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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)
13Mbps
FE GbE
FE
30MbpsATM
GbE
FE
11Mbps/ 54Mbps
Approach
Encoding video?No!Encoding delay will be generatedThe video quality can be worse than original
Receiver-driven Layered Multicast?Maybe yes…But jitter expected to become bigReplacement of sender and receiver required
Approach (cont.)
Reducing frame rate?Yes!Small frame rate is acceptableSmall overhead
Acceptable delayNo need to touch sender and receiverUser doesn’t 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
Sender
Repeater
Reciever
Reciever
30fps
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
DVTS repeater
dvsend dvrecv thin out dvsend dvrecv
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
IP
UDP
RTP
Payload
DIF:H
DIF:S
::
DIF:VA
DIF:A
DIF:V
DIF:H
DIF:S
DIF:VA
DIF:A
DIF:V
The design of Thin-out module
IP
UDP
RTP
PayloadDIF
DIF
DIF
DIF
::
H
S
VA
A
V
H
S
VA
A
V
H
S
H
S
VA
A
H
S
VA
A
H
S
H
S
VA
A
H
S
VA
A
H
S
DVTS repeaterDVTS sender DVTS reciever
V
30 fps 10 fps
Implementation
It is implemented on application layerAny 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
dvsend dvrelay dvrecv
30 fps 10 fps
203.159.31.97 203.159.31.98 203.159.31.62
Result
0
5
10
15
20
25
30
35
19:55:47 19:56:04 19:56:21 19:56:38 19:56:56 19:57:13 19:57:30
Transmission Rate (Mbps)
Time
dvsend
dvrecv
Conclusion and future work
dvrelay can reduce the trafficBandwidth can be reduced by dvrelayPoor environment can receive DV stream
Evaluations using AI3BandwidthJitterDelay
Final goal of this project
Internet
RENATOR
UPMC
WIDE
AI3
IPv6 over IPv4
AIT ITCUSS
Thank you, any questions?