Distributed Realcast: A Channel-Adaptive Video Broadcast Delivery Scheme

The performance of the mobile video broadcast is weakened when applying the traditional broadcast scheme which is forced to pick a single bit rate supported by the worst receiver. It leads to the drawback that receivers with better channels cannot obtain better video qualities. This paper proposed distributed Realcast, an analog video delivery scheme based on real value transmission, to provide differentiated video service. It utilizes a series of linear operations to encode video without digital processing so that the channel noise is proportional to the distortion in video pixels and achieve channel adaptive transmission. Meanwhile, a distributed video coding scheme combining the frame difference method and the coset coding is proposed to realize the efficient video compression and prevent error propagation. In addition, distributed Realcast performs the motion compensated extrapolation method at both the encoder and decoder to avoid the transmission of motion vectors and release the stress of limited bandwidth. Simulation results indicate that distributed realcast outperforms Softcast, a representative analog video broadcast scheme, by nearly 3db.