Scalable multimedia bitstreams are very sensitive to packet losses and bit errors in transmission channels, and therefore robust error protection is needed. FEC-based error protection algorithms are discussed in this paper. The key objective of these algorithms is to reasonably allocate bits between source coding and channel coding so that the reconstruction signal quality seen at the decoder side can be optimized. According to error statistics, transmission channels are classified into two models: packet-loss channel and wireless bit-error channel. A uniform problem description is formulated for each model's error protection scheme and optimization objective. Major algorithms in the literature are surveyed and their performance and complexities are analyzed. Finally, future directions are discussed.