I applied the example codes but it could not fit me. Here is my simplified solution in below;
public static void main(String[] args) {
mainScreen ms = new mainScreen();
ms.setVisible(true);
Gst.init(Version.BASELINE, "BasicPipeline");
pipeline = (Pipeline) Gst.parseLaunch("videotestsrc ! autovideosink");
GstVideoComponent vc = new GstVideoComponent();
// Missing a connection bw GstVideoComponent and pipeline
// The code on Swing Exapmle
//playbin = new PlayBin("playbin"); // Actually I have a pipeline instead
//playbin.setVideoSink(vc.getElement()); // pipeline have not method such
// setVideoSink
Element level = ElementFactory.make("level", "level");
//playbin.set("audio-filter", level);
// Panel that should run the pipeline inside.
// ms.videoPanel ??
ms.videoPanel.add(vc);
vc.setPreferredSize(new Dimension(800, 600));
pipeline.play(); // Opens a new window
Gst.main();
}