[LayaAir3]3.3 native视频节点使用报错，无法播放视频

错误信息：
08-08 18:50:56.416  2554  2589 I LayaVideo: [Debug][Video]SetAutoplay: SetAutoPlay
08-08 18:50:56.420  2554  2589 I LayaVideo: [Debug][Video]setVolume: 100
08-08 18:50:56.420  2554  2589 W System.err: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.setVolume(float, float)' on a null object reference
08-08 18:50:56.420  2554  2589 W System.err:    at layaair.game.browser.LayaVideoPlayer.setVolume(LayaVideoPlayer.java:427)
08-08 18:50:56.420  2554  2589 W System.err:    at layaair.game.browser.ConchJNI.performUpdates(Native Method)
08-08 18:50:56.420  2554  2589 W System.err:    at layaair.game.browser.ConchSurfaceView$GLThread.run(ConchSurfaceView.java:116)