public static void main(String[] args) throws IOException { long start = System.currentTimeMillis(); FileChannel rChannel = new RandomAccessFile("/media/scratch/CSI.S12E21.HDTV.x264-LOL.mp4", "r").getChannel(); FileChannel wChannel = new RandomAccessFile("/media/scratch/ThreeHundredFourtyThreeMB_2.mp4", "rw").getChannel(); IsoFile isoFile = new IsoFile(rChannel); HandlerBox hdlr = Path.getPath(isoFile, "/moov[0]/trak[0]/mdia[0]/hdlr[0]"); assert hdlr != null; hdlr.setName(RandomStringUtils.random(hdlr.getName().length())); isoFile.getBox(wChannel); rChannel.close(); wChannel.close(); System.err.println((System.currentTimeMillis() - start) + "ms"); new File("/media/scratch/ThreeHundredFourtyThreeMB_2.mp4").delete(); } }