java 使用 jtransforms 库 实现将指定 wav 音频文件拆分成不同频段的音频文件

引入 maven 依赖:


    net.sourceforge.jtransforms
    jtransforms
    2.4.0

测试类 FourierTransformTest.java:

import edu.emory.mathcs.jtransforms.fft.DoubleFFT_1D;

import javax.sound.sampled.UnsupportedAudioFileException;
import java.io.File;
import java.io.IOException;

public class FourierTransformTest {
    public static void main(String[] args) throws UnsupportedAudioFileException, IOException {
        // 假设有一个音频的采样数据,存储在一个double数组中
        File srcWavFile = new File("C:\\E\\素材\\音频\\wav\\audio.wav");
        double[] audioData = AudioUtils.wavToDoubleArray( srcWavFile );
        System.out.println( "audioData.length = " + audioData.length );

        // 对音频数据进行傅里叶变换
        new DoubleFFT_1D(audioData.length).realForward(audioData);

        /*
        经过傅里叶变换后生成的double[]中的每个元素表示频谱图中对应频率的幅度。
            傅里叶变换将时域信号转换为频域信号,将波形图转换为频谱图。
            在频谱图中,横轴表示频率,纵轴表示幅度。double[]中的每个元素对应频谱图中的一个频率,其数值表示该频率对应的幅度大小。
            通过分析这些幅度值,可以了解波形图中不同频率成分的强弱程度。
         */

        // 将傅里叶变换后的频谱数据分成三个频段
        int segmentSize = audioData.length / 3;

        double[] audio1 = new double[segmentSize];
        double[] audio2 = new double[segmentSize];
        double[] audio3 = new double[segmentSize];

        System.arraycopy(audioData, segmentSize * 0, audio1, 0, segmentSize);
        System.arraycopy(audioData, segmentSize * 1, audio2, 0, segmentSize);
        System.arraycopy(audioData, segmentSize * 2, audio3, 0, segmentSize);

        // 对分离出的音频数据进行逆傅里叶变换,得到分离后的音频
        new DoubleFFT_1D( audio1.length ).realInverse( audio1, true );
        new DoubleFFT_1D( audio2.length ).realInverse( audio2, true );
        new DoubleFFT_1D( audio3.length ).realInverse( audio3, true );
        System.out.println("转换完毕");

        // 分离后的音频数据存储在audio1、audio2和audio3数组中,可将其转换成 wav文件
        AudioUtils.doubleArrayToWAV( audio1,new File( "C:\\E\\素材\\音频\\wav\\part1.wav" ) );
        AudioUtils.doubleArrayToWAV( audio2,new File( "C:\\E\\素材\\音频\\wav\\part2.wav" ) );
        AudioUtils.doubleArrayToWAV( audio3,new File( "C:\\E\\素材\\音频\\wav\\part3.wav" ) );
        System.out.println("生成完毕");
    }
}

用到的工具类 AudioUtils.java:

import javax.sound.sampled.*;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;

public class AudioUtils {

    public static double[] wavToDoubleArray(File mp3File) throws UnsupportedAudioFileException, IOException {
        AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(mp3File);
        AudioFormat audioFormat = audioInputStream.getFormat();
        int numChannels = audioFormat.getChannels();
        int sampleSizeInBytes = audioFormat.getSampleSizeInBits() / 8;
        int frameSize = numChannels * sampleSizeInBytes;
        int bufferSize = (int) (audioInputStream.getFrameLength() * frameSize);
        byte[] audioBytes = new byte[bufferSize];
        audioInputStream.read(audioBytes);

        double[] audioData = new double[audioBytes.length / 2];
        for (int i = 0, j = 0; i < audioBytes.length; i += 2, j++) {
            int sample = (audioBytes[i + 1] << 8) | (audioBytes[i] & 0xFF);
            audioData[j] = sample / 32768.0;
        }

        return audioData;
    }

    public static void doubleArrayToWAV(double[] audioData, File outputFile) throws IOException, UnsupportedAudioFileException {
        AudioFormat audioFormat = new AudioFormat(44100, 16, 2, true, false);
        byte[] audioBytes = new byte[audioData.length * 2];
        for (int i = 0, j = 0; i < audioData.length; i++, j += 2) {
            short sample = (short) (audioData[i] * 32767);
            audioBytes[j] = (byte) (sample & 0xFF);
            audioBytes[j + 1] = (byte) ((sample >> 8) & 0xFF);
        }

        AudioInputStream audioInputStream = new AudioInputStream(new ByteArrayInputStream(audioBytes), audioFormat, audioData.length);
        AudioSystem.write(audioInputStream, AudioFileFormat.Type.WAVE, outputFile);
    }
}

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