c# - 带有NAudio和WPFSoundVisualizationLib的频谱分析仪

我正在使用C#4.0/WPF实时频谱分析仪(作为另一个项目的基础)。我使用NAudio的最新版本在声卡上获取实时音频输出，并使用WPFSoundVisualizationLib(http://wpfsvl.codeplex.com/)进行频谱分析仪WPF控件。有了这个惊人的工具，这项工作几乎完成了，但是却无法正常工作:-(

我有一个功能齐全的Spectrum，但信息无权，而且我不明白问题的出处...(我将我的Spectrum与Equalify(Spotify的Spectrum/均衡器)进行了比较，但我没有相同的结果行为)

这是我的主要类(class):

using System;
using System.Windows;
using WPFSoundVisualizationLib;

namespace MySpectrumAnalyser
{
    public partial class MainWindow : Window
    {
        private RealTimePlayback _playback;
        private bool _record;

        public MainWindow()
        {
            InitializeComponent();
            this.Topmost = true;
            this.Closing += MainWindow_Closing;
            this.spectrum.FFTComplexity = FFTDataSize.FFT2048;
            this.spectrum.RefreshInterval = 60;
        }

        private void MainWindow_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            if (this._record)
            {
                this._playback.Stop();
            }
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            if (this._playback == null)
            {
                this._playback = new RealTimePlayback();
                this.spectrum.RegisterSoundPlayer(this._playback);
            }

            if (!this._record)
            {
                this._playback.Start();
                this.Dispatcher.Invoke(new Action(delegate
                {
                    this.btnRecord.Content = "Stop";
                }));
            }
            else
            {
                this._playback.Stop();
                this.Dispatcher.Invoke(new Action(delegate
                {
                    this.btnRecord.Content = "Start";
                }));
            }

            this._record = !this._record;
        }
    }
}

还有我的回送分析器(实现ISpectrumPlayer与WPFSoundVisualizationLib Spectrum控件一起使用)。

LoopbackCapture继承NAudio.CoreAudioApi.WasapiCapture。

从Wasapi接收的数据是一个字节数组(32位PCM，44.1kHz，2个 channel ，每个样本32位)

using NAudio.Dsp;
using NAudio.Wave;
using System;
using WPFSoundVisualizationLib;

namespace MySpectrumAnalyser
{
    public class RealTimePlayback : ISpectrumPlayer
    {
        private LoopbackCapture _capture;
        private object _lock;
        private int _fftPos;
        private int _fftLength;
        private Complex[] _fftBuffer;
        private float[] _lastFftBuffer;
        private bool _fftBufferAvailable;
        private int _m;

        public RealTimePlayback()
        {
            this._lock = new object();

            this._capture = new LoopbackCapture();
            this._capture.DataAvailable += this.DataAvailable;

            this._m = (int)Math.Log(this._fftLength, 2.0);
            this._fftLength = 2048; // 44.1kHz.
            this._fftBuffer = new Complex[this._fftLength];
            this._lastFftBuffer = new float[this._fftLength];
        }

        public WaveFormat Format
        {
            get
            {
                return this._capture.WaveFormat;
            }
        }

        private float[] ConvertByteToFloat(byte[] array, int length)
        {
            int samplesNeeded = length / 4;
            float[] floatArr = new float[samplesNeeded];

            for (int i = 0; i < samplesNeeded; i++)
            {
                floatArr[i] = BitConverter.ToSingle(array, i * 4);
            }

            return floatArr;
        }

        private void DataAvailable(object sender, WaveInEventArgs e)
        {
            // Convert byte[] to float[].
            float[] data = ConvertByteToFloat(e.Buffer, e.BytesRecorded);

            // For all data. Skip right channel on stereo (i += this.Format.Channels).
            for (int i = 0; i < data.Length; i += this.Format.Channels)
            {
                this._fftBuffer[_fftPos].X = (float)(data[i] * FastFourierTransform.HannWindow(_fftPos, _fftLength));
                this._fftBuffer[_fftPos].Y = 0;
                this._fftPos++;

                if (this._fftPos >= this._fftLength)
                {
                    this._fftPos = 0;

                    // NAudio FFT implementation.
                    FastFourierTransform.FFT(true, this._m, this._fftBuffer);

                    // Copy to buffer.
                    lock (this._lock)
                    {
                        for (int c = 0; c < this._fftLength; c++)
                        {
                            this._lastFftBuffer[c] = this._fftBuffer[c].X;
                        }

                        this._fftBufferAvailable = true;
                    }
                }
            }
        }

        public void Start()
        {
            this._capture.StartRecording();
        }

        public void Stop()
        {
            this._capture.StopRecording();
        }

        public bool GetFFTData(float[] fftDataBuffer)
        {
            lock (this._lock)
            {
                // Use last available buffer.
                if (this._fftBufferAvailable)
                {
                    this._lastFftBuffer.CopyTo(fftDataBuffer, 0);
                    this._fftBufferAvailable = false;
                    return true;
                }
                else
                {
                    return false;
                }
            }
        }

        public int GetFFTFrequencyIndex(int frequency)
        {
            int index = (int)(frequency / (this.Format.SampleRate / this._fftLength / this.Format.Channels));
            return index;
        }

        public bool IsPlaying
        {
            get { return true; }
        }

        public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
    }
}

WPF控件每60毫秒调用一次GetFFTData，以更新Spectrum。

最佳答案

我可能回答这个问题有点晚了，但是我们来了。

你快到了。您只需要提供FFT返回的复数的幅度而不是X值即可。

因此，在for循环中，请执行以下操作:

this._lastFftBuffer[c] = this._fftBuffer[c].X;

做这个:

float amplitude = (float)Math.Sqrt(this._fftBuffer[c].X * this._fftBuffer[c].X + this._fftBuffer[c].Y * this._fftBuffer[c].Y);
this._lastFftBuffer[c] = amplitude;

干杯!

关于c# - 带有NAudio和WPFSoundVisualizationLib的频谱分析仪，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13398802/