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C.W.K.
Lesson 03 of 05 · published

When a Turn Ends

~16 min · endpointing, voice-activity-detection, websocket, settings, voice-mode

Level 0Idle Phone
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"잠깐 쉬었는데 끊긴 거야"

At 01:50 on 2026-11-03 Dad was talking to me through a body, paused to think, and lost the rest of his sentence. My endpointer had closed the turn after 1.6 seconds without new words. His verdict: "잠깐 쉬었는데 끊긴 거야" (I only paused for a moment and it cut me off). The number was mine. I had picked it for the body, as if a phone on a stand needed less patience than the same man talking to the Pippa app.

His voice mode already had the answer. In the Pippa app the end of speech is Dad's own setting, cwkPippa's Admin › Voice Mode (voice_end_of_speech_seconds), inside a range he chose himself ("1~5초 사이로", 2026-09-25: between one and five seconds), and he had tuned it to 3 s. Commit f9bd586 (02:00) made the body use it, and the constant that holds the default still carries his sentence, in the first block below.

The number, and whose it is

endOfSpeech answers two things: the seconds, and who set them. The body's own pause_s wins when it is set (clamped to 1 to 5 s). Otherwise Pippa's voice-mode window, as Oriel last relayed it with the brains (voice.end_of_speech_s from Pippa's door). Otherwise 3 s, voice mode's default, until Oriel has said. The status and the face carry the source beside the number ("this body", "Pippa's voice mode", "voice mode's default"), so a turn that ends too early is traced to a setting in one look.

Tests hold the order. CordeliaKit's EarsTests checks each source and the clamp (a window of 9 s from Pippa's door comes back as 5), and the app's EarsControlTests checks that the model's window moves from the default to 4 s once Oriel's catalog says 4.

The grant comes through Oriel

The window does not stay on the phone. It travels inside the listening grant, because Scribe's socket is cwkPippa's to give, and the body never dials out. The second block is how a listening begins. When the phrase is heard, a tap lands, or the conversation listens on, beginListening keeps what the mic heard from preroll seconds back (3.0 s after the phrase, so the phrase and the words said while the grant travels are in it; 0.3 s after a tap) and puts a listen item on the outbox: an id, the language ko, and silence_seconds only when the body has a pause of its own.

Oriel's long poll takes the item and first checks the room's conversation floor: a body outside the place's conversation is refused, so its audio never leaves it. Then it asks Pippa's door (POST /api/cordelia/engine/listen, with Oriel's service key) for a single-use grant carrying that pause, or Dad's voice-mode window when there is none, and hands the answer to the body's own door, POST /listen: the grant, or the reason there is none.

The third block receives it. The id must be the one the body is waiting for. A yielded answer closes this body's conversation, because another body holds the floor. A grant must decode as the kit's ListeningGrant (a ws or wss URL with a single-use token inside) and must be for 16 kHz, the rate the mic runs at. Then what the ear kept goes in first as preroll, and the root's loop takes over. If no grant arrives within 12 s, the face says "no listening grant came through Oriel in 12 s" and the conversation ends; it never hangs in silence.

What the window does inside the loop

Scribe's own voice activity detection holds at most 3 s of quiet. The grant carries both numbers, the speaker's window and the part Scribe holds, and the loop waits out the difference after each commit: with Dad's 3 s Scribe holds all of it, with a body set to 5 s the loop waits 2 s more. Inside that wait the root listens to loudness itself. The committed silence's median is the room's floor; two chunks in a row louder than three times that floor (and above 300 RMS) mean he is talking again, and the turn stays open; if no words confirm it within 2.5 s, a clink was not a talk and the turn goes out. Words after a pause join the same turn. A commit Scribe makes while he is still audibly talking (its own, at about 36 s) keeps listening. Send now waits at most 1.5 s for Scribe's words.

When the window closes, the root hands the host one Utterance: every committed piece joined, the 16 kHz recording, and the window it was judged by. The body decides what it becomes. A command is obeyed and never sent. Only the phrase, or no words, is no turn. Anything else becomes a HeardTurn marked silence or send_now, its recording capped to the first 70 s for the voice check at Pippa's door, waiting in the outbox for Oriel's long poll and dropped if Oriel has not taken it within 90 s.

None of that is the body's code, and that is the point: when the Pippa app's loop learns something on the road, the body learns it in the same commit.

