Image transcoding for wireless WWW access: The user perspective
Mobile devices/clients vary in their hardware and software resources such as screen size, color depth, effective bandwidth, processing power, and the ability to handle different data formats. This makes it difficult for servers to support a wide range of client variations. In our research, we introduce an image transcoding proxy server placed between the generic WWW servers and the heterogeneous mobile hosts. The selection of transcoding operations is based on the mobile device characteristics and can adapt to dynamically changing bandwidth on the proxy-client link. The policy decisions are used to select the most appropriate operations in order to achieve the smallest file size and acceptable image quality. More aggressive transcoding operations result in greater loss of image quality. Based on a user survey, we determined minimal acceptable thresholds for each transcoding operation. As our results show, these thresholds are dependent on the display quality of the user device.