Scalable Video Coding with Digital Fountain

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Scalable Video Coding with Digital Fountain

• Kai-Chao Yang

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Digital Fountain (DF)

• Distribute or duplicate k source packets into
  k(1?) packets.
• Original data can be reconstructed as long as
  enough packets are received at the client. -
  Retransmission-free

Server
Client
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Digital Fountain (DF)

• Examples of DF codes
• Reed-Solomon codes (RS codes)
• Luby Transform codes (LT codes)

y1
y1
Original packets
Encoded packets
x1
x1
y2
y1 x1?x2
x2
x2
y3
x1
Receive any three packets to reconstruct original
data
y3
y2 x1
x3
x3
y4
x2
y3 x2?x3
y1
x3
y4 x3
x1
x1
y2
y2
x2
x2
Distribution D
y3
x3
x3
y4
y4
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Digital Fountain (DF)

• Products
• NTT ST1000/2000 IP-STB
• DF FEC codes (Using LT codes)

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Scalable Video Coding with DF

• Objective
• Video downloading The quality of videos depends
  on downloading time.
• Video streaming FGS-like coding.
• Feature Different source packets have different
  degree of importance.
• Idea Let important packets can be more easily
  reconstructed.
• When downloading, important data are firstly
  reconstructed.
• Method Data partitioning LT codes
• Data partitioning in H.264/AVC
• Type A, B, and C partitions
• Importance A gtB gt C
• Size A lt B lt C

x1
A
x1
x1? x2
x2
x1? x3
B
x3
x1? x4
x4
x1? x5
x5
x1? x6
C
x6
x1? x7
x7
x2
x3
x4
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Scalable Video Coding with DF


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Scalable Video Coding with DF

• Simulation results
• 2000 source packets to 2080 DF packets
• Type A 10
• Type B 70
• Type C 1920
• More efficiently
• coding structure?

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Layered DF Coding
Importance
Loss rate
recovery rate
Layer N2
Layer N1
Layer N