(Portions reprinted, with permission, from M. Naccari, G. Bressan, M. Tagliasacchi, F. Pereira, S. Tubaro, “Unequal error protection based on flexible macroblock ordering for robust H.264/AVC video transcoding”, Picture Coding Symposium, Lisbon, November 2007. ©2007 EURASIP.)
The techniques described in this chapter correspond to the non-normative areas of video coding standards. They deal with error resilience and rate control, and can readily be applied to existing codecs without compromising standard compatibility, since they work within the realm of the standard. While the objective of error-resilience techniques is to improve the performance of the video coding system in the presence of channel errors, rate control techniques improve performance by adequately distributing the available bit-rate resources in space and time. Research in the field of non-normative video coding tools up till now has shown how important these tools are in getting the best performance from normative video coding standards. The non-normative video coding tools are the “decision makers” that any video coding standard needs in order to find the “right path” through a flexible coding syntax, for example in the most powerful coding standards like MPEG-4 Visual and H.264/AVC.