Implementation of Video Layering in Multicast Transmission

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Implementation of Video Layering in Multicast
Transmission

• L. Suniga, I Tabios, J. Ibabao
• Computer Networks Laboratory
  University of the Philippines

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Problem
100 Mbps
10 Mbps
10 Mbps
100 Mbps

• How to deliver scalable multicast video over
  networks with varying bandwidth constraints
  without compromising quality?

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Problem

• Congestion on the slow links
• Limit data to fit slowest link
• ? everybody suffers
• Encode and send different files depending on
  connection speed
• processor intensive
• user must know link speed

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Solution
100 Mbps
10 Mbps
10 Mbps
100 Mbps

• Split video information over a number of layers
  and have clients receive only the layers they need

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How do you layer video?

• Use wavelet coding scheme
• Multi-resolution analysis time scale
  representation of a signal using digital
  filtering techniques
• Discrete Wavelet Transform (DWT)
• Decompose the signal to its course approximation
  and its detailed approximation
• Half-band filters

Upsampling / Downsampling
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Discrete Wavelet Transform
High-pass filter
Low-pass filter
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Software Design
Server-side module
Client-side module
VB6, OpenGL
Client Interface Module
Video Compression Module
Video Decompression Module
C/C
Transport Module
Rate Control Module
C/C
Multicast Network
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Server Compression Module
Get each frame
Raw AVI DIB File Format
Convert RGB frame to 422 YCrCb Frame
For each coeff
Build Huffman tree code table
Put result to DWT file
5-level FDWT, quantization thresholding
Perform Huffman compression
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Server Transport
Join base multicast group
Any client?
None
At least one
Send code table
Send base layer
L1 request?
Open layer 1 multicast address send layer 1
coefficients
L2 request?
Open layer 2 multicast address send layer 2
coefficients
L3 request?
Open layer 3 multicast address send layer 3
coefficients
Open layer 4multicast address send layer
4coefficients
L4 request?
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Client Side
Join base multicast group connect to server
Rebuild Huffman tree
Receive code table
IDWT
YUV-to-RGB
Receive base layer
Add new layer
Yes, probe failed
Congestion?
Drop new layer
None, probe succesful
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Testing
Client1
Client2
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Results
Layer 4
Layer 3
Layer 2
Layer 1
Base
Time (sec)
10
Client1 (10 Mbps)
Client2 (100 Mbps)
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Problems Encountered

• Asymmetrical system
• Off-line compression, real-time decompression
• Slow display ?graphics card processor specific
• Live testing with more clients
• Not that easy to implement multi-threading

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Recommendations

• Develop a faster codec to enable smoother
  playback
• Perform inter-frame techniques to achieve better
  compression
• Experiment on the optimum probe window length
  (dynamic or fixed?)

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Thank you!

• Robe Polikars Wavelet Tutorial
  http//engineering.rowan.edu/7polikar/wavelets/Wt
  utorial.html
• www.upd.edu.ph/cnl/
• jhoanna_at_eee.upd.edu.ph
• Based on the paper Highly-Scalable Wavelet-Base
  Video Codec for Low Bit Rate Environment Tham,
  Ranganath, Kassim. IEEE Journal on Selected Areas
  in Communications, January 1998.