MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using Windows.Foundation;
using Windows.Media;
using Windows.Media.Audio;
using Windows.Media.MediaProperties;
using Windows.Media.Render;
using Windows.Storage;
using Windows.UI.Xaml.Controls;

namespace App1
{
    [ComImport]
    [Guid("5B0D3235-4DBA-4D44-865E-8F1D0E4FD04D")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    unsafe interface IMemoryBufferByteAccess
    {
        void GetBuffer(out byte* buffer, out uint capacity);
    }

    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        private AudioFrameOutputNode frameOutputNode;

        private List<byte> allBytes = new List<byte>();

        public MainPage()
        {
            this.InitializeComponent();
            PrintActualBytes();
            CreateAudioGraph();
        }

        private void PrintActualBytes()
        {
            var localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
            FileStream fIn = new FileStream(localFolder.Path + @"/audio.wav", FileMode.Open);
            BinaryReader br = new BinaryReader(fIn);
            // Skip the first 44 bytes since they are header stuff
            br.ReadBytes(44);
            Debug.WriteLine("Actual bytes:");
            for (int i = 0; i < 400; i++)
            {
                if (i > 0 && i % 2 == 0) Debug.Write("| ");
                Debug.Write(br.ReadByte() + " ");
            }
            Debug.WriteLine("");
        }

        private async void CreateAudioGraph()
        {
            var encoding = MediaEncodingProfile.CreateWav(AudioEncodingQuality.Auto);
            encoding.Audio = AudioEncodingProperties.CreatePcm(16000, 1, 16);

            var settings = new AudioGraphSettings(AudioRenderCategory.Speech);
            settings.EncodingProperties = encoding.Audio;

            var result = await AudioGraph.CreateAsync(settings);
            var graph = result.Graph;

            var localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
            StorageFile file = await localFolder.GetFileAsync("audio.wav");

            var fileInputNodeResult = await graph.CreateFileInputNodeAsync(file);
            var fileInputNode = fileInputNodeResult.FileInputNode;


            fileInputNode.FileCompleted += async (AudioFileInputNode sender, object args) =>
            {
                graph.Stop();

                Debug.WriteLine("Bytes from FrameOutputNode frames:");
                // Print first 100 floats in bytes
                for (int i = 0; i < 4 * 100; i++)
                {
                    if (i > 0 && i % 4 == 0) Debug.Write("| ");
                    Debug.Write(allBytes[i] + " ");
                }
            };

            frameOutputNode = graph.CreateFrameOutputNode(encoding.Audio);

            fileInputNode.AddOutgoingConnection(frameOutputNode);
            graph.QuantumStarted += AudioGraph_QuantumStarted;

            graph.Start();
        }

        private void AudioGraph_QuantumStarted(AudioGraph sender, object args)
        {
            AudioFrame frame = frameOutputNode.GetFrame();
            ProcessFrameOutput(frame);
        }

        unsafe private void ProcessFrameOutput(AudioFrame frame)
        {
            AudioBuffer buffer = frame.LockBuffer(AudioBufferAccessMode.Read);
            IMemoryBufferReference reference = buffer.CreateReference();
            ((IMemoryBufferByteAccess)reference).GetBuffer(out byte* dataInBytes, out uint capacityInBytes);
            
            for (int i = 0; i < capacityInBytes; i++)
            {
                allBytes.Add(dataInBytes[i]);
            }
        }
    }
}