ISO/IEC DIS 21000-22

Description / Abstract: The scope of MPEG-21 UD can be exemplified by the following use scenario. A Smart TV manufacturer has included a new type of recommendation functionalities in the TV set to help customers select programmes. The TV set supports standard User Description (UD), Context Description (CD) and Service Description (SD). With these data User can access different Recommendation Services each of which provides a standard Recommendation Description (RD). The TV set has an application, which mashes up the different recommendations and provides customized recommendations to User.

Therefore MPEG-21 UD standardizes the four data formats represented in Figure 1: User Description (UD), Context Description (CD), Service Description (SD), and Recommendation Description (RD).

• User Description (UD): a set of descriptions which may contain static and dynamic information about the user, including some other data like the history of the user's interactions, preferences, security settings regarding these information, etc.
• Context Description (CD): a set of descriptions of the environmental situation in which the user operates, e.g., user's device in use, physical position, environmental variables (temperature, humidity, sound level, etc.), security settings regarding these information, etc.
• Service Description (SD): a set of descriptions containing information (including security settings) about the service (or a set of sub-services), that is offered to the end-user application, e.g. video on demand, maps, etc.
• Recommendation Description (RD): a set of descriptions containing information about recommended items, provided when a customer requests a service in a certain context and in a certain environment. RD may include 1) the recommended content, 2) information extracted from UD, CD, SD; 3) additional logical relations among UD/CD/SD (or their subsets) and 4) metadata from UD/CD/SD.

The Description Managers of figure 1 are in charge of

1. Updating UD, CD and SD e.g. as a result of a User selection

2. Providing UD, CD and SD in response to requests coming from the Recommendation Engine.

This standard specifies User Description, Context Description, Service Description and Recommendation Description (in red in the figure). Description Managers, Recommendation Engine and Application (in black in the figure) are outside of the scope of this specification.