meeting-assistant/MeetingAssistant/Recording/WindowsMicrophoneDeviceProvider.cs

using NAudio.CoreAudioApi;
using NAudio.Wave;

namespace MeetingAssistant.Recording;

public sealed class WindowsMicrophoneDeviceProvider : IMicrophoneDeviceProvider, IMicrophoneCaptureSourceFactory
{
    private readonly MicrophoneDeviceSelection selection;
    private readonly ILogger<WindowsMicrophoneDeviceProvider> logger;

    public WindowsMicrophoneDeviceProvider(
        MicrophoneDeviceSelection selection,
        ILogger<WindowsMicrophoneDeviceProvider> logger)
    {
        this.selection = selection;
        this.logger = logger;
    }

    public IReadOnlyList<MicrophoneDevice> GetAvailableMicrophones()
    {
        try
        {
            using var enumerator = new MMDeviceEnumerator();
            return enumerator
                .EnumerateAudioEndPoints(DataFlow.Capture, DeviceState.Active)
                .Select(ToMicrophoneDevice)
                .OrderBy(device => device.Name, StringComparer.CurrentCultureIgnoreCase)
                .ToArray();
        }
        catch (Exception exception)
        {
            logger.LogWarning(exception, "Could not enumerate microphone capture endpoints");
            return [];
        }
    }

    public MicrophoneDeviceSnapshot GetMicrophoneSnapshot(MeetingAssistantOptions options)
    {
        var devices = GetAvailableMicrophones();
        return new MicrophoneDeviceSnapshot(
            devices,
            selection.Resolve(options.Recording.MicrophoneDeviceId, GetDefaultMicrophone(), devices));
    }

    public IMeetingAudioSource CreateCapture(MeetingAssistantOptions options)
    {
        var current = GetMicrophoneSnapshot(options).Current;
        IWaveIn capture;
        if (current is null)
        {
            logger.LogInformation("Starting microphone capture from Windows default capture endpoint");
            capture = new WasapiCapture();
        }
        else
        {
            logger.LogInformation(
                "Starting microphone capture from {MicrophoneName} ({MicrophoneDeviceId})",
                current.Name,
                current.Id);
            using var enumerator = new MMDeviceEnumerator();
            capture = new WasapiCapture(enumerator.GetDevice(current.Id));
        }

        try
        {
            capture.WaveFormat = new WaveFormat(
                options.Recording.SampleRate,
                16,
                options.Recording.Channels);
            return new NaudioCaptureAudioSource(capture, "microphone", logger);
        }
        catch
        {
            capture.Dispose();
            throw;
        }
    }

    private static MicrophoneDevice? GetDefaultMicrophone()
    {
        try
        {
            using var enumerator = new MMDeviceEnumerator();
            return ToMicrophoneDevice(enumerator.GetDefaultAudioEndpoint(DataFlow.Capture, Role.Console));
        }
        catch
        {
            return null;
        }
    }

    private static MicrophoneDevice ToMicrophoneDevice(MMDevice device)
    {
        return new MicrophoneDevice(device.ID, device.FriendlyName);
    }
}