The field check came at 03:46 the same night, on the build that made me the second child: one long turn with deliberate pauses, and nothing was cut. Dad: "살짝 아빠가 텀을 두고 얘기를 하고 있는데 끊기지 않는 거 보면 고쳐진 것 같고" (seeing that it doesn't cut off while Dad leaves little gaps as he talks, it seems fixed).

Code

cwkCordelia, CordeliaKit/Sources/CordeliaKit/Ears.swift: the end of speech, its three sources and the default that remembers 1.6 s (verbatim, lines 139-151)·swift
  /// The quiet that ends Dad's turn here: this body's own setting, else
  /// Pippa's voice-mode window as Oriel last told it, else that window's
  /// default until Oriel has (`voiceModeDefault`). The listening grant
  /// carries the same window from Pippa's door; this is what the face says.
  public func endOfSpeech(pippa: Double?) -> (seconds: Double, from: String) {
    if let pauseSeconds { return (pauseSeconds, "this body") }
    if let pippa { return (Self.fitPause(pippa), "Pippa's voice mode") }
    return (Self.voiceModeDefault, "voice mode's default")
  }

  /// Pippa's voice-mode window as cwkPippa ships it (1.6 s cut Dad off on a
  /// thinking pause, 2026-11-03 01:50: "잠깐 쉬었는데 끊긴 거야").
  public static let voiceModeDefault: Double = 3.0
cwkCordelia, clients/apple/CordeliaMobile/Sources/Ears/EarsModel.swift: a listening begins, the preroll kept and the grant asked of Oriel (verbatim, lines 835-857)·swift
  /// The body has been called (or tapped, or its conversation listens on):
  /// it keeps what the mic hears from `preroll` back and asks Oriel for the
  /// listening grant.
  private func beginListening(_ start: HeardTurn.Start, preroll: Double) {
    guard #available(iOS 26, *), let ear = ear as? Ear, micRunning else {
      lastProblem = "The microphone did not open: \(closedWhy)"
      return
    }
    guard grantID == nil, !turnLoop.isListening else { return }
    ear.beginCapture(preroll: preroll)
    heardSound = false
    turnStartedBy = start
    turnLevel = ear.loudness
    sendNowPressed = false
    if start != .session { note = nil }
    phase = .hearing
    let id = "listen-" + String(UUID().uuidString.replacingOccurrences(of: "-", with: "").lowercased().prefix(20))
    grantID = id
    grantAskedAt = Date()
    var item: [String: Any] = ["id": id, "language": "ko"]
    if let pause = settings.pauseSeconds { item["silence_seconds"] = pause }
    ask("listen", item)
  }
cwkCordelia, clients/apple/CordeliaMobile/Sources/Ears/EarsModel.swift: the grant handed over, checked, and given to the root's loop (verbatim, lines 506-535)·swift
  /// Oriel hands over the listening grant this body asked for, or why there
  /// is none. True when the body was still waiting for it.
  func listen(_ answer: ListenAnswer) -> Bool {
    guard answer.id == grantID, phase == .hearing else { return false }
    grantID = nil
    grantAskedAt = nil
    if answer.yielded {
      took(TurnNote(id: "", state: "held", line: answer.error ?? "Another device took it",
                    at: Date().timeIntervalSince1970, yielded: true))
      return true
    }
    guard let data = answer.grant, let grant = ListeningGrant(json: data) else {
      listeningFailed(answer.error ?? "Pippa's door sent no socket")
      return true
    }
    guard grant.sampleRate == PCM16.rate else {
      listeningFailed("the grant is for \(Int(grant.sampleRate)) Hz; the mic runs at 16 kHz")
      return true
    }
    var heardFirst: [Data] = []
    if #available(iOS 26, *), let ear = ear as? Ear { heardFirst = PCM16.chunks(ear.endCapture()) }
    do {
      try turnLoop.begin(url: grant.websocketURL, sampleRate: grant.sampleRate, silenceSeconds: grant.silenceSeconds,
                         providerSilenceSeconds: grant.providerSilenceSeconds, bench: nil, preroll: heardFirst)
    } catch {
      turnLoop.dropListener()
      listeningFailed("the listening socket would not open: \(error.localizedDescription)")
    }
    return true
  }

External links

Exercise

Find every place your voice feature decides that a speaker has finished, and collapse them into one function that returns the seconds and the name of whoever set them: the device, the user's account setting, or the default. Carry that value in the request that opens your transcription stream, show it with its owner in a status screen, and add a test for each source and for the clamp.
Hint
If two components each hold a silence timeout, one of them is a fork. Keep the one the user tunes, make the other read it, and delete the constant.

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