Grad makes online movie progress
By Amie Lynn Shirkie
Picture this predicament: You come home after a long day’s work for a quiet night of pay-per-view cinema. You make some popcorn, grab a pop, settle into your favorite easy chair, and turn on the television – only to find that the movie you want to watch doesn’t start for half an hour!
Fortunately, thanks to research conducted by recent U of S grad Anirban Mahanti, the waiting game may soon be over. Anirban has developed techniques allowing movies to be delivered on demand to several customers simultaneously over existing cable or satellite networks and the Internet – and all at low cost.
Anirban began his PhD in Computer Science at the U of S in 1999. Under the supervision of Prof. Derek Eager, he set out to find a solution to this pressing problem: “Think about the latest Bond movie. A digital copy is available on a media server, but if everyone in Saskatoon wants to watch this movie on demand, the cost of providing each request with a separate stream of media will be very high. How can you deliver video content on demand to a large number of users efficiently?”
In his research, Anirban made use of the multi-point delivery capability of modern communication networks, in which a server sends out one media stream, but multiple clients receive it. According to Anirban, using the Internet as a delivery medium presents several challenges, one of them being how to reliably deliver content to clients. “Services such as web browsers rely on retransmissions from the server to handle the loss of data packets in the network. However, this strategy doesn’t work well for on-demand video streaming, as it does not guarantee that data will be received in time to be played back.”
In order to counteract this difficulty, Anirban developed streaming protocols that efficiently enable data packet loss recovery. “We take a media file and divide it into segments. The segments are processed to generate a stream of unique packets. As long as you receive enough data packets to recreate the segment, you will be able to play it back.” According to Anirban, “In a way, the delivery of each segment resembles a water fountain.”
Delivering movies on demand isn’t the only use for Anirban’s research. Collaborating with researchers at the University of Wisconsin, he has developed a prototype system to provide online classes to students. He has also preformed some preliminary experiments using these techniques to deliver media via the internet between Saskatoon, Wisconsin and Calgary.
Anirban says he found his research topic “very interesting”: “It required a combination of analysis, simulation and experimentation.” He believes his research will be useful to various media delivery companies, including satellite providers, as well as the general public. “Entertainment is a major component of people’s lives. If people can receive high quality media when they want it, then I think that’s something they’ll appreciate.”
Anirban is also very pleased with the research opportunities provided by Eager. “Derek is an astounding researcher. He’s brilliant, meticulous, patient with his students, and always trying his to push his students to do better.” He rates his department highly as well: “The Department of Computer Science provided an excellent environment for cultivating my teaching skills. I got several teaching assistant assignments. Last summer, I also taught a second year course on Computer Architecture and Organization. The experience has been truly gratifying.” Anirban cites a family influence for sparking his interest in Computer Science. His father was a professor at the Birla Institute of Technology in India, and now holds a position in the Computer Science department at the University of New Brunswick. Anirban says he enjoys the cutting-edge, contemporary nature of his discipline and the many new opportunities for research and development it affords.
Anirban successfully defended his thesis in March. He is currently an Assistant Professor in the Department of Computer Science at the University of Calgary. He says he looks forward to supervising graduate students of his own in the near future.
Amie Lynn Shirkie writes graduate student profiles for the College of Graduate Studies & Research.