Adjustable Bandwidth DVTS for Heterogeneous Internet Environment

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Adjustable Bandwidth DVTS for Heterogeneous
Internet Environment

• Yasuo Tsuchimoto
• AIT / Keio / WIDE
• tsuchy_at_ait.ac.th

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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

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Heterogeneous Internet Environment

• Example)

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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

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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

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Design

• How can we reduce frame rate?
• The small box with frame thin-out function
• On the path from sender and receiver

30fps
30fps
10fps
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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

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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

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The design of Thin-out module
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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

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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

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Result
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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

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Final goal of this project
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Thank you, any questions?