Comparison of Reed-Solomon and Raptor codes for the protection of video on-demand on the erasure channel

摘要

Streaming on-demand video services can be provided to an end user by transmitting video data as a sequence of Internet Protocol (IP) packets over the network. In order to maintain a sufficient video quality at the end user, video packets must be protected against erasures by means of a suitable form of error control. In this contribution we make a comparison of 2 classes of Forward Error Correction (FEC) codes: the Reed-Solomon (RS) codes and the Raptor codes. We present the decoding complexity analysis of these codes and compare their erasure decoding performance. For a given decoding complexity, the codewords of the Raptor code can be taken much longer than those of the RS code, because the decoding of the former code involves only XOR operations. For a performance target of less than one decoding error event in 4 hours, a video bitrate of 7.3 Mbit/s, a latency constraint of 10 seconds and a transmission overhead of 20%, equal erasure probabilities at the decoder input are allowed for the RS(254,212) code and for the Raptor code of size (8760,7300), whereas this RS code has a 12 times higher decoding complexity.