Media Identification
by: Lawrence Harte

Digital media content must be uniquely identified. Some of the common identification codes that may be assigned to digital media include ISBN (books), ISSN (magazines), DOI (multimedia) and watermarks.

Unique Material Identifier (UMID)

A unique material identifier is a unique code that is used to identify audio-visual (AV) materials. The UMID standard was adopted as SMPTE standard 330M. The basic UMID contains 32 bytes of information and the first 12 bytes are used as a label to indicate that the media has a UMID code. Bytes 13 through 15 define the length of the material and the last 16 bytes of the UMID are a unique number that identifies the specific content item. 

A UMID can be extended with another 32 bytes of content descriptive information to create an extended UMID (EUMID). The EUMID contains the date, time and location where the content originated.

Figure 1.10 shows the structure of a EUMID identifier. This diagram shows that an EUMID is composed of the basic 32 byte UMID that contains the media identification information plus additional 32 bytes of descriptive information. This additional descriptive information includes the data and time the media was created, the place (location) that the media was created along with some additional user information.

International Standard Book Number (ISBN)

An international standard book number is a unique number assigned to a specific book. The ISBN identifies the issuing group, language or geographic area, publisher, title identifier and a calculated check digit to ensure an ISBN has been entered correctly into a computer or system.

An international standard serial number is a unique number that identifies the particular issue of a series of magazines or periodical publications. The ISSN number contains a unique portion that identifies the particular series of publication and a check digit to ensure an ISBN has been entered correctly into a computer or system. While the series publication is identified by the ISSN, the particular issue (e.g. volume or issue) of that series is defined by the publisher and it is not part of the ISSN.

Digital Object Identifier (DOI)

A digital object identifier is a unique number that can be used to identify any type or portion of content. DOI numbers perform for long term (persistent) and locatable (actionable) identification information for specific content or elements of content. This content can be in the form of bar codes (price codes), book or magazine identification numbers or software programs. The DOI system is managed by the International DOI foundation (IDF) that was established in 1998. More information about DOI numbering can be found at www.DOI.org.

DOI numbers point to a DOI directory which is linked to specific information about a particular object or its information elements. The use of a DOI directory as a locating mechanism allows for the redirecting of information about identification information as changes occur in its identifying characteristics. For example, a book identification number may belong to the original publisher until the copyright 

The numbering structure (syntax) for a DOI includes a directory and owner part (prefix) and unique item identification number (suffix). The prefix allows the DOI directory to redirect (DOI resolution) identification information to the owner or controller of the identifiable item. This redirection may be to a URL web link.
While it is important that there be only one DOI assigned per content object, a single object may have different types of identification numbers assigned to it. For example, a book can have a DOI, international standard book number (ISBN) and a manufacturers product number assigned to it.

Figure 1.11 shows digital object identifier (DOI) structure. This example shows that a DOI number is composed of a prefix that is assigned by the registration agency (RA) of the international DOI foundation and suffix that is assigned by the publisher of the content. This example shows that the first part of the prefix identifies the DOI directory that will be used and the second part identifies the publisher of the content. 

International Standard Recording Code (ISRC)

The international standard recording code is a unique code that is approved by the International Standard Organization (ISO) to identify audio-visual (AV) recorded materials. Each ISRC code is unique and permanently stored within the recorded media program.

International standard audiovisual number is a unique code that is approved by the International Standard Organization (ISO) in standard 15706 to identify AV materials or portions of AV materials. The International ISAN Agency maintains and coordinates a centralized database of all ISAN records.

International Standard Work Code (ISWC)

International standard work code is a unique code that is approved by the International Standard Organization (ISO) in standard 15707 to identify materials or portions of materials for the music industry. The International ISWC Agency maintains and coordinates a centralized database of all ISWC records.