Recent years have witnessed an explosive growth in mobile video⁃based services and efficient and reliable video delivery draws more and more attention. As a type of rateless codes, fountain codes can automatically adapt to wireless channel conditions without any knowledge of channels. This paper provides an overview of several typical Forward Error Correction (FEC) codes, such as Reed⁃Solomon (RS) code, Tornado code, Luby⁃Transform (LT) code, and Raptor code. We focus on a novel delay⁃aware fountain coding (DAF) technique that maximizes the code word length under the constraint of a given delay. Based on DAF, this paper also presents Unequal Error Protection DAF (UEP⁃DAF) which improves the Peak Signal to Noise Ratio (PSNR) without additional coordination between the encoder and the decoder, as well as Model Predictive Control DAF (MPC⁃DAF) which reduces the computational complexity to an affordable level for real⁃time video communications. Moreover, we review video streaming technologies, then introduce Dynamic Adaptive Streaming over HTTP (DASH) and DASH over Multiple Content Distribution Servers (MCDS⁃DASH) in detail. Based on MCDS⁃DASH that adapts video bitrate at the block level to alleviate video fluctuation, we propose a novel approach to integrating fountain codes with MCDS⁃DASH, which is capable of achieving unprecedented high throughput.
mobile video delivery; DAF; UEP; MPC; DASH