Adjustable Bandwidth DVTS for Heterogeneous Internet Environment Yasuo Tsuchimoto AIT / Keio / WIDE
Digital Video Communication DVTS can support communications Distance learning On-line meeting Observations Characteristic of DV stream Full NTSC/PAL quality video stream No special equipments are needed No encoding delay 30Mbps traffic
Heterogeneous Internet Environment Example)
Approach Encoding video? No! Encoding delay will be generated The video quality can be worse than original Receiver-driven Layered Multicast? Maybe yes… But jitter expected to become big Replacement of sender and receiver required
Approach (cont.) Reducing frame rate? Yes! Small frame rate is acceptable Small overhead Acceptable delay No need to touch sender and receiver User doesnt have to know about network
Design How can we reduce frame rate? The small box with frame thin-out function On the path from sender and receiver 30fps 10fps
DVTS repeater It has a function of both dvsend and dvrecv Thin-out module is added It can be cascaded narrower network can receive lower frame rate Named dvrelay
Basic idea: How to thin out One frame consist from many DIF blocks. IP packet carry 17 DIF blocks Audio Video and some info Focus on RTP timestamp It increases 3003 for every frame It can specify the frame dvrelay thin out only video Video DIF block will omitted Other block will be transferred
The design of Thin-out module
Implementation It is implemented on application layer Any kind of traffic can be thinned out Unicast – Unicast Multicast – Unicast Unicast – Multicast Multicast – Multicast Support both IPv4 and IPv6 Currently dvrelay can be run on Linux box
Test: dvrelay Sending Full DV stream from sender dvrelay thin-outs frames it change the frame rate from 30fps to 10fps Receiver receives 10fps DV stream
Result
Conclusion and future work dvrelay can reduce the traffic Bandwidth can be reduced by dvrelay Poor environment can receive DV stream Evaluations using AI3 Bandwidth Jitter Delay
Final goal of this project
Thank you, any questions?