一文教你从0到1搭建C#音频分析平台

# 使用nuget安装以下库
install-package naudio        # 音频输入/输出/处理
install-package livecharts    # 实时波形/频谱可视化
install-package ffmpeg.autogen # 音频格式转换（可选）

// 项目目录建议
/assets              // 图片/资源文件
/controllers         // 音频控制逻辑
/models              // 数据模型（如波形数据、频谱数据）
/views               // 窗体/界面
/utilities           // 工具类（如fft计算、文件io）

using naudio.wave;

public class audioinputmanager : idisposable {
    private waveinevent _wavein;
    private wavefilewriter _writer;
    private bool _isrecording = false;

    // 构造函数：初始化音频设备
    public audioinputmanager(int deviceid = 0, int samplerate = 44100, int channels = 1) {
        _wavein = new waveinevent {
            devicenumber = deviceid,
            waveformat = new waveformat(samplerate, channels)
        };
        _wavein.dataavailable += ondataavailable;
    }

    // 开始录音
    public void startrecording(string outputfilepath) {
        _isrecording = true;
        _writer = new wavefilewriter(outputfilepath, _wavein.waveformat);
        _wavein.startrecording();
        console.writeline("音频录制已启动");
    }

    // 停止录音
    public void stoprecording() {
        _isrecording = false;
        _wavein.stoprecording();
        _writer.dispose();
        console.writeline("音频录制已停止");
    }

    // 处理音频数据
    private void ondataavailable(object sender, waveineventargs e) {
        if (_isrecording) {
            _writer.write(e.buffer, 0, e.bytesrecorded); // 写入文件
            processaudiodata(e.buffer, e.bytesrecorded); // 实时分析
        }
    }

    // 实时分析音频数据（波形/频谱）
    private void processaudiodata(byte[] buffer, int bytesread) {
        // 将字节转换为短整型（16位pcm）
        short[] samples = new short[bytesread / 2];
        buffer.blockcopy(buffer, 0, samples, 0, bytesread);

        // 提取波形数据（用于livecharts）
        models.waveformmodel.instance.addsamples(samples);

        // 计算频谱（fft）
        double[] spectrum = fft.calculatefft(samples, _wavein.waveformat.samplerate);
        models.spectrummodel.instance.updatespectrum(spectrum);
    }

    // 释放资源
    public void dispose() {
        _wavein.dispose();
        _writer?.dispose();
    }
}

public class waveformmodel {
    public static waveformmodel instance { get; } = new waveformmodel();
    private list<double> _samples = new list<double>();

    public void addsamples(short[] samples) {
        foreach (var sample in samples) {
            _samples.add(sample / 32768.0); // 归一化到[-1,1]
            if (_samples.count > 4096) _samples.removeat(0); // 限制最大样本数
        }
    }

    public list<double> getsamples() => _samples;
}

public static class fft {
    public static double[] calculatefft(short[] samples, int samplerate) {
        int n = samples.length;
        complex[] data = new complex[n];

        // 将短整型转换为complex类型
        for (int i = 0; i < n; i++) {
            data[i] = new complex(samples[i], 0);
        }

        // 执行快速傅里叶变换（fft）
        fourier.forwardfouriertransform(data, fourieroptions.noscaling);

        // 计算幅度谱（只取前半部分）
        double[] magnitude = new double[n / 2];
        for (int i = 0; i < n / 2; i++) {
            magnitude[i] = math.sqrt(data[i].x * data[i].x + data[i].y * data[i].y);
        }

        // 转换为分贝（db）刻度
        for (int i = 0; i < magnitude.length; i++) {
            if (magnitude[i] > 0) {
                magnitude[i] = 20 * math.log10(magnitude[i] / (n / 2));
            } else {
                magnitude[i] = -100; // 避免除以0
            }
        }

        return magnitude;
    }
}

using livecharts;
using livecharts.wpf;

public class waveformchart : chart {
    public waveformchart() {
        series = new seriescollection {
            new lineseries {
                title = "waveform",
                values = new chartvalues<double>(),
                linesmooth = false,
                pointgeometry = null
            }
        };

        // 自动更新数据
        this.datacontext = models.waveformmodel.instance;
        this.bindingcontext = new binding("getsamples") {
            mode = bindingmode.oneway
        };
    }
}

public class spectrumchart : chart {
    public spectrumchart() {
        series = new seriescollection {
            new columnseries {
                title = "spectrum",
                values = new chartvalues<double>(),
                datalabels = false
            }
        };

        // 自动更新数据
        this.datacontext = models.spectrummodel.instance;
        this.bindingcontext = new binding("getspectrum") {
            mode = bindingmode.oneway
        };
    }
}

public class audiofeatures {
    public static double calculaterms(short[] samples) {
        double sum = 0;
        foreach (var sample in samples) {
            sum += sample * sample;
        }
        return math.sqrt(sum / samples.length) / 32768.0; // 归一化到[0,1]
    }

    public static double calculatezerocrossingrate(short[] samples) {
        int count = 0;
        for (int i = 1; i < samples.length; i++) {
            if ((samples[i - 1] >= 0 && samples[i] < 0) || 
                (samples[i - 1] < 0 && samples[i] >= 0)) {
                count++;
            }
        }
        return count / (double)samples.length;
    }

    public static double calculatespectralcentroid(double[] spectrum, int samplerate) {
        double sum = 0, total = 0;
        for (int i = 0; i < spectrum.length; i++) {
            double freq = i * (samplerate / 2.0) / spectrum.length;
            sum += freq * spectrum[i];
            total += spectrum[i];
        }
        return total == 0 ? 0 : sum / total;
    }
}

public partial class mainform : form {
    private audioinputmanager _audiomanager;

    public mainform() {
        initializecomponent();

        // 初始化音频管理器
        _audiomanager = new audioinputmanager();

        // 绑定可视化组件
        waveformchart.datasource = models.waveformmodel.instance.getsamples();
        spectrumchart.datasource = models.spectrummodel.instance.getspectrum();
    }

    private void btnstart_click(object sender, eventargs e) {
        _audiomanager.startrecording("output.wav");
        btnstart.enabled = false;
        btnstop.enabled = true;
    }

    private void btnstop_click(object sender, eventargs e) {
        _audiomanager.stoprecording();
        btnstop.enabled = false;
        btnstart.enabled = true;
    }

    protected override void onformclosing(formclosingeventargs e) {
        _audiomanager.dispose();
        base.onformclosing(e);
    }
}