaker segments as JSON or RTTM.
REST, async jobs · enabled on request
AirCaps Speaker ID-v1
aircaps-speaker-id-v1		A clip (0.5 s to 2 min) → a score for each of your enrolled speakers.
REST, synchronous · enabled on request

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A5S Async v1

a5s-async-v1 · REST · batch guide · benchmarks
  • Recorded audio in any common format, from 0.1 s to 10 hours.
  • Speaker labels (speaker_0, speaker_1, …), word timestamps, utterances, SRT/VTT subtitles.
  • Optional key terms: up to 60 per transcript help it recognize names and jargon (keyterms, see Key terms).
  • Optional speaker names from your enrolled voices (speaker_identification, with AirCaps Speaker ID-v1 enabled). See Speaker names.
  • English only: language_code is en or a regional English code such as en-US, en-GB or en-IN; use the one that matches the speakers’ locale or accent.
  • Text is verbatim and lowercase without punctuation (apostrophes are kept, as in “let’s”); disfluencies (“uh”, “um”) are kept.

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A5S Small V2 Streaming

a5s-small-v2-streaming · WebSocket · streaming guide · benchmarks
Formerly A5S v2 Streaming, with id a5s-v2-streaming. The old id still works for now: a session or request that names it gets a model_deprecated warning (in ready.warnings on the WebSocket). It will be removed soon, so use a5s-small-v2-streaming.
  • Live 16 kHz mono PCM16 audio in, partial and final text out as people speak.
  • Punctuated, cased text.
  • Optional live speaker labels (diarization: true): utterances and words labelled speaker_0, speaker_1, …. See Speaker labels.
  • Optional live speaker names from your enrolled voices (speaker_identification, with speaker labels on and AirCaps Speaker ID-v1 enabled). See Speaker names.
  • Optional key terms to bias recognition toward names and jargon (custom_vocabulary, see Key terms).
  • English only: the start message’s language accepts only en.
  • Sessions last up to 30 minutes (up to 4 hours on request).

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AirCaps Diarization-v1

aircaps-diarization-v1 · REST · diarization guide · benchmarks · enabled on request
  • Who spoke when, with no transcript: speaker segments (speaker_0, speaker_1, …) with millisecond times, overlapping speech included, plus each speaker’s speaking time.
  • Finds the number of speakers itself. Works from the voices, not the words: no language_code.
  • Recorded audio in any common format, from 0.1 s to 6 hours. Results as JSON or RTTM.
  • Enabled per account: talk to sales for access.

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AirCaps Speaker ID-v1

aircaps-speaker-id-v1 · REST, synchronous · speaker ID guide · evaluation · enabled on request
  • Recognize enrolled people by voice. Enroll each person with one or more clips, then send a clip and get back a score for every enrolled speaker, best first.
  • Also names the speakers of A5S Async v1 transcripts (speaker_identification on create a transcript) and of A5S Small V2 Streaming sessions with speaker labels (live speaker names).
  • Synchronous: one clip per request, 0.5 s to 2 minutes; the scores are the response. No jobs, no polling.
  • You set the threshold: scores are similarities from -1 to 1, with no accept/reject decision. The guide has measured score ranges to start from.
  • The whole clip is compared as given. Crop clips to one person’s speech first (for example with AirCaps Diarization-v1 or a transcript’s utterances).
  • Works from the voice, not the words: no language_code.
  • Enabled per account: talk to sales for access.

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Choosing

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Languages

The transcription models support English today: language_code (A5S Async v1) takes en or a regional English code (en-US, en-GB, en-IN, …), and language (A5S Small V2 Streaming) takes en. Multilingual support is planned and will be available soon. AirCaps Diarization-v1 and AirCaps Speaker ID-v1 work from the voice and take no language.

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Access

Accounts can use A5S Async v1 and A5S Small V2 Streaming by default; an account may be limited to one of them. AirCaps Diarization-v1 and AirCaps Speaker ID-v1 are enabled per account on request. Requests to a model your account can’t use return 403 model_access_denied (streaming: an error message with that code, then close code 4403). GET /v1/account shows enabled for each model. To get access, talk to sales. GET /v1/models lists the models.