Wei Tsang Ooi

Associate Professor
Department of Computer Science
National University of Singapore

research interest

Multimedia Systems / Networking / Interaction

I belong to NEMESYS, a research group focusing on interactive networked multimedia systems. Current topics of research include 3D streaming, interactive video streaming, networked virtual environments.

I am leading the Jiku project, under the NExT Search Center.

I am part of IPAL, a joint lab between NUS, I2R, CNRS (France), and UJF (France); and am affiliated with IDMI, the Interactive and Digital Media Institute of NUS.

recent papers

Supporting Zoomable Video Streams via Dynamic Region-of-Interest Cropping

with Ngo Quang Minh Khiem, Ravindra Guntur, Axel Carlier, MMSYS 2010, [PDF]

Streaming of an arbitrary region of interest (RoI) from a high resolution video is essential to supporting zooming and panning within a video stream. This paper explores two methods for RoI-based streaming, referring to them as tiled streaming and monolithic streaming. Tiled streaming parti- tions video frames into grid of tiles and encodes each tile as an independently decodable stream. Monolithic streaming applies to video encoded using off-the-shelf encoder, and re- lies on a pre-computed dependency information to send the necessary bits for the RoI. We evaluated these two methods in terms of bandwidth efficiency, storage requirement, and computational costs under different video encoding parame- ters. Experimental results show that bandwidth efficiency of tiled streams for RoI-based streaming reduces when tile size increases, despite improvement in compression efficiency. In the case of monolithic streams, use of a larger motion vec- tor range coupled with careful run-time optimization can still improve the bandwidth efficiency, despite an increase in motion vector dependency.

more publications..

recent courses

Introduction to Computer Networking

CS2105 is an introductory course on computer networking, where we take a tour through the five layers on Internet, discovering the various basic concepts and principles of Internetworking.

I have previously taught CS4344 Networked and Mobile Gaming, an advanced course on networking and systems support for multi-player games, CS5229 Advanced Computer Networks, a graduate-level course where we look into classic papers on the Internet, and CS2106 an introductory undergraduate course on operating systems.

recent talks

The Computer Science Behind YouTube

A talk given for Computing Outreach Programme, Hwa Chong Institution, April 2010. You can download the slides as PDF or view it via slideshare.

more talks..

Current TPC Memberships

MMSYS '13, MM '13, ICME '13

Guest Editorship


Springer's Multimedia Systems Journal (MMSJ) Special Issue on Network and Systems Support for Games

more services..



I received my B. Sc. (Hon.) degree from the Department of Information Systems and Computer Science (now School of Computing), NUS in 1996, and Ph. D. from Cornell University, Ithaca, NY in 2001. I spent a year as postdoc at Berkeley Multimedia Research Center in U.C. Berkeley, before re-joining NUS in 2002. I was originally from Alor Setar, Malaysia.

View C.V. in PDF format (last updated: December 2014)


AS6, #05-14,
Department of Computer Science,
National University of Singapore,
Singapore 117417.


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