2. A Survey of Packet Loss Recovery Techniques for Streaming Audio Colin Perkins, Orion Hodson, and Vicky Hardman University College London IEEE Network September/October 1998 Hung, Kuo-EnNTHU/CS, Visual Communication Lab.

3. Outline Observed Network Situations Sender-based repair –Forward error correction –Interleaving –Retransmission Receiver-based repair –Insertion-based repair –Interpolation-based repair –Regeneration-based repair Summary

4. Observed network situations

5. Observed network situations (Cont’d)

6. Sender-based repair

7. Media-Independent FEC Parity coding Reed-Solomon coding –Take a set of codewords and use these as coefficients of a polynomial, f(x). Disadvantages –Delay imposed –Increased bandwidth –Difficult decoder implementation

8. Parity coding

9. Media-Specific FEC

10. Interleaving

11. Retransmission End to end delays need to be less than 250 ms Used for scalable reliable multicast (SRM)

12. Receiver-based repair

13. Insertion-based repair Splicing Silence substitution Noise substitution Repetition

14. Interpolation-based repair Waveform substitution Pitch waveform replication Time scale modification

15. Regeneration-based repair Interpolation of transmitted state Model-based recovery

16. Summary Rough quality/complexity trade-off for error concealment Sample error concealment techniques

17. Rough quality/complexity trade-off for error concealment

18. Sample error concealment techniques