通过vlcj进行的剪切与请求的间隔不匹配

Question

请看一下这段代码示例。它应该从一个样本视频（30到40）减少10秒。

public Example() {
    factory = new MediaPlayerFactory();
    mediaPlayer = factory.newHeadlessMediaPlayer();
}

public void start(Semaphore semaphore) {

    String fileName =  "/home/damian/Videos/SampleVideo_1080x720_30mb.mp4";
    Media media = new SimpleMedia(fileName);
    mediaPlayer.playMedia(fileName, ":start-time=30", ":stop-time=40", ":sout=#transcode{vcodec=h264,vb=4096,scale=1,acodec=mpga,ab=128,channels=2,samplerate=44100}:duplicate{dst=file{dst=" + "/home/damian/vout/v.mp4" + "}}");
    mediaPlayer.addMediaPlayerEventListener(new MediaPlayerEventAdapter() {
        @Override
        public void finished(MediaPlayer mediaPlayer) {
            mediaPlayer.stop();
            mediaPlayer.release();
            semaphore.release();
        }
    });

结果的问题是它总是在开始时包含0.5秒的初始​​样本。所以眨眼之间，我可以看到原始视频的开始，然后是10秒请求。有谁知道如何摆脱这个问题？