Error Resilience Methods for FGS Video Enhancement Bitstream
Fine Granularity Scalable (FGS) video coding scheme that has been recently adopted in the MPEG-4 streaming video profile provides a layered and fine granularity scalable bitstream with different importance at different layers. This property makes FGS bitstream suitable for transmitting over the error-prone channels with unequal error protection. However, there are no tools currently available for error resilience in the FGS enhancement bitstream. This causes two problems when delivering the enhancement bitstream through an error-prone channel. First, there is only a weak error detection capability in the enhancement layer. The decoder would put a lot of wrong data into the decoded video before it knows an error has occured in the bitstream. Secondly, in the current FGS scheme, once the decoder detects an error, it would discard the rest of the bitstream in that frame. The effective transmitted video data will be determined by the channel error rate, but not by the channel bandwidth. In this paper, we propose to include some error-resilience tools into the FGS enhancement layer bitstream. We design a hierarchical enhancement layer bitstream structure with resynchronization markers and Header Extension Code (HEC). The experimental results show that the proposed enhancement layer bitstream has stronger error detection and resynchronization capabilities when transmitted over error-prone channels. Thus it provides much better decoded video.