Problem in video capture at server and fetching by client

Question

hi
I am doing final year project it has server at one end which is connected to video capturing device-webcam in my case
and the client is mobile.
I want the live video captured be transmitted to the mobile client on fetch video request.
I have tried implementing it but facing some problems so would like to know the reason behing and also ask if the way i am following is correct or not
At server end i tried to extract frame as follows:
//the datasource handler class is as follows
      * Inner class MyDSHandler takes the Output DataSource form the
      * Processor and extracts the frame from it.
      * It implements the BufferTransferHandler so that it can receive
      * Buffer from the PushBufferStream.
     public class MyDSHandler implements BufferTransferHandler
          DataSource source;
          PullBufferStream pullStrms[] = null;
          PushBufferStream pushStrms[] = null;
          //Buffer readBuffer = null;
          int i = 1, j = 1;
          * Sets the media source this MediaHandler should use to obtain content.
          * @param source the DataSource from the Processor
          private void setSource(DataSource source) throws IncompatibleSourceException
               // Different types of DataSources need to handled differently.
               if(source instanceof PushBufferDataSource)
                    pushStrms = ((PushBufferDataSource) source).getStreams();
                    // Set the transfer handler to receive pushed data from the push DataSource.
                    //pushStrms[0] since we need to handle only the video stream
                    pushStrms[0].setTransferHandler(this);
               else if(source instanceof PullBufferDataSource)
                    System.out.println("PullBufferDataSource!");
                    // This handler only handles push buffer datasource.
                    throw new IncompatibleSourceException();
               this.source = source;
               readBuffer = new Buffer();
          * This will get called when there's data pushed from the PushBufferDataSource.
          * @param stream the PushBufferStream obtained from the DataSource
          public void transferData(PushBufferStream stream)
               try
                    stream.read(readBuffer);
               catch(Exception e)
                    System.out.println(e);
                    return;
               if((readBuffer == null) || (readBuffer.getLength() == 0))
                    System.out.println("Null or Empty buffer encountered..");
                    return;
               // Just in case contents of data object changed by some other thread
               Buffer inBuffer = (Buffer)(readBuffer.clone());
               // Check for end of stream
               if(readBuffer.isEOM())
                    System.out.println("End of stream");
                    return;
                * we can apply frame control here by deciding whether to process
                * the frame or not
               processBuffer2(inBuffer);
          public void start()
               try{source.start();}catch(Exception e){System.out.println(e);}
          public void stop()
               try{source.stop();}catch(Exception e){System.out.println(e);}
          public void close(){stop();}
          public Object[] getControls()
               return new Object[0];
          public Object getControl(String name)
               return null;
           * Processes the Buffer , i.e converts it into an image and
           * transfer its content via Socket
           * @param inBuffer the buffer received from the PushBufferStream
          public void processBuffer2(Buffer inBuffer)
          {         //extracting frame from video and writing image on stream
               //RGBFormat format  = (RGBFormat)inBuffer.getFormat();
               System.out.println(inBuffer.getLength());
               YUVFormat format = (YUVFormat)inBuffer.getFormat();
               Image img = (new BufferToImage(format)).createImage(inBuffer);
               BufferedImage bimg = (BufferedImage)img;
               if(bimg != null)
                    try
                          * encodes the image in the JPEG format and writes it to
                          * the socket
                         ImageIO.write(bimg, "jpg", clientOut);
                         System.out.println("Data Written to stream");
                         logArea.append("\n Image Data Written to Stream");
                    catch(Exception e)
                         System.out.println(e);
     }and how can one control the frame rate of the video like if i require the speed of 7 frames per second and the resolution
also
i am trying to convert the frame fetched to jpeg and at client , tried making use of jpeg image property by detecting the img start and end by reading the image data in bytes from the inputstream (0xffd8 as strt of image and 0xffd9 as end)
  byte[] img_data = new byte[4*1024];//buffer to read and hold one image info
try
                while((data = dis.read()) != -1)
                    //System.out.print(Integer.toHexString(data));
                    if(data == 0xFF)
                        fm = true;
                    else if(fm)
                        if(data == 0xD8)
                            //start of the image
                            System.out.print("Start of image found  : ");
                            //ctr should be zero at this stage here
                            //writing to byte[]
                            img_data[ctr] = (byte)0xFF;
                            ctr++;
                            img_data[ctr] = (byte)0xD8;
                            ctr++;
                        else if(data == 0xD9)
                            //end of image
                            //writing to byte[]
                            img_data[ctr] = (byte)0xFF;
                            ctr++;
                            img_data[ctr] = (byte)0xD9;
                            ctr++;
                            // consrtucting image from the byte[]
                            img = Image.createImage(img_data, 0, ctr-1);
                            if(img != null)
                                repaint();
                                System.out.println("Image drawn");
                            else
                                System.out.println("Image is null");
                                /*try
                                    Thread.sleep(500);
                                catch(Exception e)
                            ctr = 0;  // ctr back to zero for the new image
                            //break;
                        else
                            //writing to byte[]
                            img_data[ctr] = (byte)0xFF;
                            ctr++;
                            img_data[ctr] = (byte)data;
                            ctr++;
                        fm = false;
            catch(Exception e){}
    }The problem i am facing is the client gets the black image just for a fraction of second and then the application hangs and no video is visible.
I have very little time left to complete this project as deadline is very close
please would be very grateful if guided timely.

Answer 1

equator07 wrote:
Thanks for the reply.
i saw in recent posts some protocols had been made use of like rtp i am not making use of any of these
will it effect?I can see that you're not using RTP... and "will it effect?" doesn't make any sense AT ALL...
is the way i have made use of jmf correct?There's no correct way to use an API... but no, you're not doing things in even remotely a "tradional" way...
*like the way i am extracting the frame,
and how can i set the resolution of the video taken by cam and adjust the frame rate?*I have no idea if your code works. I assume that you would have tested it, and proved it to either be producing a valid JPEG image or not. If you've not done that testing, then you obviously need to.
because i want live video to be seen at client end i am seriously confused and the progress as just come to an hault at this point and am in real need of guidance.You should probably be using RTP and the tradional way of using JMF then...
[http://forums.sun.com/thread.jspa?messageID=10930286#10930286]
Read through all of the links I gave the person on the above thread and you'll be on a lot better footing as far as using JMF goes.
shall i send the server side code.Till now server and client are both on local host.No, I don't need to see any more of your code. I'm not a proof reader, and I'm not going to debug it for you. Do you own work.