Unequal error protection (UEP) for transmitting scalable image and video bit streams over packet erasure networks has been extensively studied. Most of the existing works consider UEP for a single source bitstream with chain-structure dependencies. However, in some state-of-the-art image and video coding techniques, such as MPEG-4 fine-grained scalable (FGS), there exist more complex tree-structure dependencies. In this paper, we propose a packetization framework for tree-structured bitstream, and present two rate allocation algorithms. Using MPEG-4 FGS as the source encoder, our experimental results show that the performance in terms of mean PSNR can be improved by adaptively allocating available bandwidth to different frames.
