[Java] PlayerEndpoint miss audio at the beginning of video

[minhnq1990]

I am in a PlayerEndpoint problem, can anyone help me please?
I have a simple program, that based on HelloWorld java example. I added a PlayerEndpoint so I can play a video before showing the loopback WebRTC. The video plays as expected, but it usually missing audio at beginning of video (silent about 1s-5s of video at the beginning, i.e: no audio in that starting duration), I tried difference video formats in mp4/avi/webm.
Here is my code:

    PlayerEndpoint player = new PlayerEndpoint.Builder(pipeline, VIDEO_PATH + videoName).build();

    WebRtcEndpoint webRtcEp = users.get(session.getId()).getWebRtcEndpoint();
    player.connect(webRtcEp, MediaType.AUDIO);
    player.connect(webRtcEp, MediaType.VIDEO);

    player.play();

I have searched in this Discussions and in the old Google Group, but neither can help.
So please can anyone help me troubleshooting this problem?
Thank you very much for any idea.