node-vad
This is a stripped down version of this library (https://github.com/voixen/voixen-vad). Thank you very much!
Voice Activity Detection library
Voice Activity Detection based on the method used in the upcoming WebRTC HTML5 standard. Extracted from Chromium for stand-alone use as a library.
Supported sample rates are:
- 8000Hz
- 16000Hz*
- 32000Hz
- 48000Hz
*recommended sample rate for best performance/accuracy tradeoff
Installation
API
new VAD(mode)
Create a new VAD
object using the given mode.
.processAudio(samples, samplerate)
Analyse the given samples (Buffer
object containing 16bit signed values) and notify the detected voice
event via promise.
.processAudioFloat(samples, samplerate)
Analyse the given samples (Buffer
object containing 32bit normalized float values) and notify the detected voice
event via promise.
static .createStream(options)
Create an stream for voice activation detection.
Options
mode: VADModeNORMAL // VAD mode, see above audioFrequency: 16000 // Audiofrequency, see above debounceTime: 1000 // Time for debouncing speech active state, default 1 second
Stream output example:
time: 14520 // Current seek time in audio audioData: <Buffer> // Original audio data speech: state: true // Current state of speech start: false // True on chunk when speech starts end: false // True on chunk when speech ends startTime: 12360 // Time when speech started duration: 2160 // Duration of current speech block
Event codes
Event codes are passed to the processAudio
promises.
VAD.Event.ERROR
Constant for voice detection errors.
VAD.Event.SILENCE
Constant for voice detection results with no detected voices.
VAD.Event.VOICE
Constant for voice detection results with detected voice.
VAD.Event.NOISE
Constant for voice detection results with detected noise. Not implemented yet
Available VAD Modes
These contants can be used as the mode
parameter of the VAD
constructor to
configure the VAD algorithm.
VAD.Mode.NORMAL
Constant for normal voice detection mode. Suitable for high bitrate, low-noise data.
May classify noise as voice, too. The default value if mode
is omitted in the constructor.
VAD.Mode.LOW_BITRATE
Detection mode optimised for low-bitrate audio.
VAD.Mode.AGGRESSIVE
Detection mode best suited for somewhat noisy, lower quality audio.
VAD.Mode.VERY_AGGRESSIVE
Detection mode with lowest miss-rate. Works well for most inputs.
Notes
The library is designed to work with input streams in mind, that is, sample buffers fed to processAudio
should be
rather short (36ms to 144ms - depending on your needs) and the sample rate no higher than 32kHz. Sample rates higher than
than 16kHz provide no benefit to the VAD algorithm, as human voice patterns center around 4000 to 6000Hz. Minding the
Nyquist-frequency yields sample rates between 8000 and 12000Hz for best results.
Example
See examples folder for a working examples with a sample audio file.
Non-stream example:
const vad = VADModeNORMAL; const stream = fs;stream;
Stream example:
const inputStream = fs;const vadStream = VAD; inputStream;