[Search] [pdf|bibtex] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 rfc4539                              Informational
Network Working Group                                         T. Edwards
Internet-Draft                                                       PBS
Expires: September 4, 2006                                 March 3, 2006

    Media Type Registration for SMPTE Material Exchange Format (MXF)

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at

   The list of Internet-Draft Shadow Directories can be accessed at

   This Internet-Draft will expire on September 4, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).


   This document serves to register a media type for the SMPTE Material
   Exchange Format (MXF).  MXF, defined by SMPTE 377M, is a standard
   wrapper format developed for the interchange of audiovisual material,
   including both audiovisual essence and rich metadata.

Edwards                 Expires September 4, 2006               [Page 1]

Internet-Draft       Media Type Registration for MXF          March 2006

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Security Considerations . . . . . . . . . . . . . . . . . . . . 3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
     3.1.  Media Type for SMPTE Material Exchange Format (MXF) . . . . 4
   4.  RFC Editor Considerations . . . . . . . . . . . . . . . . . . . 6
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     5.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     5.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 8
   Intellectual Property and Copyright Statements  . . . . . . . . . . 9

Edwards                 Expires September 4, 2006               [Page 2]

Internet-Draft       Media Type Registration for MXF          March 2006

1.  Introduction

   The present document registers a media type for SMPTE Material
   Exchange Format (MXF).  MXF, defined by SMPTE 377M [SMPTE377M], is a
   standard wrapper format developed for the interchange of audiovisual
   material, including both audiovisual essence and rich metadata.

   Essence is the raw video, audio, and data streams contained and
   described by MXF.  Metadata carried by MXF includes structural
   metadata and descriptive metadata.  Structural metadata relates to
   the structure and capabilities of the MXF file, and is generally
   required for proper decoding.  Some examples of structural metadata
   are descriptions of essence types, information to help synchronize
   playout of audio and video, and content length.  Descriptive metadata
   gives information about the program content in the file, and is not
   essential for decoding.  Some examples of descriptive metadata are
   program title, actors, and scene descriptions.  The essence in MXF
   files may itself carry data, such as vertical blanking interval data
   used for carriage of Closed Captioning and other purposes.

   MXF is an important tool in providing interoperation between
   different video systems as well as digital cinema systems.  MXF also
   aids in the development of video production and distribution
   workflows that are more efficient, multi-vendor, file-based, and IT-

   SMPTE currently has standards for the mapping of the following
   essence types to the MXF generic container: MPEG (including MPEG-1
   and MPEG-2 video streams, as well as MPEG audio), DV-DIF (Digital
   Video Digital Interface Format for the DV family of related video
   encodings), Uncompressed Pictures, SDTI-CP (Serial Digital Transport
   Interface Content Package for delivering packetized audiovisual
   content over the SDI interface), D-10 (a specialized video stream
   incorporating MPEG-2 4:2:2P@ML), D-11 (a high-definition video
   compression standard), AES3 audio, Broadcast Wave audio, and A-Law
   audio.  The flexibility of the MXF generic container allows for the
   possibility of mappings of additional essence types in the future.

   The media type defined here is needed to correctly identify MXF files
   when they are served over HTTP or other network connections, included
   in multi-part documents, indexed by operating systems and digital
   asset management systems, or when used in other places where media
   types are used.

2.  Security Considerations

   Security requirements for the application/mxf media type are

Edwards                 Expires September 4, 2006               [Page 3]

Internet-Draft       Media Type Registration for MXF          March 2006

   discussed in the IANA media type registration (Section 3.1).

3.  IANA Considerations

   The present document requests that IANA registers the media type
   application/mxf as specified in Section 3.1.  The registration uses
   the template present in [RFC4288].

3.1.  Media Type for SMPTE Material Exchange Format (MXF)

      To: ietf-types@iana.org
      Subject: Registration of media type application/mxf

      Type name: application

      Subtype name: mxf

      Required parameters: none

      Optional parameters: ULs

      The optional parameter ULs is a single Uniform Resource Name
      (URN), or a comma-separated list of multiple URNs of SMPTE
      Universal Labels (which are defined by SMPTE 400M [SMPTE400M]).

      This optional parameter provides hints to the decoder regarding
      the structure of the MXF file, which could include Operational
      Pattern, essence types, descriptive metadata schemes, and other
      elements that are identified by their SMPTE Universal Label.

