实时音频处理

我想让实时音频处理与Qt和显示基频使用FFTW3。

我所做的步骤:

1. 我从计算机设备捕获任何声音并将其填充到缓冲区。
2. 我将声音样本分配给double阵列
3. 计算基频。

我的代码总是返回0作为基频。

QByteArray *buffer;
QAudioInput *audioInput;
audioInput = new QAudioInput(format, this);
//Check the number of samples in input buffer
qint64 len = audioInput->bytesReady();
//Limit sample size
if(len > 4096)
    len = 4096;
//Read sound samples from input device to buffer
qint64 l = input->read(buffer.data(), len);
if(l > 0)
{
    int input_size = BufferSize;
    // Compute corresponding number of complex output samples
    int output_size = (input_size/2 + 1);
    double *input_buffer = static_cast<double*>(fftw_malloc(input_size * sizeof(double)));
    fftw_complex *out = static_cast<fftw_complex*>(fftw_malloc(output_size * sizeof(fftw_complex)));
    //Assign sound samples to double array
    input_buffer = (double*)buffer.data();
    fftw_plan p3;
    //Create plan
    p3 = fftw_plan_dft_r2c_1d(input_size, input_buffer, out, FFTW_ESTIMATE);
    fftw_execute(p3);
    double reout[BufferSize];
    double imgout[BufferSize];
    double magnitude[BufferSize/2];
    long ffond = 0.0; // Position of the frequency
    double max = 0; // Maximal amplitude
    for (int i = 0; i < BufferSize/2; i++)
    {
        reout[i] = out[i][0];
        imgout[i] = out[i][1];
        cout << imgout[i] << endl;
        magnitude[i] = sqrt(reout[i]*reout[i] + imgout[i]*imgout[i]); //Calculate magnitude of first
        double t = sqrt(reout[i]*reout[i] + imgout[i]*imgout[i]);
        if(t > max)
        {
            max = t;
            ffond = i;
        }
    }
    qDebug() << "fundamental frequency is :" << QString::number(ffond*static_cast<double>);
    fftw_destroy_plan(p3);