|
const { createClient, LiveTranscriptionEvents } = require("@deepgram/sdk"); |
|
const EventEmitter = require("events"); |
|
const crypto = require("crypto"); |
|
|
|
class TranscriptionClient extends EventEmitter { |
|
constructor() { |
|
super(); |
|
this.deepgramStream = null; |
|
this.deepgramSessionId = null; |
|
this.currentTranscript = ""; |
|
this.currentDiarization = {}; |
|
this.releaseTimeout = null; |
|
this.killTimeout = null; |
|
this.releaseThresholdMS = 4000; |
|
this.killThresholdMS = 1000 * 60 * 2; |
|
this.diarize = false; |
|
this.speakerLabels = {}; |
|
} |
|
|
|
startTranscriptionStream(language) { |
|
console.log("started deepgram"); |
|
const localSessionId = crypto.randomUUID(); |
|
this.deepgramSessionId = localSessionId; |
|
const deepgram = createClient(process.env.DEEPGRAM_API_KEY); |
|
this.deepgramStream = deepgram.listen.live({ |
|
model: "nova-2", |
|
punctuate: true, |
|
language, |
|
interim_results: true, |
|
diarize: this.diarize, |
|
smart_format: true, |
|
endpointing: "2", |
|
}); |
|
|
|
this.deepgramStream.on(LiveTranscriptionEvents.Error, (err) => { |
|
console.log("Deepgram error: ", err); |
|
}); |
|
|
|
this.deepgramStream.on(LiveTranscriptionEvents.Warning, (err) => { |
|
console.log("Deepgram error: ", err); |
|
}); |
|
|
|
this.deepgramStream.on(LiveTranscriptionEvents.Open, () => { |
|
this.resetKillTimeout(); |
|
|
|
this.deepgramStream.on( |
|
LiveTranscriptionEvents.Transcript, |
|
async (data) => { |
|
try { |
|
const response = data.channel.alternatives[0]; |
|
const text = response?.transcript || ""; |
|
if (text.length > 1) { |
|
clearTimeout(this.releaseTimeout); |
|
this.releaseTimeout = setTimeout(() => { |
|
this.releaseTranslations(true); |
|
}, this.releaseThresholdMS); |
|
this.resetKillTimeout(); |
|
} |
|
|
|
|
|
if (response.transcript && data.is_final) { |
|
|
|
const words = data.channel?.alternatives[0]?.words || []; |
|
words.forEach(({ punctuated_word, speaker, start, end }) => { |
|
if (!this.currentDiarization[speaker]) |
|
this.currentDiarization[speaker] = ""; |
|
this.currentDiarization[speaker] += " " + punctuated_word; |
|
}); |
|
this.emit("transcript", text) |
|
this.currentTranscript += " " + text; |
|
this.releaseTranslations(); |
|
|
|
} |
|
} catch (err) { |
|
console.log( |
|
"TranscribeTranslate.LiveTranscriptionEvents.Transcript:", |
|
err |
|
); |
|
} |
|
} |
|
); |
|
}); |
|
return this.deepgramSessionId; |
|
} |
|
|
|
resetKillTimeout = () => { |
|
clearTimeout(this.killTimeout); |
|
this.killTimeout = setTimeout( |
|
() => this.endTranscriptionStream(), |
|
this.killThresholdMS |
|
); |
|
}; |
|
|
|
releaseTranslations = async (triggeredByPause = false) => { |
|
try { |
|
let segment = ""; |
|
let speaker = null; |
|
if (this.diarize) { |
|
const processedSpeakers = Object.entries(this.currentDiarization).map( |
|
([speaker, transcript]) => ({ |
|
...this.checkShouldSegment(transcript, triggeredByPause ? 5 : 50), |
|
speaker, |
|
}) |
|
); |
|
const chosen = processedSpeakers.find((s) => s.canRelease); |
|
if (!chosen) return; |
|
this.currentDiarization = { [chosen.speaker]: chosen.secondPart }; |
|
segment = chosen.firstPart; |
|
speaker = this.getSpeakerLabel(chosen.speaker); |
|
} else { |
|
const { canRelease, firstPart, secondPart } = this.checkShouldSegment( |
|
this.currentTranscript, |
|
triggeredByPause ? 5 : 50 |
|
); |
|
if (!canRelease) return; |
|
this.currentTranscript = secondPart; |
|
segment = firstPart; |
|
} |
|
|
|
|
|
this.emit("translation", segment) |
|
|
|
|
|
this.lastEmittedSpeaker = speaker; |
|
} catch (err) { |
|
console.log("TranscribeTranslate.releaseTranslations:", err); |
|
} |
|
}; |
|
|
|
endTranscriptionStream() { |
|
try { |
|
clearTimeout(this.releaseTimeout); |
|
clearTimeout(this.killTimeout); |
|
if (!this.deepgramStream) return; |
|
this.deepgramStream.finish(); |
|
this.deepgramStream = null; |
|
this.currentTranscript = ""; |
|
} catch (err) { |
|
console.log("Failed to end deepgram stream", err); |
|
} |
|
} |
|
|
|
checkShouldSegment = (str, minCharLimit = 25) => { |
|
let firstPart = ""; |
|
let secondPart = ""; |
|
const punct = new Set([".", "!", "?", "。", "۔"]); |
|
for (let i = 0; i < str.length; i += 1) { |
|
const char = str[i]; |
|
if (i > minCharLimit) { |
|
if (punct.has(char)) { |
|
firstPart = str.slice(0, i + 1); |
|
secondPart = str.slice(i + 1); |
|
} |
|
} |
|
} |
|
|
|
return { canRelease: !!firstPart.length, firstPart, secondPart }; |
|
}; |
|
|
|
send(payload) { |
|
try { |
|
if (!this.deepgramStream) return; |
|
if (this.deepgramStream.getReadyState() === 1) { |
|
this.deepgramStream.send(payload); |
|
} |
|
} catch (err) { |
|
console.log("Failed to start deepgram stream", err); |
|
} |
|
} |
|
} |
|
|
|
module.exports = TranscriptionClient; |
|
|