      SMPTE Universal Labels are Object Identifiers (OIDs) as specified
      by [ASN1].  Thus a URN of a SMPTE Universal Label can use the OID
      URN namespace specified in [RFC3061], or any other future URN
      namespace that is appropriate for SMPTE Universal Labels.

      Note that, per [RFC2045], some characters (including the comma
      used to separate multiple values) require that the entire
      parameter value be enclosed in quotes.

      Below is an example of use of the optional parameter.  The two
      SMPTE Universal Labels indicate that the MXF file utilizes the
      OP1a Operational Pattern and contains IEC DV video at 25 Mbps, 525
      lines, 59.94 fps interlaced essence.

Edwards                 Expires September 4, 2006               [Page 4]

Internet-Draft       Media Type Registration for MXF          March 2006

      Content-Type: application/mxf;

      Encoding considerations: binary

      Security considerations: Application/mxf objects are not signed
      but may be partially encrypted internally.  External security
      mechanisms must be employed to ensure content confidentiality.
      MXF, through metadata extensions, may allow executable code to be
      transferred in the file.  It is suggested that no unauthenticated
      executables decoded from an MXF file be executed.  Some compressed
      essence types carried in MXF may carry a risk that certain
      pathological bitstreams could lead to potential denial-of-service
      attacks against these essence decoders.

      Interoperability considerations: MXF provides a standard wrapping
      for a number of audio and video essence types according to a
      number of different Operational Patterns (OP).  Thus
      interoperability depends upon the MXF file decoder having the
      capability to match the features of the MXF file encoder.  An
      Application Specification (AS) can ensure that MXF encoders and
      decoders can effectively interoperate.

      Published specification: RFC XXXX, SMPTE 377M [SMPTE377M]

      Applications which use this media type: MXF is a wrapper for many
      types of audio and video essence types in use by many applications
      in the broadcast and digital cinema industries.  These include
      non-linear editing systems, video servers, video camera systems,
      digital asset management systems, and digital video distribution

      Additional information:

         Magic number(s): none

         File extension(s): .mxf

         Macintosh File Type Code(s): "mxf "

      Person & email address to contact for further information:

      Thomas Edwards
      email: tedwards@pbs.org

Edwards                 Expires September 4, 2006               [Page 5]

Internet-Draft       Media Type Registration for MXF          March 2006

      Intended usage: COMMON

      Restrictions on usage: none

      Author/Change controller:

      Thomas Edwards
      email: tedwards@pbs.org

4.  RFC Editor Considerations

   The reference to RFC XXXX in the media type registration
   (Section 3.1) should be replaced with the actual RFC number of this
   document when it is issued.

   Please remove this section before publication as RFC.

5.  References

5.1.  Normative References

              Society of Motion Picture and Television Engineers,
              "Material Exchange Format (MXF) File Format
              Specification", SMPTE 377M-2004, <http://www.smpte.org>.

              Society of Motion Picture and Television Engineers, "SMPTE
              Labels Structure", SMPTE 400M-2004,

5.2.  Informative References

   [ASN1]     International Telephone and Telegraph Consultative
              Committee, "Specification of Basic Encoding Rules for
              Abstract Syntax Notation One (ASN.1)",
              CCITT Recommendation X.209, January 1988.

   [RFC2045]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part One: Format of Internet Message
              Bodies", RFC 2045, November 1996.

   [RFC3061]  Mealling, M., "A URN Namespace of Object Identifiers",
              RFC 3061, February 2001.

   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and

Edwards                 Expires September 4, 2006               [Page 6]

Internet-Draft       Media Type Registration for MXF          March 2006

              Registration Procedures", BCP 13, RFC 4288, December 2005.

Edwards                 Expires September 4, 2006               [Page 7]

Internet-Draft       Media Type Registration for MXF          March 2006

Author's Address

   Thomas G. Edwards
   1320 Braddock Place
   Alexandria, VA  22314

   Phone: +1 703 739 5000
   Email: tedwards@pbs.org
   URI:   http://www.pbs.org

Edwards                 Expires September 4, 2006               [Page 8]

Internet-Draft       Media Type Registration for MXF          March 2006

Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at

Disclaimer of Validity

   This document and the information contained herein are provided on an

Copyright Statement

   Copyright (C) The Internet Society (2006).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights.


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

Edwards                 Expires September 4, 2006               [Page 9]