OpusSharp

OpusSharp aims to be a cross platform, pure and ported C# compatible version of the native opus codec/library. The core library uses the native compiled DLL's/binaries. Currently, Windows, Android and Linux binaries are available. iOS and MacOS are in the works. OpusSharp compiles the opus binaries using a github actions file which is available here.

Note

While OpusSharp.Core contains minimal pre-made decoder and encoder handlers, you can create your own as all the SafeHandlers and NativeOpus functions are exposed and fully documented. However to get a minimal setup working, check the example below.

Encoder Example

using OpusSharp.Core;

byte[] someAudioData = ...;
var frameSizeMs = 20;
var sampleRate = 48000;
var channels = 1;
var samplesPerFrame = sampleRate / (1000 / frameSizeMs) * channels; //960 samples per frame.
var encoder = new OpusEncoder(sampleRate, channels, OpusPredefinedValues.OPUS_APPLICATION_VOIP);

byte[] encodedAudio = new byte[1000] //1000 bytes for an encoded buffer should be enough according to the opus documentation.
var encodedBytes = encoder.Encode(someAudioData, samplesPerFrame, encodedAudio, encodedAudio.Length);

//We can use encodedBytes to trim any excess data from the encodedAudio buffer before sending over the network or writing to a file.

Decoder Example

using OpusSharp.Core;

byte[] someEncodedAudio = ...;
var frameSizeMs = 20;
var sampleRate = 48000;
var channels = 1;
var samplesPerFrame = sampleRate / (1000 / frameSizeMs) * channels; //960 samples per frame.
var decoder = new OpusDecoder(sampleRate, channels);

var decoded = new byte[1920]; //We get 1920 bytes from doing this calculation because 16/8 (16 bit audio, 1 byte is 8 bits) equals 2 multiplied by samplesPerFrame gets us bytes per frame. 16/(sizeof(byte) * 8) * samplesPerFrame
var decodedSamples = decoder.Decode(encoded, someEncodedAudio.Length, decoded, 960, false); //Still don't know why opus only returns decoded samples but it does...

Basic NAudio Example

using NAudio.Wave;
using OpusSharp.Core;

var format = new WaveFormat(48000, 2);
var buffer = new BufferedWaveProvider(format) { ReadFully = true };
var encoder = new OpusEncoder(format.SampleRate, format.Channels, OpusPredefinedValues.OPUS_APPLICATION_VOIP);
var decoder = new OpusDecoder(format.SampleRate, format.Channels);
var recorder = new WaveInEvent() { BufferMilliseconds = 20, WaveFormat = format };
var player = new WaveOutEvent();
recorder.DataAvailable += Recorder_DataAvailable;

recorder.StartRecording();
player.Init(buffer);
player.Play();

void Recorder_DataAvailable(object? sender, WaveInEventArgs e)
{
    var encoded = new byte[1000];
    var encodedBytes = encoder.Encode(e.Buffer, 960, encoded, encoded.Length);
    Console.WriteLine(encodedBytes);
    var decoded = new byte[3840];
    var decodedSamples = decoder.Decode(encoded, encodedBytes, decoded, 960, false);
    Console.WriteLine(decodedSamples);
    buffer.AddSamples(decoded, 0, decoded.Length);
}

Console.ReadLine();

CTL Example using OpusSharp.Core.Extensions

using OpusSharp.Core;
using OpusSharp.Core.Extensions;

OpusEncoder encoder = new OpusEncoder(48000, 2, OpusPredefinedValues.OPUS_APPLICATION_AUDIO);

encoder.SetComplexity(2);
Console.WriteLine(encoder.GetComplexity());

CTL Example

using OpusSharp.Core;

OpusEncoder encoder = new OpusEncoder(48000, 2, OpusPredefinedValues.OPUS_APPLICATION_VOIP);

//1 == true, 0 == false
encoder.Ctl<int>(EncoderCTL.OPUS_SET_VBR, 1); //OpusSharp already checks if an error occurred with the CTL request and will throw an OpusException if there is an error, otherwise OpusErrorCodes.OPUS_OK.

//Most setter CTL's do not require a pointer reference. All Getter CTL's require a pointer reference (for now).

Note

While disposing of encoder's and decoder's are handled by the GC (garbage collector) since unmanaged states are wrapped in a SafeHandler, It is still recommended to directly call the Dispose() function due to different runtime environments such as unity's mono runtime (at the time of writing this) which can take an impact on performance depending on how many is initialized and dereferenced over time.

Supported Devices

• ✅ Fully and natively supported.
• ❎ Can be supported but no reason to.
• ❗ Not yet available.
• ❌ Not planned, Not supported.

Device	x64	x86	arm32	arm64
Linux	✅	✅	✅	✅
Android	✅	✅	✅	✅
Windows	✅	✅	✅	✅
iOS	❗	❗	❗	❗
MacOS	❗	❗	❗	❗

Installation

Please check QuickStart OR Nuget

API Documentation

https://avionblock.github.io/OpusSharp/api/OpusSharp.Core.html

Opus License

https://opus-codec.org/license/