Как с помощью Java резать mp3 файлы?

Сделал 2-й метод:

public class Cutter {
    public Cutter(FileInputStream in, int start, int len) throws IOException, BitstreamException, DecoderException
    {
        FileOutputStream output = new FileOutputStream("tmp.mp3");
        Decoder decode = new Decoder();
        Bitstream bStream = new Bitstream(in);
        Header head = bStream.readFrame();
        decode.decodeFrame(head, bStream);
        try{
            byte[] arr1 = new byte[bStream.getRawID3v2().available()];
            bStream.getRawID3v2().read(arr1);
            output.write(arr1);
        }
        catch(NullPointerException ex) {}
        //time in MS
        int timeMS = (len + 1) * 1000;
        //Number of frames for cut
        int numberOfFrames = timeMS / (int)head.ms_per_frame();
        //number of bytes
        int numberOfBytesToCut = numberOfFrames  * head.framesize;
        //number bytes to skip
        int numberBytesToSkip = ((start + 1) * 1000) / (int)head.ms_per_frame() * head.framesize;
        byte[] arr = new byte[in.available()];
        in.skip(numberBytesToSkip);
        in.read(arr);
        output.write(arr, 0, numberOfBytesToCut);
        output.close();
    }
}