CTD bug in simple video streaming applet.

Question

I'm trying to write a simple applet to use JMF to allow an end-user to view a video stream that's being served up by VLC. It doesn't have to look immensely pretty (in fact, streamlined is what I want most). I swiped some code from the jicyshout project (http://jicyshout.sourceforge.net) which handles streaming MP3s, and borrowed a framework for an applet from one of Sun's example applets for the JMF.
Here's my code so far:
** begin file SimpleVideoDataSource.java **
import java.lang.String;
import java.net.*;
import java.io.*;
import java.util.Properties;
import javax.media.*;
import javax.media.protocol.*;
/* The SeekableStream and DataSource tweaks are based on the code from
* jicyshout (jicyshout.sourcefourge.net), which was written by Chris Adamson.
* The code was simplified (no need for mp3 metadata here), cleaned up, then
* extended for our puposes.
* This is a DataSource using a SeekableStream suitable for
* streaming video using the default parser supplied by JMF.
public class SimpleVideoDataSource extends PullDataSource {
protected MediaLocator myML;
protected SeekableInputStream[] seekStreams;
protected URLConnection urlConnection;
// Constructor (trivial).
public SimpleVideoDataSource (MediaLocator ml) throws MalformedURLException {
super ();
myML = ml;
URL url = ml.getURL();
public void connect () throws IOException {
try {
URL url = myML.getURL();
urlConnection = url.openConnection();
// Make the stream seekable, so that the JMF parser can try to parse it (instead
// of throwing up).
InputStream videoStream = urlConnection.getInputStream();
seekStreams = new SeekableInputStream[1];
seekStreams[0] = new SeekableInputStream(videoStream);
} catch (MalformedURLException murle) {
throw new IOException ("Malformed URL: " + murle.getMessage());
} catch (ArrayIndexOutOfBoundsException aioobe) {
fatalError("Array Index OOB: " + aioobe);
// Closes up InputStream.
public void disconnect () {
try {
seekStreams[0].close();
} catch (IOException ioe) {
System.out.println ("Can't close stream. Ew?");
ioe.printStackTrace();
// Returns just what it says.
public String getContentType () {
return "video.mpeg";
// Does nothing, since this is a stream pulled from PullSourceStream.
public void start () {
// Ditto.
public void stop () {
// Returns a one-member array with the SeekableInputStream.
public PullSourceStream[] getStreams () {
try {
// **** This seems to be the problem. ****
if (seekStreams != null) {
return seekStreams;
} else {
fatalError("sourceStreams was null! Bad kitty!");
return seekStreams;
} catch (Exception e) {
fatalError("Error in getStreams(): " + e);
return seekStreams;
// Duration abstract stuff. Since this is a theoretically endless stream...
public Time getDuration () {
return DataSource.DURATION_UNBOUNDED;
// Controls abstract stuff. No controls supported here!
public Object getControl (String controlName) {
return null;
public Object[] getControls () {
return null;
void fatalError (String deathKnell) {
System.err.println(":[ Fatal Error ]: - " + deathKnell);
throw new Error(deathKnell);
** end file SimpleVideoDataSource.java **
** begin file SeekableInputStream.java **
import java.lang.String;
import java.net.*;
import java.io.*;
import java.util.Properties;
import javax.media.*;
import javax.media.protocol.*;
/* The SeekableStream and DataSource tweaks are based on the code from
* jicyshout (jicyshout.sourcefourge.net), which was written by Chris Adamson.
* The code was simplified (no need for mp3 metadata here), cleaned up, then
* extended for our puposes.
/* This is an implementation of a SeekableStream which extends a
* BufferedInputStream to basically fake JMF into thinking that
* the stream is seekable, when in fact it's not. Basically, this
* will keep JMF from puking over something it expects but can't
* actually get.
public class SeekableInputStream extends BufferedInputStream implements PullSourceStream, Seekable {
protected int tellPoint;
public final static int MAX_MARK = 131072; // Give JMF 128k of data to "play" with.
protected ContentDescriptor unknownCD;
// Constructor. Effectively trivial.
public SeekableInputStream (InputStream in) {
super (in, MAX_MARK);
tellPoint = 0;
mark (MAX_MARK);
unknownCD = new ContentDescriptor ("unknown");
// Specified size constructor.
