Picovoice Platform — .NET API

This document outlines how to integrate Picovoice platform within an application using its .NET API.

Requirements

• .NET SDK 3.1+

Compatibility

• .NET Standard 2.0, .NET Core 2.0+ and .NET Framework 4.6.1+
• Runs on Linux (x86_64), macOS (x86_64) and Windows (x86_64)

Installation

You can install the latest version of Picovoice by adding the latest Picovoice NuGet package in Visual Studio or using the .NET CLI.

dotnet add package Picovoice

Usage

Create an instance of the engine

using Pv;
 
string keywordPath = "/absolute/path/to/keyword.ppn";
 
void wakeWordCallback() => {..}
 
string contextPath = "/absolute/path/to/context.rhn";
 
void inferenceCallback(Inference inference)
{
    // `inference` exposes three immutable properties:
    // (1) `IsUnderstood`
    // (2) `Intent`
    // (3) `Slots`
    // ..
}
 
Picovoice handle = new Picovoice(keywordPath,
                                 wakeWordCallback,
                                 contextPath,
                                 inferenceCallback);

handle is an instance of Picovoice runtime engine that detects utterances of wake phrase defined in the file located at keywordPath. Upon detection of wake word it starts inferring user's intent from the follow-on voice command within the context defined by the file located at contextPath. keywordPath is the absolute path to Porcupine wake word engine keyword file (with .ppn suffix). contextPath is the absolute path to Rhino Speech-to-Intent engine context file (with .rhn suffix). wakeWordCallback is invoked upon the detection of wake phrase and inferenceCallback is invoked upon completion of follow-on voice command inference.

When instantiated, valid sample rate can be obtained via handle.SampleRate. Expected number of audio samples per frame is handle.FrameLength. The engine accepts 16-bit linearly-encoded PCM and operates on single-channel audio.

short[] GetNextAudioFrame()
{
    // .. get audioFrame
    return audioFrame;
}
 
while(true)
{
    handle.Process(GetNextAudioFrame());
}

Picovoice will have its resources freed by the garbage collector, but to have resources freed immediately after use, wrap it in a using statement:

using(Picovoice handle = new Picovoice(keywordPath, wakeWordCallback, contextPath, inferenceCallback))
{
    // .. Picovoice usage here
}

Custom Wake Word & Context

You can create custom Porcupine wake word and Rhino context models using Picovoice Console

Non-English Models

In order to detect wake words and run inference in other languages you need to use the corresponding model file. The model files for all supported languages are available here and here.