Question

我已经完成了基础知识。但是，输出文件只是一遍又一遍地重复WAV标题。生成的文件大小合适，但它是垃圾文件。

我正在尝试使用扩展AudioInputStream的类，这样我就可以将它与其他代码无缝地结合使用，这些代码会将它与另一个AudioInputStream混合使用（它可以很好地工作）。

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.UnsupportedAudioFileException;

public class TrimmerAIS extends AudioInputStream{

private final AudioInputStream stream;
private final long startByte,endByte;
private long t_bytesRead=0;
public TrimmerAIS(AudioFormat audioFormat,AudioInputStream audioInputStream,long startMilli,long endMilli){
    super(new ByteArrayInputStream(new byte[0]),audioFormat,AudioSystem.NOT_SPECIFIED);
    stream=audioInputStream;
    //startByte=(long)((startMilli/1000f)*stream.getFormat().getSampleRate()*stream.getFormat().getSampleSizeInBits()*stream.getFormat().getChannels())/8;
    //endByte=(long)((endMilli/1000f)*stream.getFormat().getSampleRate()*stream.getFormat().getSampleSizeInBits()*stream.getFormat().getChannels())/8;
    startByte=(long)((startMilli/1000)*stream.getFormat().getFrameRate()*stream.getFormat().getFrameSize());
    endByte=(long)((endMilli/1000)*stream.getFormat().getFrameRate()*stream.getFormat().getFrameSize());
}
private byte[] tempBuffer;

@Override
public int available() throws IOException{
    return (int)(endByte-startByte-t_bytesRead);
}
public int read(byte[] abData,int nOffset,int nLength) throws IOException{
    // set up the temporary byte buffer
    if(tempBuffer==null||tempBuffer.length<nLength){
        tempBuffer=new byte[nLength];
    }
    int bytesRead=0;
    if(t_bytesRead<startByte){
        do{//skip to starting byte
            bytesRead=(int)skip(startByte-t_bytesRead);
            t_bytesRead+=bytesRead;
        }while(t_bytesRead<startByte);
    }
    if(t_bytesRead>=endByte){
        return -1;
    }

    bytesRead=stream.read(tempBuffer,0,nLength);
    if(bytesRead==-1){//premature EOF
        return -1;
    }else if(bytesRead==0){
        return 0;
    }
    t_bytesRead+=bytesRead;
    if(t_bytesRead>=endByte){//correct bytes read to exclude any bytes over the limit
        bytesRead=(int)(bytesRead-(t_bytesRead-endByte));
    }
    return bytesRead;
}
public static void main(String[] args) throws UnsupportedAudioFileException, IOException{
    AudioInputStream music=null;
    music = AudioSystem.getAudioInputStream(new File("music/0.wav"));
    music=new TrimmerAIS(music.getFormat(),music,0,15000);
    AudioSystem.write(music,AudioFileFormat.Type.WAVE,new File("out.wav"));
}
}

我根本找不到任何错误。我确实在这里找到了与https://forums.oracle.com/forums/thread.jspa?threadID=2136229&tstart=0相关联的类似帖子。除了你给它的开始和结束位置（以毫秒为单位）之外，这是我的做法，它可以传递给/包裹在另一个AIS或输出中，而无需将所需的段读入数组然后再写入。在过去的3个小时里一直试图弄清楚这一点，我的想法有点油腻。因此，如果某些事情没有意义，请随意要求澄清。我宁愿不解析文件，但如果我必须这样做。

Answer 1

嘿，哎呀！只需要删除tempBuffer并用abData替换它。是漫长的一天。以下是更正后的代码。考虑删除这个，因为这是一个简单的错误，但我创建这个类的唯一原因是因为它还不存在。

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;

import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.UnsupportedAudioFileException;

public class TrimmerAIS extends AudioInputStream{

private final AudioInputStream stream;
private final long startByte,endByte;
private long t_bytesRead=0;

public TrimmerAIS(AudioFormat audioFormat,AudioInputStream audioInputStream,long startMilli,long endMilli){
    super(new ByteArrayInputStream(new byte[0]),audioFormat,AudioSystem.NOT_SPECIFIED);
    stream=audioInputStream;
    //calculate where to start and where to end
    startByte=(long)((startMilli/1000)*stream.getFormat().getFrameRate()*stream.getFormat().getFrameSize());
    endByte=(long)((endMilli/1000)*stream.getFormat().getFrameRate()*stream.getFormat().getFrameSize());
}

@Override
public int available() throws IOException{
    return (int)(endByte-startByte-t_bytesRead);
}
public int read(byte[] abData,int nOffset,int nLength) throws IOException{
    int bytesRead=0;
    if(t_bytesRead<startByte){
        do{
            bytesRead=(int)skip(startByte-t_bytesRead);
            t_bytesRead+=bytesRead;
        }while(t_bytesRead<startByte);
    }
    if(t_bytesRead>=endByte)//end reached. signal EOF
        return -1;

    bytesRead=stream.read(abData,0,nLength);
    if(bytesRead==-1)
        return -1;
    else if(bytesRead==0)
        return 0;

    t_bytesRead+=bytesRead;
    if(t_bytesRead>=endByte)// "trim" the extra by altering the number of bytes read
        bytesRead=(int)(bytesRead-(t_bytesRead-endByte));

    return bytesRead;
}
public static void main(String[] args) throws UnsupportedAudioFileException, IOException{
    AudioInputStream music=null;
    music = AudioSystem.getAudioInputStream(new File("music/0.wav"));
    music=new TrimmerAIS(music.getFormat(),music,0,15000);
    AudioSystem.write(music,AudioFileFormat.Type.WAVE,new File("out.wav"));
}
}

Answer 2

我不完全确定，但似乎您还需要为read（）函数添加覆盖。我说的原因我不完全确定，因为某些IDE可能会自动运行，就好像该函数被覆盖一样。应用我的修正，看它是否有效。

使用Java声音API从WAV文件中修剪开始和结束

2 个答案: