RFC 3614 INFORMATIONAL NAMING · URN · STANDARDS

A Uniform Resource Name (URN) Namespace for the Motion Picture Experts Group (MPEG)

A permanent naming system for standards and resources produced by MPEG.

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PUBLISHED
September 2003
AUTHORS
J. Smith
STREAM
INDEPENDENT
NAMESPACE IDENTIFIER
mpeg
REGISTRATION DATE
November 20, 2001
SCOPE
Global
STANDARD NAMES COVERED
mpeg1, mpeg2, mpeg4, mpeg7, mpeg21, and future standards
DOI
10.17487/RFC3614

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗
Network Working Group                                           J. Smith
Request for Comments: 3614              IBM T. J. Watson Research Center
Category: Informational                                   September 2003


            A Uniform Resource Name (URN) Namespace for the
                  Motion Picture Experts Group (MPEG)

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document describes a Uniform Resource Name (URN) namespace for
   the Motion Picture Experts Group (MPEG) for naming persistent
   resources as part of the MPEG standards.  Example resources include
   technical documents and specifications, eXtensible Markup Language
   (XML) Schemas, classification schemes, XML Document Type Definitions
   (DTDs), namespaces, style sheets, media assets, and other types of
   resources produced or managed by MPEG.

1.  Introduction

   MPEG is a working group of the International Organization for
   Standardization (ISO) and International Engineering Consortium (IEC)
   in charge of the development of standards for coded representation of
   digital audio and video.  MPEG has produced MPEG-1, the standard on
   which such products as Video CD and MP3 are based, MPEG-2, the
   standard on which such products as Digital Television set top boxes
   and DVD are based, MPEG-4, the standard for multimedia for the fixed
   and mobile web, and MPEG-7, "Multimedia Content Description
   Interface", the standard for description and search of audio and
   visual content. Work on MPEG-21, "Multimedia Framework" is currently
   underway.

   MPEG would like to assign unique, permanent, location-independent
   names based on URNs for some resources it produces or manages.

   This namespace specification is for a formal namespace.

2.  Specification Template

   Namespace ID:

      "mpeg"

   Registration Information:

      Version: 1
      Date: 2001-11-20

   Declared registrant of the namespace:

      Name:           John R. Smith
      Title:          Chair, MPEG MDS Subgroup
      Affiliation:    IBM T. J. Watson Research Center
      Address:        30 Saw Mill River Road
                      Hawthorne, NY 10532 USA
      Phone:          +1 (914) 784-7320
      Email:          jrsmith@watson.ibm.com

   Declaration of structure:

      URNs assigned by MPEG will have the following hierarchical
      structure based on the organizational structure of the MPEG
      standards:

         urn:mpeg:{standard name}:{assigned US-ASCII string}

      where "{standard name}" is a US-ASCII string that conforms to URN
      Syntax requirements ([RFC2141]) and corresponds to the name of an
      MPEG standard (such as "mpeg1", "mpeg2", "mpeg4", "mpeg7",
      "mpeg21", and

      "{assigned US-ASCII string}" is a US-ASCII string that conforms to
      URN Syntax requirements ([RFC2141]).

      The individual URNs shall be assigned by MPEG through the process
      of development of MPEG standards.

   Relevant ancillary documentation:

      None

   Identifier uniqueness considerations:

      MPEG shall establish unique identifiers as appropriate.

      Uniqueness is guaranteed as long as the assigned string is never
      reassigned for a given standard name and that the standard name is
      never reassigned.

   Identifier persistence considerations:

      MPEG is committed to maintaining the accessibility and persistence
      of all resources that are officially assigned URNs by the
      organization.

      Persistence of identifiers is dependent upon suitable delegation
      of resolution at the level of "standard name"(s), and persistence
      of standard name assignment.

   Process of identifier assignment:

      Assignment is limited to the owner and those authorities that are
      specifically designated by the owner.  MPEG may designate portions
      of its namespace for assignment by other parties.

   Process of identifier resolution:

      The owner will develop and maintain "URN catalogs" that map all
      assigned URNs to Uniform Resource Locators (URLs) specifically to
      enable Web-based resolution of named resources.  In the future an
      interactive online resolution system may be developed to automate
      this process.

      The owner will authorize additional resolution services as
      appropriate.

   Rules for Lexical Equivalence:

      The "standard name" is case-insensitive.  Thus, the portion of the
      URN:

         urn:mpeg:{standard name}:

      is case-insensitive for matches.  The remainder of the identifier
      must be considered case-sensitive.

   Conformance with URN Syntax:

      No special considerations.

   Validation mechanism:

      None specified.  The owner will develop and maintain URN catalogs.

      The presence of a URN in a catalog indicates that it is valid.

   Scope:

      Global

3.  Examples

   The following examples are not guaranteed to be real.  They are
   presented for pedagogical reasons only.

      urn:mpeg:mpeg7:schema:2001
      urn:mpeg:mpeg7:cs:VideoDomainCS:2001
      urn:mpeg:mpeg7:cs:GenreCS:2001
      urn:mpeg:mpeg7:cs:ContentCS:2001

4.  Namespace Considerations

   URN assignment procedures:

      The individual URNs shall be assigned through the process of
      development of MPEG standards by the Moving Picture Experts Group
      (MPEG), which is a working group of ISO/IEC.

   URN resolution/delegation:

      The resolution and delegation shall be determined through the
      process of development of MPEG standards by the Moving Picture
      Experts Group (MPEG).  MPEG has developed requests for
      registration authority for MPEG-7 classification schemes and
      MPEG-21 identification systems. These registration authorities
      shall be responsible for corresponding parts of MPEG namespace.

   Type of resources to be identified:

      Types of resources to be identified include XML schema definition
      files, classification schemes, identification systems.

   Type of services to be supported:

      Types of services supported include controlled term lookup in
      classification schemes, resolution of ids in identification
      systems.

5.  Community Considerations

   Open assignment and use of identifiers within the namespace:

      With on-going development of MPEG standards, MPEG shall establish
      requirements for assignment and use of identifiers within MPEG
      namespace.  MPEG has already established requirements for
      assignment and use of MPEG-7 classification schemes under MPEG
      namespace. A registration authority shall have the responsibility
      for processing third party requests for registering classification
      schemes.

   Open operation of resolution servers for the namespace (server):

      With on-going development of MPEG standards, MPEG shall establish
      requirements and seek candidates for operating resolution servers
      as appropriate.

   Creation of software that can meaningfully resolve and access
   services for the namespace (client):

      With on-going development of MPEG standards, MPEG shall develop
      reference software implementations of its standards.

6.  Security Considerations

   There are no additional security considerations other than those
   normally associated with the use and resolution of URNs in general.

7.  IANA Considerations

   The IANA has registered formal URN namespace 12, to MPEG within the
   IANA registry of URN NIDs.

8.  Normative References

   [RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997.

9.  Author's Address

   John R. Smith
   IBM T. J. Watson Research Center
   30 Saw Mill River Road
   Hawthorne, NY 10532 USA

   Phone: 1 (914) 784-7320
   EMail: jrsmith@watson.ibm.com

10.  Full Copyright Statement

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assignees.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.

AI ELI5

On this page
PROBLEMThe Motion Picture Experts Group (MPEG) produces many standards and related resources like XML schemas, classification schemes, and specifications. These resources need persistent, globally unique names that do not change when servers or formats change.
MECHANISMA URN namespace named urn:mpeg is registered with a two-level hierarchical structure: urn:mpeg:{standard name}:{assigned string}. MPEG controls all assignments and maintains catalogs mapping URNs to resources.
PERSISTENT NAMES FOR MPEGMPEG can assign and resolve persistent names to its standards and resources, supporting discovery, resolution, and identification services.

§1MPEG and Its Resource Naming Needs

The Motion Picture Experts Group (MPEG) is a working group of ISO and IEC that develops international standards for coded representation of digital audio and video. MPEG has produced MPEG-1 (foundation for Video CD and MP3), MPEG-2 (foundation for DVD and digital television), MPEG-4 (multimedia for the web), MPEG-7 (multimedia content description), and is developing MPEG-21 (multimedia framework).

MPEG produces many resources beyond protocol specifications: XML schemas, classification schemes, identification systems, technical documents, and other standards-related materials. To make these resources discoverable and persistent, MPEG requested a formal URN namespace. A Uniform Resource Name (URN) is a persistent, location-independent identifier that can be resolved to find the actual resource, no matter where it is stored.

MPEG makes video standards and tools. They need permanent names for each schema, document, and definition so people can find them anywhere.

§2URN Structure and Naming Hierarchy

MPEG URNs follow the form urn:mpeg:{standard name}:{assigned US-ASCII string}. The standard name corresponds to an MPEG standard like mpeg1, mpeg2, mpeg4, mpeg7, or mpeg21. The assigned string is any US-ASCII string that conforms to URN syntax.

For example, valid MPEG URNs include urn:mpeg:mpeg7:schema:2001 and urn:mpeg:mpeg7:cs:GenreCS:2001. The standard name is case-insensitive for matching purposes, meaning MPEG7 and mpeg7 refer to the same standard. Everything after the standard name is case-sensitive.

Uniqueness is guaranteed as long as the assigned string is never reused for a given standard and the standard name itself is never reassigned. Each URN is assigned through the development process of the MPEG standards.

Names look like urn:mpeg:mpeg7:myresource. The first part says what MPEG standard, the second part says what specific thing. MPEG decides what gets a name.

§3Assignment, Resolution, and Persistence

MPEG controls all URN assignments, though it may designate portions of its namespace for assignment by other parties (such as registration authorities for MPEG-7 classification schemes). Individual URNs are assigned through the normal MPEG standards development process.

MPEG develops and maintains URN catalogs that map all assigned URNs to Uniform Resource Locators (URLs), enabling Web-based resolution of named resources. In the future, MPEG may develop an interactive online resolution system to automate the process. The presence of a URN in a catalog indicates that it is valid.

MPEG is committed to maintaining the accessibility and persistence of all resources officially assigned URNs. This commitment depends on proper delegation at the standard-name level and persistence of standard-name assignments. MPEG may authorize additional resolution services as needed.

MPEG keeps a directory mapping each permanent name to where the file actually is. Anyone can ask MPEG 'where is this name?' and get pointed to the resource.

§4Types of Resources and Services

Resources that can be named include XML Schema Definition files, classification schemes, identification systems, and other materials produced as part of MPEG standards. The namespace is broad enough to cover the full range of MPEG's output.

Services that can be supported include controlled term lookup in classification schemes and resolution of identifiers in identification systems. As MPEG standards evolve and new resource types are produced, the namespace can accommodate them without modification, since MPEG controls the structure and can add new standard names as needed.

MPEG can name schemas, lists of categories, identification codes, and anything else it produces. People can use the names to look things up.

§5Community and Future Development

With ongoing development of MPEG standards, MPEG establishes requirements for assignment and use of identifiers within the namespace. For example, registration authorities have responsibility for processing third-party requests to register MPEG-7 classification schemes. MPEG continues to develop reference software implementations to help clients resolve and use URNs in MPEG standards.

This URN namespace allows MPEG to maintain persistence and discoverability of its resources over time, supporting the international multimedia standards community in adopting and implementing MPEG specifications.

MPEG keeps adding new standards, and the naming system grows with them. The permanent names ensure that old and new resources can always be found.

§6References