public SeekableInputStream (InputStream in, int size) {
super (in, Math.max(size, MAX_MARK));
tellPoint = 0;
mark(Math.max(size, MAX_MARK));
unknownCD = new ContentDescriptor ("unknown");
// Reads a byte and increments tellPoint.
public int read () throws IOException {
int readByte = super.read();
tellPoint++;
return readByte;
// Reads bytes (specified by PullSourceStream).
public int read (byte[] buf, int off, int len) throws IOException {
int bytesRead = super.read (buf, off, len);
tellPoint += bytesRead;
return bytesRead;
public int read (byte[] buf) throws IOException {
int bytesRead = super.read (buf);
tellPoint += bytesRead;
return bytesRead;
// Returns true if in.available() <= 0 (that is, if there are no bytes to
// read without blocking or end-of-stream).
public boolean willReadBlock () {
try {
return (in.available() <= 0);
} catch (IOException ioe) {
// Stick a fork in it...
return true;
// Resets the tellPoint to 0 (meaningless after you've read one buffer length).
public void reset () throws IOException {
super.reset();
tellPoint = 0;
// Skips bytes as expected.
public long skip (long n) throws IOException {
long skipped = super.skip(n);
tellPoint += skipped;
return skipped;
// Trivial.
public void mark (int readLimit) {
super.mark (readLimit);
// Returns the "unknown" ContentDescriptor.
public ContentDescriptor getContentDescriptor () {
return unknownCD;
// Lengths? We don't need no stinkin' lengths!
public long getContentLength () {
return SourceStream.LENGTH_UNKNOWN;
// Theoretically, this is always false.
public boolean endOfStream () {
return false;
// We don't provide any controls, either.
public Object getControl (String controlName) {
return null;
public Object[] getControls () {
return null;
// Not really... but...
public boolean isRandomAccess () {
return true;
// This only works for the first bits of the stream, while JMF is attempting
// to figure out what the stream is. If it tries to seek after that, bad
// things are going to happen (invalid-mark exception).
public long seek (long where) {
try {
reset();
mark(MAX_MARK);
skip(where);
} catch (IOException ioe) {
ioe.printStackTrace();
return tell();
// Tells where in the stream we are, adjusted for seeks, resets, skips, etc.
public long tell () {
return tellPoint;
void fatalError (String deathKnell) {
System.err.println(":[ Fatal Error ]: - " + deathKnell);
throw new Error(deathKnell);
** end file SeekableInputStream.java **
** begin file StreamingViewerApplet.java **
* This Java Applet will take a streaming video passed to it via the applet
* command in the embedded object and attempt to play it. No fuss, no muss.
* Based on the SimplePlayerApplet from Sun, and uses a modified version of
* jicyshout's (jicyshout.sourceforge.net) tweaks to get JMF to play streams.
* Use it like this:
* <!-- Sample HTML
* <APPLET CODE="StreamingViewerApplet.class" WIDTH="320" HEIGHT="240">
* <PARAM NAME="code" VALUE="StreamingViewerApplet.class">
* <PARAM NAME="type" VALUE="application/x-java-applet;version=1.1">
* <PARAM NAME="streamwidth" VALUE="width (defaults to 320, but will resize as per video size)">
* <PARAM NAME="streamheight" VALUE="height (defaults to 240, but will resize as per video size)">
* <PARAM NAME="stream" VALUE="insert://your.stream.address.and:port/here/">
* </APPLET>
* -->
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.lang.String;
import java.lang.ArrayIndexOutOfBoundsException;
import java.net.URL;
import java.net.MalformedURLException;
import java.net.*;
import java.io.*;
import java.io.IOException;
import java.util.Properties;
import javax.media.*;
import javax.media.protocol.*;
public class StreamingViewerApplet extends Applet implements ControllerListener {
Player player = null;
Component visualComponent = null;
SimpleVideoDataSource dataSource;
URL url;
MediaLocator ml;
Panel panel = null;
int width = 0;
static int DEFAULT_VIDEO_WIDTH = 320;
int height = 0;
static int DEFAULT_VIDEO_HEIGHT = 240;
String readParameter = null;
// Initialize applet, read parameters, create media player.
public void init () {
try {
setLayout(null);
setBackground(Color.white);
panel = new Panel();
panel.setLayout(null);
add(panel);
// Attempt to read width from applet parameters. If not given, use default.
