PvSpeaker

PvSpeaker Binding for .NET

PvSpeaker

PvSpeaker is an easy-to-use, cross-platform audio player designed for real-time speech audio processing. It allows developers to send raw PCM frames to an audio device's output stream.

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)

• Windows (arm64)

• macOS (arm64)

Installation

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

dotnet add package PvSpeaker

Usage

Initialize and start PvSpeaker:

using Pv;

var speaker = new PvSpeaker(
    sampleRate: 22050,
    bitsPerSample: 16);

speaker.Start();

Write PCM data to the speaker:

public static byte[] GetNextAudioFrame() { }

int writtenLength = speaker.Write(GetNextAudioFrame());

Note: the Write() method only writes as much PCM data as the internal circular buffer can currently fit, and returns the number of samples that were successfully written.

When all frames have been written, run Flush() to wait for all buffered PCM data (i.e. previously buffered via Write()) to be played:

int flushedLength = speaker.Flush();

Note: calling Flush() with PCM data as an argument will both write that PCM data and wait for all buffered PCM data to finish.

public static byte[] GetRemainingAudioFrames() { }

int flushedLength = speaker.Flush(GetRemainingAudioFrames());

To stop the audio output device, run Stop():

speaker.Stop();

Once you are done, free the resources acquired by PvSpeaker. You do not have to call Stop() before Dispose():

speaker.Dispose();

To have resources freed immediately after use without explicitly calling the Dispose() function, wrap PvSpeaker in a using statement:

using (var speaker = new PvSpeaker(sampleRate: 22050, bitsPerSample: 16)) {
    // PvSpeaker usage
}

Selecting an Audio Device

To print a list of available audio devices:

string[] devices = PvSpeaker.GetAudioDevices();

The index of the device in the returned list can be used in Create() to select that device for audio playback:

var speaker = new PvSpeaker(
    sampleRate: 22050,
    bitsPerSample: 16,
    deviceIndex: 2);

Demo

The PvSpeaker .NET demo is a .NET command-line application that demonstrates how to use PvSpeaker to play audio from a WAV file.