This paper discusses issues related to the delivery of MPEG-4 video over the Internet and wireless channels. MPEG-4's built-in error resilience capabilities such as flexible re-synchronization markers, data partitioning, header protection, reversible VLCs, and forced intra-frame refresh are described. Methods for using these techniques to build a “smart” network decoder are discussed, and the decoder's video quality is measured for various channel error conditions. The effectiveness and overheads of the various error resilience techniques are compared using both peak signal-to-noise ratio measurements and expert viewing. The use of forward error correcting strategies and the effects of packet sizes and boundaries on video quality are also examined.