1. 1 Scalable Video Coding with Digital Fountain Kai-Chao Yang

2. 2 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 x1x1 x2x2 x3x3 x4x4 x5x5 x6x6 y1y1 y2y2 y3y3 y4y4 ynyn y2y2 y5y5 y9y9 y3y3 y8y8 y6y6 … x1x1 x2x2 x3x3 x4x4 x5x5 x6x6 Networks encode decode ServerClient

3. 3 Digital Fountain (DF) Examples of DF codes Reed-Solomon codes (RS codes) Luby Transform codes (LT codes) x1x1 x2x2 x3x3 x1x1 x2x2 x3x3 x1x1 x2x2 x3x3 x1x1 x2x2 x3x3 y3y3 y2y2 y1y1 y4y4 y2y2 y1y1 y4y4 y3y3 y1y1 y4y4 y2y2 y3y3 x1x1 x2x2 x3x3 y 1 = x 1  x 2 y 2 = x 1 y 3 = x 2  x 3 y 4 = x 3 Distribution: D Receive any three packets to reconstruct original data Original packets Encoded packets

4. 4 Digital Fountain (DF) Products NTT ST1000/2000 IP-STB DF FEC codes (Using LT codes)

5. 5 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 >B > C Size: A < B < C x1x1 x2x2 x4x4 x3x3 x5x5 x7x7 x6x6 A B C x1x1 x1 x2x1 x2 x1 x3x1 x3 x1 x4x1 x4 x1 x5x1 x5 x1 x6x1 x6 x1 x7x1 x7 x2x2 x3x3 x4x4

6. 6 A B C …… … …… A B C …… … …… … … Scalable Video Coding with DF

7. 7 Simulation results 2000 source packets to 2080 DF packets Type A: 10 Type B: 70 Type C: 1920 More efficiently coding structure? Failed decoding rate 00.5 Total packet loss rate Type A Type B Type C

8. 8 1 Mb/s 512 Kb/s 256 Kb/s Base Enhancement 1 Enhancement 2 Base Enhancement 1 Enhancement 2 Base Enhancement 1 Enhancement 2

9. 9 Layered DF Coding ImportanceLoss rate … … … … … Layer N Layer N+1 Layer N+2 recovery rate