CAVE/RC-to-street

Access Grid Integration

Chris Greenhalgh

University of Nottingham

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

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

What is the Access Grid: in use

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

How is the Access Grid (v.2.3) implemented?

VirtualVenue

Venue Server

ServiceManager:Vic (video)

ServiceManager:

Rat (audio)

Node manager

Venueclient

VenueEventbus

SharedApp n

Local App n

VenueData n

UserData n

CamerasVideo windows

Micsspeakers

Joining a venue

VirtualVenue

Venue Server

ServiceManager:Vic (video)

ServiceManager:

Rat (audio)

Node manager

Venueclient

VenueEventbus

SharedApp n

Local App n

VenueData n

UserData n

CamerasVideo windows

Micsspeakers

1. Join

2. Streams

3. Exec rat 3. Exec vic

Running a shared application

VirtualVenue

Venue Server

ServiceManager:Vic (video)

ServiceManager:

Rat (audio)

Node manager

Venueclient

VenueEventbus

SharedApp n

Local App n

VenueData n

UserData n

CamerasVideo windows

Micsspeakers

1. Get info (Join)

2. start

3. get/set state

4.events

Sharing data

VirtualVenue

Venue Server

ServiceManager:Vic (video)

ServiceManager:

Rat (audio)

Node manager

Venueclient

VenueEventbus

SharedApp n

Local App n

VenueData n

UserData n

CamerasVideo windows

Micsspeakers

1. Get info (Join) / Save data2. Get data

1. create/2. get

3. start

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

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

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]

Integration Options (4)

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

• [done]

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

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…

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

Chromium distribution issues

application vic

chromium

server server server

Textures over TCP

application vic

chromium

server server server

OnlyStream IDs over TCP

video

video

vic vic vic

Standard With video texture SPU

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

Samples…

Integrating the e-science-GS system

• Has optional Java3D interface

• Integrate with Java3D vic client

• Sample… [later this week?!]

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