Visual Media Coding and Transmission

11.3 Other Standardization Efforts by the IETF and W3C

In addition to the tools and descriptions specified in MPEG-21, other standardization bodies have also conducted work towards the support of context-aware applications and the assistance of adaptation operations. Such standardization organizations include the W3C and the Internet Engineering Task Force (IETF), both of which have delivered related specifications for a few recent years.

Content adaptation at the network edges is already being performed by content distributed mediators in order to balance the network load or in an attempt to satisfy different user groups' profiles and redirect requests based on geography and/or other profile characteristics. This is being achieved through the use of content distribution networks (CDNs), peer-to-peer (P2P) technologies, and personalization techniques [34].

In the mobile networking world, content filtering services are being added to most caches. Wireless network proxies transform both protocol and Web content, converting HyperText Markup Language (HTML) into Website Meta Language (WML) for small-screen displays and HyperText Transfer Protocol (HTTP) into Wireless Datagram Protocol (WDP) for wireless delivery purposes. Adaptation of content, aiming at increased penetration, is already happening, in particular in the mobile world. However, it still offers somewhat limited functionality, as it essentially accounts for bandwidth restrictions and limited device capabilities. The focus ...