VLC and Processing

Marceau

Hi everyone,

I would like to create a little soft able to receive a VLC stream on a local network (via UDP or RTSP). But I really don't know how to start. I've tried to use this : (by David Shiffman)

import java.awt.image.*; 
import javax.imageio.*;
import java.io.ByteArrayInputStream;
import java.net.*;



// Port we are receiving.
int port = 9100; 
DatagramSocket ds; 
// A byte array to read into (max size of 65536, could be smaller)
byte[] buffer = new byte[65536]; 

PImage video;

void setup() {
  size(400,300);
  try {
    ds = new DatagramSocket(port);
  } catch (SocketException e) {
    e.printStackTrace();
  } 
  video = createImage(320,240,RGB);
}

 void draw() {
  // checkForImage() is blocking, stay tuned for threaded example!
  checkForImage();

  // Draw the image
  background(0);
  imageMode(CENTER);
  image(video,width/2,height/2);
}

void checkForImage() {
  DatagramPacket p = new DatagramPacket(buffer, buffer.length); 
  try {
    ds.receive(p);
  } catch (IOException e) {
    e.printStackTrace();
  } 
  byte[] data = p.getData();

  println("Received datagram with " + data.length + " bytes." );

  // Read incoming data into a ByteArrayInputStream
  ByteArrayInputStream bais = new ByteArrayInputStream( data );

  // We need to unpack JPG and put it in the PImage video
  video.loadPixels();
  try {
    // Make a BufferedImage out of the incoming bytes
    BufferedImage img = ImageIO.read(bais);
    // Put the pixels into the video PImage
    img.getRGB(0, 0, video.width, video.height, video.pixels, 0, video.width);
  } catch (Exception e) {
    e.printStackTrace();
  }
  // Update the PImage pixels
  video.updatePixels();
}

But it isn't working, it detect that something is streamed but there is a NullPointer error. So if any of you have an idea on how to fix it or how to do it using another way, fell free to tell me !

Thanks

koogs

there is a NullPointer error.

where?

and how do we run this code? we have the source but what else do we need to do to reproduce the error?

Marceau

You have to run the code, then to go on VLC and to stream a video file using UDP (using 127.0.0.1) and to choose the port 9001. The error will occur at this moment. Here is the error :

Received datagram with 65536 bytes.
java.lang.NullPointerException
    at VideoReceiver.checkForImage(VideoReceiver.java:77)
    at VideoReceiver.draw(VideoReceiver.java:49)
    at processing.core.PApplet.handleDraw(PApplet.java:2403)
    at processing.awt.PSurfaceAWT$12.callDraw(PSurfaceAWT.java:1527)
    at processing.core.PSurfaceNone$AnimationThread.run(PSurfaceNone.java:316)

Thanks for helping me !