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Transcoding Standards Activities
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Transcoding Standards Activities

We are striving to make the IBM transcoding platform open and standards compliant .  Towards these ends, we are pursuing standardization efforts in MPEG-7, W3C and WAP Forum. 

MPEG-7 - MPEG-7 has the mission to define a standard multimedia content description interface for search and retrieval of multimedia.  Since enabling effective multimedia content access for a wide diversity of client devices is becoming one of the important emerging problems in the generation of pervasive computing, we have helped MPEG-7 to define the application called Universal Multimedia Access.  IBM trascoding researchers have developed the requirements for Universal Multimedia Access with a team composed of researchers from Ericsson, AT&T, Nokia, Columbia, EPFL and KRDL.

The IBM is proposing a number of specific multimedia content descriptors that will facilitate the adaptation of the multimedia content to pervasive devices.

We are receiving broad based support from both industrial and academic institutions on these initiatives.  If you are also interested joining the standardization efforts, please contact Dr. John R Smith.

W3C: Within the W3C, IBM has been a co-editor of the Composite Capability/Preference Profiles (CC/PP) specification, which defines a vocabulary and format for describing a web client's device hardware capabilities, software capabilities, user preferences, and network characteristics to transcoding proxies and content servers.  The CC/PP Exchange specification defines how these CC/PP descriptions can be transmitted over HTTP 1.1.  For more information about these activities, contact Dr. Sandeep Singhal (mailto:singhal@us.ibm.com)

Composite Capability/Preference Profile (CC/PP) is a collection of the capabilities and preferences associated with user and the agents used by the user to access the World Wide Web. These user agents include the hardware platform, system software and applications used by the user. User agent capabilities and references can be thought of as metadata or properties and descriptions of the user agent hardware and software.

A description of the user's capabilities and preferences is necessary but insufficient to provide a general content negotiation solution. A general framework for content negotiation requires a means for describing the meta data or attributes and preferences of the user and his/hers/its agents, the attributes of the content and the rules for adapting content to the capabilities and preferences of the user. The current mechanisms, such as accept headers and <alt> tags, are somewhat limited. Future services will be more demanding. For example: the content might be authored in multiple languages with different levels of confidence in the translation and the user might be able to understand multiple languages with different levels of proficiency. To complete the negotiation some rule is needed for selecting a version of the document based on weighing the user's proficiency in different languages against the quality of the documents various translations.

CC/PP exchange protocol based on HTTP Extension Framework: The CC/PP framework is a mechanism for describing the capabilities and preferences associated with users and user agents accessing the World Wide Web. Information about user agents includes the hardware platform, system software, applications and user preferences [P3P]. The user agent capabilities and preferences can be thought of as metadata, or properties and descriptions of the user agent's hardware and software. The CC/PP descriptions are intended to provide information necessary to adapt the content and the content delivery mechanisms to best fit the capabilities and preferences of the user and its agents.

The major disadvantage of this format is that it is verbose. Some networks are very slow and this would be a moderately expensive way to handle metadata. There are several optimizations possible to help deal with network performance issues. One strategy is to use a compressed form of XML [WBXML], and a complementary strategy is to use references(URIs).

Instead of enumerating each set of attributes, a reference can be used to name a collection of attributes such as the hardware platform defaults. This has the advantage of enabling the separate fetching and caching of functional subsets.

Another problem is to propogate changes to the current CC/PP descriptions to an origin server, a gateway or a proxy. One solution is to transmit the entire CC/PP descriptions with each change. This is not ideal for slow networks. An alternative is to send only the changes.

The CC/PP exchange protocol does not depend on the profile format which it conveys. Therefore another profile format besides the CC/PP description format could be applied to the CC/PP exchange protocol.

WAP Forum: Within the WAP Forum, IBM has been leading the effort to define the User Agent Profiles (UAProf) specification, which defines a concrete CC/PP vocabulary for mobile information appliances and defines an efficient transmission of these CC/PP descriptions over wireless networks.  For more information about this activity, contact Dr. Sandeep Singhal .