MULTIRESOLUTION LAYERED CODING FOR REAL-TIME IMAGE TRANSMISSION - ARCHITECTURAL AND ERROR CONTROL CONSIDERATIONS

We examine the rationale for and systems aspects of using layered codi ng for the transmission of images and video over heterogeneous communi cation networks. We advocate multi-resolution layered coding (MLC) and present architectural alternatives that can support it within the sco pe of existing standards and technologies. Since the premise of layere d coding is controlled loss, the issues of error control and concealme nt are central. We demonstrate that MLC exhibits good error tolerance, effectively compensating for errors in situations where traditional e rror concealment schemes, based on the interpolation of pixels in adja cent blocks, are ineffective. In particular, MLC yields a higher peak signal-to-noise ratio (PSNR) than two-layer coding when packet loss oc curs in the base layer. Finally, we show that MLC can effectively expl oit efficient network error control strategies which distribute redund ancy non-uniformly and provide unequal levels of protection across lay ers. (C) 1998 Academic Press.