IEC 62261-1-2005 pdf – Television METADATA – Part 1: Metadata dictionary structure

IEC 62261-1-2005 pdf – Television METADATA – Part 1: Metadata dictionary structure.
1 Scope The metadata dictionary structure defined in this part of IEC 62261 covers the use of metadata for all types of essence (video, audio, and data in their various forms). Applications of individual dictionary entries will vary but, when used, metadata shall conform to the definitions and formats in this metadata dictionary structure standard and the associated metadata dictionary recommended practice (IEC 62261-3). IEC 62261-3 defines a registered set of metadata element descriptions for association with essence or other metadata and this standard and the contents practice shall be used together as a pair – neither shall be used in isolation. The IEC may, from time to time, appoint other bodies to act as its Registration Authority and Agent for the compilation and safe keeping of IEC 62261-3 as described in IEC 62261-2. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 62261-2, Television metadata – Part 2: Data encoding protocol using key-length-value IEC 62261-3, Television metadata – Part 3: Universal labels for unique identification of digital data 3 Metadata dictionary structure 3.1 General The metadata dictionary structure provides flexibility in capturing metadata and exchanging it among applications through a standardized hierarchy of universal labels for the metadata elements, grouped to aid their management within a small but comprehensive number of classes. Metadata classes are collections of metadata elements with common characteristics or attributes. Additional classes are provided for user-defined metadata.
IEC 62261-3 references an individual item or element of metadata using a two-part 16-byte universal label that is numerical (and hence language-independent) and unique. The first eight bytes label the second eight bytes as a “tag” in a specific version of a designated metadata dictionary (“tags” are defined in IEC 62261-2 (key-length-value encoding)). This tag is used to index the meaning or definition of the metadata element. The actual metadata information described by the metadata element is the metadata value. The dictionary also contains information on the required format of metadata values and the allowable range of values (if applicable) either as a list or as a bounded range. Individual data element values can frequently be represented in more than one way – for instance, it is possible to represent a textual value as ASCII or unicode, where the value is identical but the particular representation different. It is important both that the representation is known and that as new representations are registered they can be accommodated. In this case, the last active word of the tag defines the representation in use – the default being 00 h
The metadata dictionary is organized into nodes and leaves. The dictionary classes just described form class nodes and below these are further nodes at each subclass. To aid the management of the dictionary, these nodes and subnodes are assigned tags to which no value is assigned, so as to give clear breaks in the structure. Entries within a subclass form leaves, which are the data elements themselves. Lower levels of the dictionary structure can be derived from the tag structure in IEC 62261-3. 3.2 Compatibility with other metadata structures The metadata dictionary structure is a framework that supports global interoperability by defining metadata tags in a way that enables the interchange of IEC metadata with metadata from different sources and originated by other bodies. Many different cataloguing conventions are used by communities who focus on a specific domain or subject or who have specific needs for archive and retrieval of multimedia data including, for example, intellectual rights. The metadata dictionary is not intended to replace conventions already in use, for example, in textual naming or keywords. Within the framework of the metadata dictionary structure, different content creation communities, media indexing professionals, or metadata extractors and users can develop metadata conventions that meet their specific requirements. 3.3 Individual metadata classes 3.3.1 Organization Within the metadata dictionary, metadata elements are organized into a hierarchical structure, where each is assigned to a metadata class as shown in the overview of Figure 1. The initial set of metadata classes in this standard consists of Class 1: Identification and location Class 2: Administration Class 3: Interpretive Class 4: Parametric Class 5: Process Class 6: Relational Class 7: Spatio-temporal Class 15: Experimental The number of metadata classes can be extended in the future to a maximum of 127.