Multi-resolution Layered Coding for Real-Time Image Transmission: Architectural and Error Control Considerations

We examine the rationale for and systems as pects of using layered coding for the transmission of im ages and video over heterogeneous communicationnetworks We advocate Multi resolution Layered Coding MLC and present architectural alternatives that can support it within the scope of existing standards and technologies Since the premise of layered coding is controlled loss the issues of er ror control and concealment are central We demonstrate that MLC exhibits good error tolerance e ectively compen sating for errors in situations where traditional error con cealment schemes based on the interpolation of pixels in adjacent blocks are ine ective In particular MLC yields a higher Peak Signal to Noise Ratio PSNR than two layer coding when packet loss occurs in the base layer Finally we show that MLC can e ectively exploit e cient network error control strategies which distribute redundancy non uniformly and provide unequal levels of protection across layers