A Rateless UEP Convolutional Code for Robust SVC/MGS Wireless Broadcasting

Wireless broadcasting of scalable video coded medium grain scalable (SVC/MGS) bit streams requires unequal erasure protection (UEP) at the transport layer in order to ensure graceful degradation of playback video quality over a wide range of frame error rates. Modern wireless broadcasting systems even employ rate less fountain codes to aid the receivers in making inevitable tradeoffs among picture quality, channel throughput and playback latency. Designing a rate less UEP channel code fits for such an application posts distinct engineering challenges as the necessary protection for SVC base and enhancement layers differ by orders of magnitude while their intradependent groups of pictures fluctuate notably in their sizes. In this paper, we present the design and implementation of a rate less UEP convolutional code that meets these demanding requirements. Use of this UEP channel code along with rate-distortion based network application layer unit extraction offer sufficient protection to SVC bit streams under different lossy conditions without the need to re-code the bit stream. We also investigated the differences in playback performance of SVC bit streams that were protected by rate less codes vs. conventional Reed-Solomon codes. The comparison makes clear the advantages and the disadvantages of employing rate less codes in protecting wireless video broad-casting.