Video Conferencing with NaradaBrokering

1
Video Conferencing with NaradaBrokering

• Mark Baker and Rahim Lakhoo

2
Outline

• Introduction
• Motivation
• Technologies
• GridSphere,
• Java Media Framework,
• NaradaBrokering.
• System Architecture
• Experiments
• Issues
• Conclusions

3
Introduction

• Portsmouth and Readings role in the Sakai VRE
  project is to develop and deploy a number of
  portlet-based tools and services.
• In particular we are looking at
• Collaborative tools based on NaradaBrokering,
• Semantic Web tools based on RDF,
• Bridging technologies to enable legacy
  applications,
• Peer-to-Peer technologies.
• Portsmouth and Reading are developing JSR-168
  portlets, on the basis that Sakai will consume
  portlets via the WSRP consumer developed within
  the project.
• In this talk we will recount our experiences
  developing, deploying and testing chat and video
  conferencing services based on NaradaBrokering,
  GridSphere and the Java Media Framework.

4
Collaborative Service

• Motivation
• Investigate NaradaBrokering that is also
  partially funded by the e-Science programme,
  which other UK Universities and organisations are
  interested.
• Add useful tools for the Sakai Demonstrator,
• To create a chat and video conferencing system
  that work-site users and external users may
  communicate with.
• To provide the ability to conference with many
  participants, i.e. meetings or teleconferences.
• Note this work was completed in Jan 2005.

5
Technologies Choices

• GridShpere
• Supports JSR-168 and WebSphere portlets,
• Provides a portal framework, not just a portal,
  but a development infrastructure.
• Has an active support and user community.
• NaradaBrokering
• Unified messaging framework with support for Grid
  and Web Services,
• Software multi-casting with support for different
  transport protocols,
• Supports video conferencing with Global-MMCS.
• Java Media Framework
• Java-based solution for handling time-sensitive
  data,
• Ability to capture video and compress streams in
  different formats,
• Supports the Real-Time Protocol.

6
Portals - GridSphere

• The GridSphere framework provides an open-source
  portlet-based Web portal.
• The framework allows developers to manage and
  deploy portlets within the container.
• GridSphere supports JSR-168 and WebSphere-based
  portlets.
• GridSphere also supports GridPortlets for
  managing jobs and data on the Grid.
• GridSphere uses Apache Tomcat as its container
  though it can also use Jetty.

7
Java Media Framework (JMF)

• JMF provides an interface for Java applications
  to interact with media or time sensitive data.
• JMF includes codecs and protocols, such as
• Support for Quick Time movies,
• MP3 playback,
• Video/audio capture,
• Supports the Real Time Protocol (RTP),
• H.263 video conferencing codec (compression
  format).
• JMF is available in two formats
• Performance Pack, for only Linux, Solaris and
  Windows
• Includes native libraries for codecs and
  capturing from devices,
• Platform Independent version
• Includes partial capability for codecs and no
  video capturing.

8
NaradaBrokering

• NaradaBrokering is developed by the Community
  Grids Lab at Indiana University.
• Originally designed to provide software
  multi-casting for real-time collaborative
  systems.
• Asynchronous messaging system that is JMS 1.02b
  compliant.
• Publish, subscribe and bind architecture with JMS
  topics.
• NaradaBrokering supports other capabilities
• Video Conferencing via Global-MMCS,
• Peer-to-Peer with JXTA,
• Grid and Web Services.
• Provides a number of transport protocols
• HTTP/HTTPS, TCP/NIO-TCP and UDP.

9
NB Chat and Video Architecture

• The NB Chat and Video System consists of
  portlets, portlet services and Java applets from
  a users perspective
• Chat portlet,
• Video Conferencing portlet,
• NaradaBrokering portlet service,
• Userlist portlet service,
• JMF applet.
• The servers consist of
• NaradaBrokering,
• Apache Tomcat,
• GridSphere,
• Global-MMCS.

10
System Architecture
11
The Chat Service (1)

• The Chat Service consists of
• A Chat portlet,
• A NaradaBrokering portlet service,
• A Userlist portlet service.
• The Chat portlet provides the interface and user
  notification messages.
• The NaradaBrokering portlet service, handles all
  connections and messages to be sent/received for
  all connected users.
• The Userlist portlet service tracks connected
  users and stores user information.

