Picovoice 2.1.0

Picovoice SDK for .NET

Picovoice

Made in Vancouver, Canada by Picovoice

Picovoice is an end-to-end platform for building voice products on your terms. It enables creating voice experiences similar to Alexa and Google. But it entirely runs 100% on-device. Picovoice is

• Private: Everything is processed offline. Intrinsically HIPAA and GDPR-compliant.
• Reliable: Runs without needing constant connectivity.
• Zero Latency: Edge-first architecture eliminates unpredictable network delay.
• Accurate: Resilient to noise and reverberation. It outperforms cloud-based alternatives by wide margins *.
• Cross-Platform: Design once, deploy anywhere. Build using familiar languages and frameworks.

Requirements

• .NET Core 3.1

Compatibility

Platform compatible with .NET Framework 4.6.1+:

• Windows (x86_64)

Platforms compatible with .NET Core 2.0+:

• Linux (x86_64)
• macOS (x86_64)
• Windows (x86_64)

Platforms compatible with .NET Core 3.1+:

• Raspberry Pi:
  • 2
  • 3 (32 and 64 bit)
  • 4 (32 and 64 bit)
• NVIDIA Jetson Nano
• BeagleBone

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

AccessKey

Picovoice requires a valid AccessKey at initialization. AccessKeys act as your credentials when using Picovoice SDKs. You can create your AccessKey for free. Make sure to keep your AccessKey secret.

To obtain your AccessKey:

1. Login or Signup for a free account on the Picovoice Console.
2. Once logged in, go to the AccessKey tab to create one or use an existing AccessKey.

Usage

Create an instance of the engine

using Pv;

const string accessKey = "${ACCESS_KEY}"; // obtained from Picovoice Console (https://console.picovoice.ai/)

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 = Picovoice.Create(accessKey,
                                 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. accessKey is your Picovoice AccessKey. 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 = Picovoice.Create(accessKey, keywordPath, wakeWordCallback, contextPath, inferenceCallback))
{
    // .. Picovoice usage here
}

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.

Demos

The Picovoice dotnet demo is a .NET Core command line application that allows for processing real-time audio (i.e. microphone) and files using Picovoice.