if ((readParameter = getParameter("streamwidth")) == null) {
width = DEFAULT_VIDEO_WIDTH;
} else {
width = Integer.parseInt(readParameter);
// Ditto for height.
if ((readParameter = getParameter("streamheight")) == null) {
height = DEFAULT_VIDEO_HEIGHT;
} else {
height = Integer.parseInt(readParameter);
panel.setBounds(0, 0, width, height);
// Unfortunately, this we can't default.
if ((readParameter = getParameter("stream")) == null) {
fatalError("You must provide a stream parameter!");
try {
url = new URL(readParameter);
ml = new MediaLocator(url);
dataSource = new SimpleVideoDataSource(ml);
} catch (MalformedURLException murle) {
fatalError("Malformed URL Exception: " + murle);
try {
dataSource.connect();
player = Manager.createPlayer(dataSource);
} catch (IOException ioe) {
fatalError("IO Exception: " + ioe);
} catch (NoPlayerException npe) {
fatalError("No Player Exception: " + npe);
if (player != null) {
player.addControllerListener(this);
} else {
fatalError("Failed to init() player!");
} catch (Exception e) {
fatalError("Error opening player. Details: " + e);
// Start stream playback. This function is called the
// first time that the applet runs, and every time the user
// re-enters the page.
public void start () {
try {
if (player != null) {
player.realize();
while (player.getState() != Controller.Realized) {
Thread.sleep(100);
// Crashes... here?
player.start();
} catch (Exception e) {
fatalError("Exception thrown: " + e);
public void stop () {
if (player != null) {
player.stop();
player.deallocate();
} else {
fatalError("stop() called on a null player!");
public void destroy () {
// player.close();
// This controllerUpdate function is defined to implement a ControllerListener
// interface. It will be called whenever there is a media event.
public synchronized void controllerUpdate(ControllerEvent event) {
// If the player is dead, just leave.
if (player == null)
return;
// When the player is Realized, get the visual component and add it to the Applet.
if (event instanceof RealizeCompleteEvent) {
if (visualComponent == null) {
if ((visualComponent = player.getVisualComponent()) != null) {
panel.add(visualComponent);
Dimension videoSize = visualComponent.getPreferredSize();
width = videoSize.width;
height = videoSize.height;
visualComponent.setBounds(0, 0, width, height);
} else if (event instanceof CachingControlEvent) {
// With streaming, this doesn't really matter much, does it?
// Without, a progress bar of some sort would be appropriate.
} else if (event instanceof EndOfMediaEvent) {
// We should never see this... but...
player.stop();
fatalError("EndOfMediaEvent reached for streaming media. ewe ewe tea eff?");
} else if (event instanceof ControllerErrorEvent) {
player = null;
fatalError(((ControllerErrorEvent)event).getMessage());
} else if (event instanceof ControllerClosedEvent) {
panel.removeAll();
void fatalError (String deathKnell) {
System.err.println(":[ Fatal Error ]: - " + deathKnell);
throw new Error(deathKnell);
** end file StreamingViewerApplet.java **
Now, I'm still new to the JMF, so this might be obvious to some of you... but it's exploding on me, and crashing to desktop (both in IE and Firefox) with some very fun errors:
# An unexpected error has been detected by HotSpot Virtual Machine:
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x21217921, pid=3200, tid=3160
# Java VM: Java HotSpot(TM) Client VM (1.5.0_06-b05 mixed mode, sharing)
# Problematic frame:
# C 0x21217921
--------------- T H R E A D ---------------
Current thread (0x058f7280): JavaThread "JMF thread: com.sun.media.amovie.AMController@506411[ com.sun.media.amovie.AMController@506411 ] ( realizeThread)" [_thread_in_native, id=3160]
siginfo: ExceptionCode=0xc0000005, writing address 0x034e6360
(plenty more here, I can post the rest if necessary)
The problem seems to be coming from the "return seekStreams" statement in the first file; when I have execution aborted before that (with a fatalError call), it doesn't crash.
Any tips/hints/suggestions?

Answer 1

You should write your own Applet, where you can easily get the visual component (getVisualComponent())and show it directly in your Applet (you call it "embedded"). As far as I know, all examples (AVReceive* etc.) use the component which opens a new window.
Best regards from Germany,
r.v.