const WakewordDetector = require('@hakerzp/node-personal-wakeword')
const Mic = require('mic')
const Stream = require('stream')
async function main() {
// Create a new wakeword detection engine
let detector = new WakewordDetector({
/*
sampleRate: 16000,
bitLength: 16,
frameShiftMS: 10.0,
frameLengthMS: 30.0, // Must be a multiple of frameShiftMS
vad: true, // Use VAD detection
vadMode: WakewordDetector.VadMode.AGGRESSIVE, // See node-vad modes
vadDebounceTime: 500,
band: 5, // DTW window width
ref: 0.22, // See Snips paper for explanation about this parameter
preEmphasisCoefficient: 0.97, // Pre-emphasis ratio
*/
threshold: 0.5 // Default value
})
// *****
// KEYWORD MANAGEMENT
// Add a new keyword using multiple "templates"
await detector.addKeyword('alexa', [
// WAV templates (trimmed with no noise!)
'./keywords/alexa1.wav',
'./keywords/alexa2.wav',
'./keywords/alexa3.wav'
], {
// Options
disableAveraging: true, // Disabled by default, disable templates averaging (note that resources consumption will increase)
threshold: 0.52 // Per keyword threshold
})
// Keywords can be enabled/disabled at runtime
detector.disableKeyword('alexa')
detector.enableKeyword('alexa')
// *****
// EVENTS
// The detector will emit a "ready" event when its internal audio frame buffer is filled
detector.on('ready', () => {
console.log('listening...')
})
// The detector will emit an "error" event when it encounters an error (VAD, feature extraction, etc.)
detector.on('error', err => {
console.error(err.stack)
})
// The detector will emit a "vad-silence" event when no voice is heard
detector.on('vad-silence', () => {
console.log('Hearing silence...')
})
// The detector will emit a "vad-voice" event when it hears a voice
detector.on('vad-voice', () => {
console.log('Hearing voices...')
})
// The detector will emit a "data" event when it has detected a keyword in the audio stream
/* The event payload is:
{
"keyword" : "alexa", // The detected keyword
"score" : 0.56878768987, // The detection score
"threshold" : 0.5, // The detection threshold used (global or keyword)
"frames" : 89, // The number of audio frames used in the detection
"timestamp" : 1592574404789, // The detection timestamp (ms)
"audioData" : <Buffer> // The utterance audio data (can be written to a file for debugging)
}
*/
detector.on('data', ({keyword, score, threshold, timestamp}) => {
console.log(`Detected "${keyword}" with score ${score} / ${threshold}`)
})
// Note that as the detector is a transform stream the standard "data" event also works...
// I just added the "keyword" event for clarity :)
// *****
// STREAMS
// As an alternative to events, the detector is a transform stream that takes audio buffers in and output keyword detection payload
const detectionStream = new Stream.Writable({
objectMode: true,
write: (data, enc, done) => {
// `data` is equivalent to "data" event payload
console.log(data)
done()
}
})
detector.pipe(detectionStream)
// *****
// Create an audio stream from an audio recorder (arecord, sox, etc.)
let recorder = Mic({
channels : detector.channels, // Defaults to 1
rate : detector.sampleRate, // Defaults to 16000
bitwidth : detector.bitLength // Defaults to 16
})
let stream = recorder.getAudioStream()
// Pipe to wakeword detector
stream.pipe(detector)
recorder.start()
// Destroy the recorder and detector after 10s
setTimeout(() => {
stream.unpipe(detector)
stream.removeAllListeners()
stream.destroy()
stream = null
recorder = null
detector.removeAllListeners()
detector.destroy()
detector = null
}, 10000)
}
main()