Cobra 2.0.1

Cobra Binding for .NET

Cobra Voice Activity Detection Engine

Made in Vancouver, Canada by Picovoice

Cobra is an on-device streaming voice activity detection engine. Cobra is:

• Private; All voice processing runs locally.
• Accurate [1]
• Cross-Platform:
  • Linux (x86_64), macOS (x86_64, arm64), and Windows (x86_64, arm64)
  • Android and iOS
  • Chrome, Safari, Firefox, and Edge
  • Raspberry Pi (3, 4, 5)

Requirements

• .NET 8.0

Compatibility

Platform compatible with .NET Framework 4.6.1+:

• Windows (x86_64)

Platforms compatible with .NET Core 2.0+:

• macOS (x86_64)
• Windows (x86_64)

Platform compatible with .NET 6.0+:

• Raspberry Pi:

  • 3 (32 and 64 bit)
  • 4 (32 and 64 bit)
  • 5 (32 and 64 bit)

• Linux (x86_64)

• macOS (arm64)

• Windows (arm64)

Installation

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

dotnet add package Cobra

AccessKey

Cobra requires a valid Picovoice AccessKey at initialization. AccessKey acts as your credentials when using Cobra SDKs. You can get your AccessKey for free. Make sure to keep your AccessKey secret. Signup or Login to Picovoice Console to get your AccessKey.

Usage

Create an instance of the engine:

using Pv;

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

Cobra cobra = new Cobra(accessKey);

Replace ${AccessKey} with your AccessKey obtained from Picovoice Console. cobra is an instance of Cobra.

When initialized, the valid sample rate is given by cobra.SampleRate. Expected frame length (number of audio samples in an input array) is cobra.FrameLength. The engine accepts 16-bit linearly-encoded PCM and operates on single-channel audio.

Pass in frames of audio to get the probability of voice in each frame:

short[] GetNextAudioFrame()
{
    // .. get audioFrame
    return audioFrame;
}

while(true)
{
    float voiceProbability = cobra.Process(frame.ToArray());
    // .. use probability to trigger other functionality
}

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

using(Cobra cobra = new Cobra(accessKey))
{
    // .. Cobra usage here
}

Demos

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