I think it's a layout problem, you are adding the MediaPlayer component before the video was created, so it's preferred size is 0. Try to place the video in the border layout center so it's preferred size is ignored and the player will have enough space to display.
Try this:
final Form hi = new Form("Hi World");
hi.setLayout(new BorderLayout());
final Button bCapture = new Button("Capture Media");
bCapture.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ect) {
try {
final MediaPlayer mpPlayer = new MediaPlayer();
String value = Capture.captureVideo();
System.out.println("Captured Video " + value);
if (value != null) {
System.out.println("Playing Video");
InputStream is = FileSystemStorage.getInstance().openInputStream(value);
String strMime = "video/mp4";
System.out.println("Input Stream" + is.available());
mpPlayer.setName("bla");
mpPlayer.setDataSource(is, strMime, new Runnable() {
public void run() {
System.out.println("reset the clip for playback");
}
});
hi.addComponent(BorderLayout.CENTER, mpPlayer);
hi.revalidate();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
);
hi.addComponent(BorderLayout.NORTH, bCapture);
hi.show();