Multimedia Web services for mobile clients using quality aware transcoding

Abstract

Mobile applications will increasingly depend upon multimedia information originating in the web and attempt to access this data over wireless networks that are more expensive and slower than typical wireline intemet access from desktops. Transcoding is an important technique that can allow network proxy servers to offer differentiated service by customizing the delivered object size for the network bandwidth available on the "last hop" to the mobile client. We exploit technology that we had previously developed that characterized the quality versus size tradeoffs in transcoding JPEG images. This technology supplies more information for use in transcoding policy decision making. We evaluate the performance benefits of incrementally incorporating this information in a series of transcoding policies.