PostScript (83 KB)Meeting Arbitrary QoS Constraints Using
Dynamic Rate Shaping of Coded Digital Video
Proceedings, 5th International Workshop on Network and Operating System
Support for Digital Audio and Video, Durham, New Hampshire, April 1995,
pp. 95-106
Reprinted in "Lecture Notes in Computer Science Series," Vol. 1018,
Springer-Verlag, 1995.
Abstract
We introduce the concept Dynamic Rate Shaping, a technique to adapt the rate of compressed video bitstreams (MPEG-1, MPEG-2, H.261, as well as JPEG) to dynamically varying rate (and delay) constraints. The approach provides an interface (or filter) between the encoder and the network, with which the encoder's output can be perfectly matched to the network's quality of service characteristics (if any). Since the presented algorithms do not require interaction with the encoder, they are fully applicable to precoded, stored video (as in, for example, video-on-demand systems). By providing decoupling of the encoder and the network, universal interoperability can be achieved. A set of low-complexity algorithms for dynamic rate shaping is presented, and both optimal and extremely fast (but slightly suboptimal) designs are discussed. The latter are simple enough to allow software-based implementation. Experimental results are provided using actual MPEG-2 bitstreams.