Effects of channel delays on underflow events of compressed video over the Internet
Dmitri Loguinov, Hayder Radha · Proceedings - International Conference on Image Processing · 2003
This paper presents an extensive statistical study and analysis of the effects of channel delays in the current (best-effort) Internet on underflow events in MPEG-4 video streaming. Two types of network delays are considered: end-to-end round-trip delays and delay jitter. Our data were collected in a seven-month real-time streaming experiment, which was conducted between a number of unicast dialup clients in more than 600 major USA cities and a backbone video server. Among other findings, our analysis shows that startup delays approximately 15-20 times the average roundtrip time (RTT) are required for the client to avoid 90% of late packets caused by delay jitter. Meanwhile, startup delays of only 3-4 times the average RTT are needed to achieve lost-packet recovery rates of 90% or more. Hence, a key finding of our study is that delay jitter represents a more challenging problem for video streaming applications than round-trip delays. We also show that the probability density function (PDF) of RTT samples, which are associated with retransmitted video packets, can be modeled using a Pareto distribution. This observation indicates that the upper tail of the RTT PDF decays slower than reported in earlier studies.