12
The Chat Service (2)
The User Interface
13
The Chat Service (3)
Configuration Interface
14
An Example System Set-up
15
The Chat Service (4)

• Each user has a PortletSession, which hold all
  connection information per a user.
• The Chat portlet and the NaradaBrokering portlet
  service use PortletSessions for the communication
  of messages and connection information.
• Messages are sent by the NaradaBrokering portlet
  service to a JMS Chat topic on the broker.
• Each user has an associated asynchronous
  MesaageListener, which stores any received
  messages inside their PortletSession.

16
The Video Service (1)

• The Video Service consists of
• A Video Conferencing portlet,
• JMF Applets,
• A Userlist portlet service.
• The Video Conferencing portlet displays a list of
  available cameras and loads the relevant JMF
  applet.
• The Userlist portlet provides the video stream
  topics and other details, to initiate the video
  conference.

17
The Video Service (2)
The Video Camera Subscription Interface
18
The Video Service (3)

• Users may publish a web-cam or subscribe to other
  registered web-cams.
• The video conferencing portlet gathers user
  information from the Userlist portlet service, to
  display a list of any available cameras.
• The video conferencing portlet generates an
  applet tag with the connection details.
• The applet then connects to a broker to
  initialise a video conference.

19
Video Service (4)

• There are two JMF applets
• A transmitting applet which captures a device,
• A receiving applet which displays a video stream.
• The transmitting applet captures a users Web-cam
  as RTP data and encapsulates it within the
  NaradaRTPConnector.
• The receiving applet uses the NaradaRTPConnector
  to extract the video stream and plays it with a
  JMF player.
• This means that only one UDP port is required to
  be open on the broker for users to use the video
  conferencing.
• The chat facility also only requires one TCP port
  on the broker.
• This is unlike VRVS or Access Grid which requires
  a range of ports to be open.

20
Chat and Video Services

• The presentation layers are separated from the
  logic an MVC design pattern.
• All inter-portlet communications are undertaken
  with either PortletSessions or via portlet
  services.
• The portlet services interact with external
  sources, while the portlets only deal with the
  layout and passing of information to the
  services.

21
NB Chat and Video System Experiment

• The Chat and Video Portlet was tested with four
  cameras and five users.
• Each participant was connected to the chat room
  and four cameras where published.
• All participants subscribed to all four cameras.
• To stress test the system all participants
  subscribed multiple times to all four cameras.
• The limitations of the number of subscriptions
  each user could make, was only limited by their
  system resources.
• The maximum obtained was 18 subscriptions with
  one published camera, by a single user.
• The broker and GridSphere consistently utilised
  500 MBytes of memory, peaking to 643 MBytes.

22
NB Chat and Video System Experiment
23
Issues

• The RTPLinkManager in NaradaBrokering (0.99RC4)
  has hardwired ports, even though there is a
  configuration file.
• NaradaBrokerings RTP session configuration file
  is not dynamic it requires a broker restart.
• When many messages are sent to the broker memory
  usage increases and eventually the broker fails.
• The system suffers from session bloating with
  this portlet and thus consumes a lot of memory.
• Memory is not reclaimed by the system.
• JMF has compatibility issues with web-cams and
  Linux.
• Refreshing the chat room messages automatically
  requires other technologies, such as AJAX and/or
  JavaScript.
• Closing the an applets connection is
  problematic needs the whole browser to be
  shutdown.

24
Conclusions

• As proof of concept the system does work,
  however, some of the technologies and standards
  need to mature.
• Installing JMF is still problematic for platforms
  other than Windows and seems to be a dormant
  project, with few updates.
• JSR-168 does not accommodate for the concept of
  portlet services, thus portlets could be very
  large and not easily reusable.
• NaradaBrokerings RTP support and JMS API needs
  to be extended to improve its capabilities.

25
References

• http//www.gridpshere.org
• http//www.naradabrokering.org
• http//java.sun.com/products/java-media/jmf/
• http//www.globalmmcs.org/
• http//java.sun.com/products/java-media/jmf/2.1.1/
  guide/JMFArchitecture.html
• http//www.javaworld.com/javaworld/jw-08-2003/jw-0
  801-portlet.html
• http//www-128.ibm.com/developerworks/websphere/li
  brary/techarticles/0312_hepper/hepper.html

26

• Questions?

http//dsg.port.ac.uk http//acet.rdg.ac.uk