Optimal Bandwidth Assignment for Multiple-Description-Coded Video

MPhil Thesis Defence


Title: "Optimal Bandwidth Assignment for Multiple-Description-Coded Video"

By

Mr. Pengye Xia


Abstract

In video streaming over multicast network, user bandwidth requirement is 
often heterogeneous possibly with orders of magnitude difference (say, 
from hundreds of kb/s for mobile devices to tens of Mb/s for high 
definition TV). Multiple description coding (MDC) can be used to address 
this bandwidth heterogeneity issue. In MDC, the video source is encoded 
into multiple independent descriptions. A receiver, depending on its 
available bandwidth, joins different descriptions to meet their bandwidth 
requirements. An important but challenging problem for MDC video multicast 
is how to assign bandwidth to each description in order to maximize 
overall user satisfaction. In this paper, we investigate this issue by 
formulating it as an optimization problem, with the objective to maximize 
user bandwidth experience by taking into account the encoding inefficiency 
due to MDC.

We prove that the optimization problem is in general NP-hard. However, if 
the description number is larger than or equal to a certain threshold (for 
a bandwidth heterogeneity of a factor of 100, such threshold is 7 
descriptions), there is an exact and simple solution to achieve maximum 
user satisfaction, i.e. meeting all the receiving bandwidth requirements. 
For the case when the description number is smaller, we present an 
efficient heuristic called SAMBA (Simulated Annealing for MDC Bandwidth 
Assignment) to assign bandwidth to each description given the distribution 
of user bandwidth requirement.

We evaluate our algorithm using simulations. SAMBA achieves virtually the 
same optimal performance based on exhaustive search. By comparing with 
other assignment algorithms, SAMBA significantly improves user 
satisfaction. We also show that, if the coding efficiency decreases with 
the number of descriptions, there is an optimal description number to 
achieve maximal user satisfaction.


Date:			Tuesday, 17 August 2010

Time:			3:00pm – 5:00pm

Venue:			Room 5486
 			Lifts 25/26

Committee Members:	Dr. Gary Chan (Supervisor)
 			Prof. Qian Zhang (Chairperson)
 			Dr. Lin Gu


**** ALL are Welcome ****