Vinay.R Mar Networked Media Lab GIST Multi-site Visualization Sharing

Contents  Introduction  Approach to share visualization  Visualization sharing environment  Sharing scenarios  Proposed solution  Prototype implementation  Test evaluation  Conclusion and future work

Introduction  Visualization of massive, complex data over multi- display (aura, chromium)  Collaborative environment for visualization  SAGE (scalable adaptive graphics environment) Suitable for images and videos  CGLX (cluster graphics library) Suitable for graphics apps  SMeet (smart meeting space) Supports heterogeneous displays  Share visualization ?  Concurrent view of visualization

Concurrent view Node 3 Node 4 Node 1 Node 2

Approach to share visualization  Collaborative visualization abstraction  Classify deployment scenarios  Understand requirements  Architect solution in SMeet environment  Implement and test

Visualization sharing environment S a collaboration session NSNS set of participating nodes of a session S MSMS set of media sources of a session S DSDS set of display elements of a session S VSVS set of visual elements of a session S MnMn set of media sources of a node n ∈ N S MnmMnm a media source in M n DnDn set of display elements of a node n ∈ N S DndDnd a display element in D n VndVnd set of visual elements displayed on D n d V n d,v a visual element in V n d RndRnd whole screen of D n d R n d,v screen region of V n d,v R n d (x,y,w,h) rectangle region of D n d starting from (x,y) with a width (w) and a height (h)

Sharing scenarios  Single-session, Single-interest  Single-session, Multi-interest  Multi-session, Multi-interest

example  Single-session, Single-interest  Single-session, Multi-interest

Proposed Solution (high level view)  Add replication layer to replicate media contents to all the nodes

Proposed Solution (detailed view) Current SMOD structure

Proposed Solution (detailed view)  Modified SMOD structure  Multiple clustered displayers  Replication manager module  Display configuration module

Display resolution mapping Without mapping Simple mapping

Mapping algorithm 1. Find source to dest. total display resolution ratio 2. Calculate dest. VE’s origin point (bottom left) based on ratio 3. If source VE’s width is out of dest. display’s horizontal range 4. Then adjust dest. VE’s width to maximum 5. Else dest. VE’s width is equal to source VE’s width 6. If source VE’s height is out of dest. display’s vertical range 7. Then adjust dest. VE’s height to maximum 8. Else dest. VE’s height is equal to source VE’s height h_src h_dest y_src x_src v_src v_dest y_dest x_dest ht_src w_src ht_dest w_dest VE – visual element

Prototype Implementation  “Single session, Single interest” scenario is implemented for now.  Replication Manager written in C++

Testbed

Evaluation  Images ranging from 2 mega pixels to 35 mega pixels consume approximately 1 to 2 seconds  Images are shared only one time i.e. pixels are replicated only once  Video streams of resolution 1280x720 are captured at a frame rate of 30 fps.  Delay to replicate does not cross more than 90 milliseconds  No abrupt variations in network delay (frames are generated at a constant rate )

Related Work  SAGE Visualcasting  broadcasts media contents directly to all the end-point display nodes  Streaming-based VNC solution *  single-master multi- slave configuration (not useful for collaboration) * Zhongding Jiang et al., “A streaming-based approach for remote interaction of the multi-channel display system for group users,” Multimedia and Expo, 2008 IEEE International Conference on, vol., no., pp , 2008.

Conclusion  Approach to design a flexible multisite visualization sharing system  Described different scenarios in a visualization sharing environment  Visualization sharing system implemented on SMeet Future Work  Share selective region of tiled display area  Share interactions (keyboard, mouse, pointer)  Test with more than two nodes  Develop performance model