// https://stackoverflow.com/a/48214101

// sudo apt install vlc-plugin-access-extra !!!

!7

lib 1400526 // vlcj player (stable version for VLCJ 3)
lib 1400527 // vlcj 3
lib 1400528 lib 1400529 // jna
sS megaLibID = #1400525;

import uk.co.caprica.vlcj.player.*;
import uk.co.caprica.vlcj.player.direct.*;
import uk.co.caprica.vlcj.player.direct.format.*;

static BufferedImage image;
static MediaPlayerFactory factory;
static DirectMediaPlayer mediaPlayer;
static int width, height;

static FPSCounter fps;

p {
  pnl(pairToList(addMegaLibrary(myClassLoader(), megaLibID)));
  fixContextClassLoader();

  width = screenWidth();
  height = screenHeight();
  print(width + "/" + height);
  
  image = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration().createCompatibleImage(width, height);
  
  image.setAccelerationPriority(1.0f);

  String mrl = "screen://";
  String[] options = {
          ":screen-fps=30",
          ":live-caching=0",
          ":screen-width=" + width,
          ":screen-height=" + height,
          ":screen-left=0",
          ":screen-top=0"
  };
  pnl(options);
  factory = new MediaPlayerFactory();
  mediaPlayer = factory.newDirectMediaPlayer(new TestBufferFormatCallback(), new TestRenderCallback());
  mediaPlayer.playMedia(mrl, options);
}

// Callbacks are required.
sclass TestRenderCallback extends RenderCallbackAdapter {
  public TestRenderCallback() {
    super(((DataBufferInt) image.getRaster().getDataBuffer()).getData());
  }

  @Override
  public void onDisplay(DirectMediaPlayer mediaPlayer, int[] data) {
    if (fps == null) fps = new FPSCounter;
    fps.inc();
    print("Got image data (" + n2(l(data)) + ") - " + fps! + " fps");
    
    // The image data could be manipulated here...

    /* RGB to GRAYScale conversion example */
//            for(int i=0; i < data.length; i++){
//                int argb = data[i];
//                int b = (argb & 0xFF);
//                int g = ((argb >> 8 ) & 0xFF);
//                int r = ((argb >> 16 ) & 0xFF);
//                int grey = (r + g + b + g) >> 2 ; //performance optimized - not real grey!
//                data[i] = (grey << 16) + (grey << 8) + grey;
//            }
//            imagePane.repaint();
  }
}

sclass TestBufferFormatCallback implements BufferFormatCallback {
  @Override
  public BufferFormat getBufferFormat(int sourceWidth, int sourceHeight) {
      return new RV32BufferFormat(width, height);
  }
}

Began life as a copy of #1033431