XML Specification
<complexType name="EventInformationType"> <sequence> <element name="PublishedTime" type="dateTime" minOccurs="0"/> <element name="PublishedDuration" type="duration" minOccurs="0"/> <element name="Live" type="tva:FlagType" minOccurs="0"/> <element name="Repeat" type="tva:FlagType" minOccurs="0"/> <element name="FirstShowing" type="tva:FlagType" minOccurs="0"/> <element name="LastShowing" type="tva:FlagType" minOccurs="0"/> <element name="Free" type="tva:FlagType" minOccurs="0"/> </sequence>
From TV-Anytime Metadata Specification Version 1.2, WD498 Part-A.doc in ftp://tva:tva@ftp.bbc.co.uk/pub/Plenary/TV096r2.zip
Notes:
This describes a broadcast "event" (TV program), including the time at which the program is advertised as starting, duration, if it is a live broadcast or repeat and if the program is free.The Metadata working group released a first requirements document in April 2000.
Documents are publicly available from the forum web site, as zipped MS-Word documents. As with MHP and TeleWeb, this makes the standards difficult to find, download and read (Worthington 2002). In contrast Internet and web standards are provided in an easy-to-use text and web formats.
TV-Anytime uses XML syntax for defining what metadata will be used (the schema) and then to actually encode the actual data (instances). The metadata structure is defined using the XML Schema based MPEG-7 Description Definition Language (ISO 2001). XML Schema is a recent web standard for defining sophisticated data structures (Worthington 2001b), which uses the XML syntax.
While XML has advantages, being widely supported and easy to generate, it is a verbose text format. TV-Anytime propose using binary encoding and compression of the XML for efficiency. However, the draft documents contain notes indicating that there is some disagreement as to the format. It might be simpler if plain text was initially used and compression added as an option, if needed later. Given that metadata would represent a small amount information, compared to video data, the complexity of compression may not be worthwhile.