Android - Dark VideoView in Dialog

I'm having a problem while viewing a video within a Dialog using VideoView. The video plays perfectly but the region within this Dialog is too dark. I tried several things but it did not work.

Code:

Dialog dialog = new Dialog(MainActivity.this);
                dialog.setTitle("Titulo");
                dialog.setContentView(R.layout.broadcaster);
                dialog.show();
                VideoView screen = (VideoView)dialog.findViewById(R.id.screen);
                Uri video = Uri.parse(URL);
                MediaController mc = new MediaController(MainActivity.this);
                mc.setAnchorView(screen);
                mc.setMediaPlayer(screen);
                screen.setMediaController(mc);
                screen.setVideoURI(video);

                screen.start();