M. Conti et E. Gregori, Bandwidth allocation for the transmission of scalable MPEG video traffic with deterministic guarantees, REAL-TIME I, 7(3), 2001, pp. 237-253
This paper studies bandwidth allocation schemes for the transmission of VBR
video traffic with deterministic guarantees, i.e., no packets lossed and n
o missed deadlines. Specifically, we propose and investigate a policy named
quasi-constant policy. A VBR encoder attempts to keep the quality of video
output constant by varying the transmission rate (constant quality); on th
e other hand, with a quasi-constant policy the video quality transmission i
s reduced when congestion occurs. We assume that this reduction is obtained
by exploiting source scalability. By characterizing the traffic of a sourc
e with a constraint function, we define the relationship between the amount
of bandwidth assigned to a VER source and the maximum delay the applicatio
n may experience. By applying this relationship to long MPEG 2 traces (more
than one hour) we show that the quasi-constant policy is a very promising
direction for providing, in an efficient way, a deterministic QoS to VER vi
deo traffic. Specifically, the results presented indicate that with the qua
si-constant quality approach we can achieve a utilization greater than 50%
with a deadline of one second with only eight reduced-quality frames out of
1000. On the other hand, previous works ([1, 2]) indicate that with a cons
tant quality transmission, a 50% network utilization can be achieved only b
y tolerating a seven-second deadline. (C) 2001 Academic Press.