Rhino - .NET API

This document outlines how to integrate Rhino Speech-to-Intent engine 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), Windows (x86_64) and Raspberry Pi (.NET Core 3.1+)

Installation

You can install the latest version of Rhino by getting the latest Rhino NuGet package in Visual Studio or using the .NET CLI:

dotnet add package Rhino

Usage

Create an instance of the engine:

using Pv;

Rhino handle = Rhino.Create(contextPath:"/absolute/path/to/context");

Where contextPath is the absolute path to a Rhino Speech-to-Intent context.

The sensitivity of the engine can be tuned using the sensitivity parameter. It is a floating point number within [0, 1]. A higher sensitivity value results in fewer misses at the cost of (potentially) increasing the erroneous inference rate.

using Pv;

Rhino handle = Rhino.Create(contextPath:"/absolute/path/to/context", sensitivity: 0.25f);

When initialized, the valid sample rate is given by handle.SampleRate. Expected frame length (number of audio samples in an input array) 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)
{
    bool isFinalized = handle.Process(GetNextAudioFrame());   
    if(isFinalized)
    {
        Inference inference = handle.GetInference();
        if(inference.IsUnderstood)
        {
            string intent = inference.Intent;
            Dictionary<string, string> slots = inference.Slots;
            // .. code to take action based on inferred intent and slot values
        }
        else
        {
            // .. code to handle unsupported commands              
        }        
    }
}

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

using(Rhino handle = Rhino.Create(contextPath:"/absolute/path/to/context"))
{
    // .. Rhino usage here
}

Custom Context

You can create custom Rhino context models using Picovoice Console.

Non-English Contexts

In order to run inference on non-English contexts you need to use the corresponding model file. The model files for all supported languages are available here.