NtFreX.Audio

This .net core library provides functionality to

• read audio containers
• sample audio
• convert between audio formats
• play/record audio

Supported formats

• Wave
  • Pcm (8bps, 16bps, 32bps, 64bps)
  • Float (16bps, 32bps, 64bps)

Demo

For a demo look into the demo/NtFrex.Audio.Console project.

Samples

Read/Write an audio file

await using IAudioContainer audio = await AudioContainer.FromFileAsync("myAudio.wav")

Other methods which resolve/write an IAudioContainer are:

• AudioEnvironment.Serializer.FromDataAsync
• AudioEnvironment.Serializer.FromStreamAsync
• AudioEnvironment.Serializer.ToStreamAsync
• AudioEnvironment.Serializer.ToFileAsync
• AudioEnvironment.Serializer.ToDataAsync

There are serval extension methods which make use of those methods. If you want to build your own container you can use the WaveAudioContainerBuilder or the IntermediateAudioContainerBuilder.

Convert an audio file

await using var converted = await audio.ConvertAsync<IntermediateEnumerableAudioContainer>();

Audio sampling

await using var newAudio = await AudioEnvironment.Sampler
                                                 .SampleRateAudioSampler(WellKnownSampleRate.Hz44100)
                                                 .SampleAsync(audio, cancellationToken)

The sampler is not executed until the new audio is moved into an in memory container or written into another stream. Other samplers are available under AudioEnvironment.Sampler. Audio samplers can only be used with intermediate containers.

Other samplers are:

• BitsPerSampleAudioSampler
• SampleRateAudioSampler
• ChannelAudioSampler
• FromMonoAudioSampler
• ToMonoAudioSampler
• ShiftWaveAudioSampler
• SpeedAudioSampler
• VolumeAudioSampler
• FloatToPcmAudioSampler
• PcmToFloatAudioSampler

Audio render

await using IAudioContainer audio = await AudioContainer.FromFileAsync("myAudio.wav");
using var device = AudioDevice.GetDefaultRenderDevice();

await using var context = await device.RenderAsync(audio);

var totalLength = context.GetLength().TotalSeconds;
context.PositionChanged.Subscribe((sender, args) => LogProgress(args.Value / totalLength));

await context.EndOfPositionReached.NextEvent();

Audio capture

using var device = AudioDevice.GetDefaultCaptureDevice();

var format = device.GetDefaultFormat();
await using var sink = await FileWaveAudioSink.CreateAsync("myAudio.wav", format);

await using var context = await device.CaptureAsync(format, sink);
await Task.Delay(time);

Create a new audio file containing a sin wave

uint sampleRate = 44100; var format = new AudioFormat(sampleRate, bitsPerSample: 8, channels: 1, AudioFormatType.Pcm); var data = WaveBuilder.Sin(sampleRate, 1000, 10); await using var audio = await WaveAudioContainerBuilder .Build(data, format, isDataLittleEndian: true) .ToFileAsync(@".\audio.wav", FileMode.CreateNew);

Installation

You need to install the NtFreX.Audio nuget package and then addtional nuget packages depending on the platforms you want to use.

• For Windows 7 and upwards the NtFreX.Audio.Wasapi package

Architecture

The entry point should most of the time be the AudioEnvironment class.