capturing video from ip camera

问题

I am trying to capture video from ip camera into my application , its giving exception

com.sun.image.codec.jpeg.ImageFormatException: Not a JPEG file: starts with 0x0d 0x0a
    at sun.awt.image.codec.JPEGImageDecoderImpl.readJPEGStream(Native Method)
    at sun.awt.image.codec.JPEGImageDecoderImpl.decodeAsBufferedImage(Unknown Source)
    at test.AxisCamera1.readJPG(AxisCamera1.java:130)
    at test.AxisCamera1.readMJPGStream(AxisCamera1.java:121)
    at test.AxisCamera1.readStream(AxisCamera1.java:100)
    at test.AxisCamera1.run(AxisCamera1.java:171)
    at java.lang.Thread.run(Unknown Source)

its giving exception at image = decoder.decodeAsBufferedImage();

Here is the code i am trying

private static final long serialVersionUID = 1L;
    public boolean useMJPGStream = true;
    public String jpgURL = "http://ip here/video.cgi/jpg/image.cgi?resolution=640×480";
    public String mjpgURL = "http://ip here /video.cgi/mjpg/video.cgi?resolution=640×480";
    DataInputStream dis;
    private BufferedImage image = null;
    public Dimension imageSize = null;
    public boolean connected = false;
    private boolean initCompleted = false;
    HttpURLConnection huc = null;
    Component parent;

    /** Creates a new instance of AxisCamera */
    public AxisCamera1(Component parent_) {
        parent = parent_;
    }

    public void connect() {
        try {
            URL u = new URL(useMJPGStream ? mjpgURL : jpgURL);
            huc = (HttpURLConnection) u.openConnection();

            // System.out.println(huc.getContentType());
            InputStream is = huc.getInputStream();

            connected = true;
            BufferedInputStream bis = new BufferedInputStream(is);
            dis = new DataInputStream(bis);
            if (!initCompleted)
                initDisplay();
        } catch (IOException e) { // incase no connection exists wait and try
                                    // again, instead of printing the error
            try {
                huc.disconnect();
                Thread.sleep(60);
            } catch (InterruptedException ie) {
                huc.disconnect();
                connect();
            }
            connect();
        } catch (Exception e) {
            ;
        }
    }

    public void initDisplay() { // setup the display
        if (useMJPGStream)
            readMJPGStream();
        else {
            readJPG();
            disconnect();
        }
        imageSize = new Dimension(image.getWidth(this), image.getHeight(this));
        setPreferredSize(imageSize);
        parent.setSize(imageSize);
        parent.validate();
        initCompleted = true;
    }

    public void disconnect() {
        try {
            if (connected) {
                dis.close();
                connected = false;
            }
        } catch (Exception e) {
            ;
        }
    }

    public void paint(Graphics g) { // used to set the image on the panel
        if (image != null)
            g.drawImage(image, 0, 0, this);
    }

    public void readStream() { // the basic method to continuously read the
                                // stream
        try {
            if (useMJPGStream) {
                while (true) {

                    readMJPGStream();
                    parent.repaint();
                }
            } else {
                while (true) {
                    connect();
                    readJPG();
                    parent.repaint();
                    disconnect();

                }
            }

        } catch (Exception e) {
            ;
        }
    }

    public void readMJPGStream() { // preprocess the mjpg stream to remove the
                                    // mjpg encapsulation
        readLine(3, dis); // discard the first 3 lines
        readJPG();
        readLine(2, dis); // discard the last two lines
    }

    public void readJPG() { // read the embedded jpeg image
        try {


            JPEGImageDecoder decoder = JPEGCodec.createJPEGDecoder(dis);
            image = decoder.decodeAsBufferedImage();

        } catch (Exception e) {
            e.printStackTrace();
            disconnect();
        }

    }

    public void readLine(int n, DataInputStream dis) { // used to strip out the
                                                        // header lines
        for (int i = 0; i < n; i++) {
            readLine(dis);
        }
    }

    public void readLine(DataInputStream dis) {
        try {
            boolean end = false;
            String lineEnd = "\n"; // assumes that the end of the line is marked
                                    // with this
            byte[] lineEndBytes = lineEnd.getBytes();
            byte[] byteBuf = new byte[lineEndBytes.length];

            while (!end) {
                dis.read(byteBuf, 0, lineEndBytes.length);
                String t = new String(byteBuf);
                System.out.print(t); // uncomment if you want to see what the
                                        // lines actually look like
                if (t.equals(lineEnd))
                    end = true;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public void run() {
        System.out.println("in Run...................");
        connect();
        readStream();
    }

    @SuppressWarnings("deprecation")
    public static void main(String[] args) {


        JFrame jframe = new JFrame();
        jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        AxisCamera1 axPanel = new AxisCamera1(jframe);
        new Thread(axPanel).start();
        jframe.getContentPane().add(axPanel);
        jframe.pack();
        jframe.show();
    }

}

Any suggestions what I am doing wrong here??

回答1:

jpeg magic code is "0xff 0xd8" and not "0x0d 0x0a" (see [1]), that why your code fails. Maybe your code part which strips lines in readMJPGStream() is to hungry :)

[1] http://en.wikipedia.org/wiki/JPEG

来源：https://stackoverflow.com/questions/11186105/capturing-video-from-ip-camera