Picovoice.Cheetah 1.0.0

Cheetah Binding for .NET

Cheetah Speech-to-Text Engine

Made in Vancouver, Canada by Picovoice

Cheetah is an on-device streaming speech-to-text engine. Cheetah is:

• Private; All voice processing runs locally.
• Accurate [1]
• Compact and Computationally-Efficient [2]
• Cross-Platform:
  • Linux (x86_64)
  • macOS (x86_64, arm64)
  • Windows (x86_64)
  • Android
  • iOS
  • Raspberry Pi (4, 3)
  • NVIDIA Jetson Nano

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:
  • 3 (32 and 64 bit)
  • 4 (32 and 64 bit)
• NVIDIA Jetson Nano

Installation

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

dotnet add package Picovoice.Cheetah

AccessKey

AccessKey is your authentication and authorization token for deploying Picovoice SDKs, including Cheetah. Anyone who is using Picovoice needs to have a valid AccessKey. You must keep your AccessKey secret. You would need internet connectivity to validate your AccessKey with Picovoice license servers even though the voice recognition is running 100% offline.

AccessKey also verifies that your usage is within the limits of your account. Everyone who signs up for Picovoice Console receives the Free Tier usage rights described here. If you wish to increase your limits, you can purchase a subscription plan.

Usage

Create an instance of the engine and transcribe an audio file:

using Pv;

const string accessKey = "${ACCESS_KEY}";

Cheetah handle = Cheetah.Create(accessKey);

Replace ${ACCESS_KEY} with yours obtained from Picovoice Console.

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;
}

string transcript = "";

while(true)
{
    CheetahTranscript transcriptObj = handle.Process(GetNextAudioFrame());   
    transcript += transcriptObj.Transcript;

    if (transcriptObj.IsEndpoint) {
        CheetahTranscript finalTranscriptObj = handle.Flush();
        transcript += finalTranscriptObj.Transcript;
    }
}

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

using(Cheetah handle = Cheetah.Create(accessKey))
{
    // .. Cheetah usage here
}

The model file contains the parameters for the Cheetah engine. You may create bespoke language models using Picovoice Console and then pass in the relevant file.

using Pv;

const string accessKey = "${ACCESS_KEY}";
string modelPath = "/absolute/path/to/model.pv";

Cheetah handle = Cheetah.Create(accessKey, modelPath);

Demos

The Cheetah dotnet demo project is a .NET Core console app that allows for processing real-time audio (i.e. microphone) and files using Cheetah.