Access Grid Integration

1
Access Grid Integration

• Chris Greenhalgh
• University of Nottingham

2
Contents

• What is the Access Grid?
• How is the Access Grid (v.2.3) implemented?
• Integration Options
• A VR Access Grid client
• Integrating the e-science-GS system
• Conclusions future work

3
What is the Access Grid goals

• Distributed collaboration between multiple
  co-located groups
• Turnkey operation by non-computer scientists (?!)
  
• Analogous with co-located working
• Rich media (e.g. better than video-conferencing)
• Adequate security

4
What is the Access Grid in use
5
What is the Access Grid in use

• Local nodes usually meeting rooms
• Multi-party audio and video conferencing
• Echo cancelled (mono) audio
• 1-4 cameras and tiled data projectors for approx.
  life-size video
• A simple virtual room metaphor
• Several nodes join the same virtual venue in
  order to work together
• A few simple shared applications
• Presentation, web browser, image browser
• Some degree of authentication and access control

6
How is the Access Grid (v.2.3) implemented?
Venue Server
Venue Data n
Virtual Venue
Venue Event bus
Venue client
Node manager
Local App n
Service Manager Vic (video)
Service Manager Rat (audio)
User Data n
Shared App n
Mics speakers
Cameras Video windows
7
Joining a venue
Venue Server
Venue Data n
Virtual Venue
Venue Event bus
1. Join
Venue client
2. Streams
Node manager
Local App n
Service Manager Vic (video)
Service Manager Rat (audio)
User Data n
Shared App n
3. Exec rat
3. Exec vic
Mics speakers
Cameras Video windows
8
Running a shared application
Venue Server
Venue Data n
Virtual Venue
Venue Event bus
1. Get info (Join)
4.events
Venue client
Node manager
Local App n
3. get/set state
Service Manager Vic (video)
Service Manager Rat (audio)
2. start
User Data n
Shared App n
Mics speakers
Cameras Video windows
9
Sharing data
Venue Server
Venue Data n
1. create/2. get
Virtual Venue
Venue Event bus
1. Get info (Join) / Save data 2. Get data
Venue client
Node manager
Local App n
3. start
Service Manager Vic (video)
Service Manager Rat (audio)
User Data n
Shared App n
Mics speakers
Cameras Video windows
10
Integration Options (1)

• Share service URL or data via venue
• E.g.
• EQUIP server or rendezvous URL done
• Configuration file
• VRML model
• Data set
• Install and configure local service(s) at each
  node to handle that MIME type

11
Integration Options (2)

• Implement a new shared application
• Install shared application at each node to handle
  that MIME type
• Note,
• current implementation is all in Python
• Uses non-standard WS over GSI protocol to talk to
  venue service and other over GSI protocol to talk
  to event service

12
Integration Options (3)

• Implement a new node service
• Install on each node
• ?Define additional streams/stream types
• Not sure if this requires changes to venue server
  code
• Note,
• Again, all in python
• But rat/vic services can act as template for a
  service that execs another application
• done

13
Integration Options (4)

• Out-of-band use of same multicast streams
• Multicast groups, ports, protocols
• done

14
A VR Access Grid client

• Goals
• A 3D OpenGL-based vic (AG video) viewer
• Can be used with Chromium for local distribution
  and multi-screen display
• For standalone use in immersive interfaces
• Such as Reality Centres CAVEs
• For integration with other 3D interfaces to
  integrate content and communication
• E.g. collaborative 3D model viewer

15
VR Access Grid client

• Conversion of vic to a DLL, with API to access
  current streams and decoded images
• C OpenGL, and Java Java3D clients
• Fixes and enhancements to Chromium
• E.g, image warping and blending for use in
  Reality Centre
• Sample

16
(No Transcript)
17
Chromium Distribution Issues

• Standard use
• Stream video textures over network from
  application to each Chromium display server
• Enhancement
• Chromium SPU (Stream Processor Unit) with
  embedded vic receives multicast video at each
  server and uses locally in place of
• Stream identifiers embedded in compact fake
  textures by application

18
Chromium distribution issues
Standard
With video texture SPU
application
vic
application
vic
video
video
chromium
chromium
OnlyStream IDs over TCP
Textures over TCP
server
server
server
server
server
server
vic
vic
vic
19
Chromium support for Reality Centre-type displays

• Issues
• Non-flat screen (spherical section)
• Multiple projectors (3 edge blending)
• Now using commodity data projectors
• No compensation in projectors
• Solution
• Determine required warping
• set-up application
• Render image, grab as texture, draw on distorted
  geometry with dark edges
• As a Chromium server-side SPU

20
Samples
21
Integrating the e-science-GS system

• Has optional Java3D interface
• Integrate with Java3D vic client
• Sample later this week?!

22
Conclusions future work

• ECT as alternative/enhanced local node management
  framework?
• More flexible 3D AG/VR client?
• Coordinated content
• As node service (tracking venue changes)
• Make code available to the community
• AG, Chromium