Write mp3 file to disk while playing in Java

Question

I have an application playing remote MP3 files over HTTP using the JLayer/BasicPlayer libraries. I want to save the played mp3 files to disk without re-downloading them.

This is the code using the JLayer based BasicPlayer for Playing the MP3 file.

String mp3Url = "http://ia600402.us.archive.org/6/items/Stockfinster.-DeadLinesutemos025/01_Push_Push.mp3";
URL url = new URL(mp3Url);
URLConnection conn = url.openConnection();
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);

BasicPlayer player = new BasicPlayer();
player.open(bis);
player.play();

How would I save the mp3 file to disk?

Joni · Accepted Answer · 2012-02-15T08:37:56.770

To avoid having to go through the bytes twice, you need to wrap the input stream from the connection in a filter that writes any data that is read to an output stream, i.e. a kind of a "tee pipe input stream." Such a class is not that difficult to write yourself, but you can save the work by using TeeInputStream from the Apache Commons IO library.

Apache Commons IO: http://commons.apache.org/io/
TeeInputStream javadoc: http://commons.apache.org/io/apidocs/org/apache/commons/io/input/TeeInputStream.html

Edit: Proof-of-concept:

import java.io.*;

public class TeeInputStream extends InputStream {
    private InputStream in;
    private OutputStream out;

    public TeeInputStream(InputStream in, OutputStream branch) {
        this.in=in;
        this.out=branch;
    }
    public int read() throws IOException {
        int read = in.read();
        if (read != -1) out.write(read);
        return read;
    }
    public void close() throws IOException {
        in.close();
        out.close();
    }
}

How to use it:

...
BufferedInputStream bis = new BufferedInputStream(is);
TeeInputStream tis = new TeeInputStream(bis,new FileOutputStream("test.mp3"));

BasicPlayer player = new BasicPlayer();
player.open(tis);
player.play();

score 0 · Answer 2 · answered Feb 15 '12 at 08:18

BufferedInputStream in = new BufferedInputStream(is);

OutputStream out = new BufferedOutputStream(new FileOutputStream(new File(savePathAndFilename)));  
    byte[] buf = new byte[256];  
    int n = 0;  
    while ((n=in.read(buf))>=0) {  
       out.write(buf, 0, n);  
    }  
    out.flush();  
    out.close();

score 0 · Answer 3 · answered Feb 15 '12 at 08:19

0

You can first write the stream to disk with FileInputStream. Then reload the stream from file.

answered Feb 15 '12 at 08:19

Summer_More_More_Tea

12,740
12
51
83

score 0 · Answer 4 · answered Feb 15 '12 at 08:35

Wrap you own InputStream

class myInputStream extends InputStream {

    private InputStream is;
    private FileOutputStream resFile;
    public myInputStream(InputStream is) throws FileNotFoundException {
        this.is = is;
        resFile = new FileOutputStream("path_to_result_file");
    }

    @Override
    public int read() throws IOException {
        int b = is.read();
        if (b != -1)
            resFile.write(b);
        return b;
    }

    @Override
    public void close() {
        try {
            resFile.close();
        } catch (IOException ex) {
        }
        try {
            is.close();
        } catch (IOException ex) {
        }
    }
}

and use

InputStream is = conn.getInputStream();
myInputStream myIs = new myInputStream(is);
BufferedInputStream bis = new BufferedInputStream(myIs);

Write mp3 file to disk while playing in Java

4 Answers4