RealtimeTenVad (TEN VAD – Realtime, Node.js)

Tiny realtime VAD wrapper around a WASM backend. Feed it 16 kHz mono float audio (Float32Array in [-1,1]), and get start/end callbacks for detected speech.

Adapted from TEN-VAD.

Installation and Usage

``sh
npm install realtime-ten-vad
`

Require and use as follows:

`js
// Use main export (index.js):
const { RealtimeTenVad } = require('realtime-ten-vad');

const vad = await RealtimeTenVad.new({
// Callbacks
onSpeechStart() { / speech just began / },
onSpeechEnd(seg) { / seg: Float32Array @ 16 kHz with pre/post padding / },
onVADMisfire() { / segment shorter than minSpeechMs / },

// Tunables (all optional; shown with defaults)
positiveSpeechThreshold: 0.6,
negativeSpeechThreshold: 0.4,
minSpeechFrames: 3,
minSilenceFrames: 8,
probSmoothing: 0.2,
energyGateDb: null,
preEmphasis: 0.0,
preSpeechPadMs: 80,
postSpeechPadMs: 160,
minSpeechMs: 150,
});

// stream audio
vad.processAudio(float32Chunk);
// when you're done:
vad.flush();
vad.destroy();
`

Options (what they do)

$3

* onSpeechStart(): void
Fired once when the VAD transitions into speech (after the minimum entry condition is met). No arguments.
* onSpeechEnd(seg: Float32Array): void
Fired when a speech segment is finalized (after trailing silence + post-pad). seg is 16 kHz mono, includes configured pre/post padding.
* onVADMisfire(): void
Fired instead of onSpeechEnd if the detected segment’s duration is < minSpeechMs.

$3

| Option | Type (range) | Default | Meaning & tips |
|-------------------------- | -------------------:| -------:| -------------------------------------------------------------------------------------------------------------------- |
| positiveSpeechThreshold | number (0..1) | 0.6 | Probability threshold to enter speech when in silence. Higher = stricter start |
| negativeSpeechThreshold | number (0..1) | 0.4 | Probability threshold in speech, keeps speech “latched” until confidence < this value. Lower = more tolerant. |
| (hysteresis) | — | — | If negative > positive, values are automatically swapped to ensure correct behavior |
| minSpeechFrames | number (frames) | 3 | Minimum consecutive voice frames (each 256 samples ≈ 16 ms) needed for speech start. 3 ≈ 48 ms. |
| minSilenceFrames | number (frames) | 8 | Minimum consecutive non-voice frames to consider speech ended |
| probSmoothing | number (0..1) | 0.2 | EMA smoothing of VAD probability. 0 = reacts instantly; →1 = slow. |
| energyGateDb | number \| null | null | RMS energy gate in dBFS. Frames below this are treated as silence; null disables. |
| preEmphasis | number (~0..0.97) | 0.0 | Pre-emphasis for VAD only. Does not affect callback audio. |
| preSpeechPadMs | number (ms) | 80 | Leading context included at the start of each segment |
| postSpeechPadMs | number (ms) | 160 | Trailing context appended after speech ends (collected during silence) prior to segment finalize |
| minSpeechMs | number (ms) | 150 | Segments shorter than this are considered misfires → onVADMisfire |

Notes & expectations

* Input: processAudio(Float32Array) at 16 kHz mono, range [-1, 1]. Anything else throws.
* Framing: Fixed hop of 256 samples (≈16 ms) internally.
* System deps: For microphone recording, you may require platform tools (Linux: arecord/sox, macOS: sox).
* Lifecycle: Call flush() to close in-progress segments (adds post-pad) before destroy().
* CLI demo/test: See test.js and record.js`. System microphone permissions/tools required.