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(someEncodedAudio, someEncodedAudio.Length, decoded, samplesPerFrame, false);

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();