Error Robust Coding for the FGS Enhancement Bitstream

Fine Granularity Scalable (FGS) video coding scheme provides a layered bitstream structure with different importance at different layers. This property makes FGS bitstream more suitable for transmission over the error-prone channels with unequal error protection schemes. Even though the hierarchical FGS enhancement bitstream can always resynchronize in the next video packet when there are transmission errors, each error will still cause a large amount of received enhancement bits undecodable due to the dependency among enhancement layers. In this paper, we first propose to use the Universal VLC (UVLC) technique to further limit the effects of transmission errors to within one or only a few blocks by taking advantage of the excellent self-synchronization property of the UVLC. Furthermore, the higher priority data of Coded Bit Pattern (CBP) is separated from the DCT data in the same video packet and put in the beginning of each video packet to avoid the error impact from the DCT coefficients. The experimental results show that the FGS enhancement bitstream with the proposed coding techniques has greater capability in locating and isolating errors and resynchronization. The decodable bits of FGS enhancement layer increase significantly while the bit rate increases. Meanwhile, the decoded video quality can be improved up to 0.8dB in PSNR.