java - 如何使用 FFT 从 PCM 获取频率数据

Question

我有一组音频数据要传递给读者:

 recorder.read(audioData,0,bufferSize); 

实例化如下:

AudioRecord recorder;
short[] audioData;
int bufferSize;
int samplerate = 8000;

//get the buffer size to use with this audio record
bufferSize = AudioRecord.getMinBufferSize(samplerate, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT)*3;

//instantiate the AudioRecorder
recorder = new AudioRecord(AudioSource.MIC,samplerate, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT,bufferSize); 

recording = true; //variable to use start or stop recording
audioData = new short [bufferSize]; //short array that pcm data is put into.

我有一个在网上找到的 FFT 类(class)和一个复杂的类(class)。我试了两天在网上到处找，但无法弄清楚如何遍历 audioData 中存储的值并将其传递给 FFT。

这是我正在使用的 FFT 类:http://www.cs.princeton.edu/introcs/97data/FFT.java这是一个复杂的类:http://introcs.cs.princeton.edu/java/97data/Complex.java.html

Answer 1

假设 audioData 数组包含原始音频数据，您需要从 audioData 数组创建一个 Complex[] 对象，如下所示:

Complex[] complexData = new Complex[audioData.length];
for (int i = 0; i < complexData.length; i++) {
    complextData[i] = new Complex(audioData[i], 0);
}

现在您可以将 complexData 对象作为参数传递给 FFT 函数:

Complex[] fftResult = FFT.fft(complexData);