Hybrid digital-analog video multicast scheme based on H.264/AVC and SoftCast

Wireless video multicast has become one of the key technologies to wireless applications. But the main challenge of wireless video multicast, i.e. the “cliff effect”, remains to be solved. SoftCast is a novel video coding and transmission scheme which allocates power to different coefficient chunks and transmits analog signals directly without quantization and entropy coding. It can solve the “cliff effect” effectively. And when it sends one video to multiply receivers, all the receivers can decode video performances fit to their channel qualities. However, reconstruction performance of SoftCast is not good when it comes to some bad channels. In this paper, a hybrid digital-analog video multicast scheme which transmits the super-position signal of H.264/AVC stream and H.264/AVC quantization residuals is proposed. With effective power allocation algorithm and appropriate parameter settings, gains provided by residuals signal are maximized. Simulation shows that the proposed scheme can achieve high performance gains based on SoftCast analog transmission and power allocation, and it outperforms the other hybrid digital-analog video multicast schemes by more than 4dB, e.g. the WSVC scheme.