Content Duration MIME Header Definition
draft-ietf-vpim-vpimv2r2-dur-03

The information below is for an old version of the document that is already published as an RFC
Document Type RFC Internet-Draft (vpim WG)
Authors Glenn Parsons  , Gregory Vaudreuil 
Last updated 2015-10-14 (latest revision 2002-02-15)
Stream Internet Engineering Task Force (IETF)
Formats plain text pdf htmlized bibtex
Stream WG state (None)
Document shepherd No shepherd assigned
IESG IESG state RFC 3803 (Draft Standard)
Consensus Boilerplate Unknown
Telechat date
Responsible AD Ned Freed
IESG note 3803
Send notices to <jwn2@qualcomm.com>
Network Working Group                                    Greg Vaudreuil
     Internet Draft                                      Lucent Technologies
     Expires in six months                                     Glenn Parsons
     Obsoletes:  RFC 2424                                    Nortel Networks
                                                           February 14, 2002
      
      
                                  Content Duration 
                               MIME Header Definition 
         
                        <draft-ietf-vpim-vpimv2r2-dur-03.txt> 
      
         
     Status of this Memo 
      
        This document is an Internet-Draft and is in full conformance with all 
        provisions of Section 10 of RFC2026.  
         
        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-Drafts. 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 
        http://www.ietf.org/ietf/1id-abstracts.txt  
         
        The list of Internet-Draft Shadow Directories can be accessed at 
        http://www.ietf.org/shadow.html. 
         
         
      Abstract  
         
        This document describes the MIME header Content-Duration that is 
        intended for use with any time varying media content (typically   
        audio/* or video/*).  
         
        This document obsoletes RFC 2424. 
         
         
     Copyright Notice  
      
        Copyright (C) The Internet Society (2002).  All Rights Reserved. 
         
         

     Vaudreuil & Parsons    Expires: August 14, 2002                      1 



     Internet Draft             Content Duration          February 14, 2002 
      
     1. Introduction 
         
        This document describes the MIME header Content-Duration that is 
        intended for use with any time varying media content (typically   
        audio/* or video/*). The length of time is represented in seconds   
        without any units indication. 
         
        This document obsoletes RFC 2424. 
         
        The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
        "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this 
        document are to be interpreted as described in RFC-2119 [REQ]. 
      
     2. Content-Duration Header Field 
      
        Time varying media contents, for example, a spoken voice message or a 
        video clip, have an inherent time duration.  Many audio and video 
        encodings may include their duration as header information or may allow 
        accurate calculation based on the byte length of the data. 
        However, it may be useful to present the time duration of the content in 
        a MIME header to allow its simple determination without dealing with the 
        actual content. 
         
         
     2.1 Syntax 
         
        The Content-Duration field's value is a single number specifying the 
        time duration in seconds of the content.  Formally: 
         
        duration := "Content-Duration" ":" 1*10DIGIT 
         
        Note that practically (though highly unlikely in MIME media), the upper 
        bound on the numerical value of the time duration is (2^^31 -1) or 
        2147483647. 
         
     2.2 Semantics 
         
        This field represents the time duration of the associated time varying 
        media content. The time duration is noted in seconds with no units tag. 
        The time value should be exact, however the exact value of the time 
        duration cannot be known without opening the content and playing it. If 
        an exact value must be known, then the latter method should be used. 
        This mechanism simply allows placing a sender determined time duration 
        value in the header for easy access. 
         
        Though there are several ways to present this duration to the recipient 
        (e.g. with the inbox headers, when audio attachment opened), the actual 
        use of this field on reception is a local implementation issue. 
      
     Vaudreuil & Parsons      Expires April 22, 2002               [Page 2] 



     Internet Draft             Content Duration          February 14, 2002 
      
     2.3 Example 
         
        In this example the content duration represents 33 seconds: 
         
             Content-Duration: 33 
         
     3. VPIM Usage 
         
        The Content-Duration header field for the audio/32KADPCM sub-type is a 
        useful component of the VPIM specification [VPIM2]. All VPIM Messages 
        MUST contain this sub-type to carry the audio of a voice message. It may 
        be useful in some instances (e.g. viewing on a simple MIME or non-MIME 
        desktop) to have the time duration of the voice message available 
        without having to open the audio content. 
         
         
     4. Security Considerations 
      
        This definition introduces the option of explicitly identifying the   
        time duration of an audio/* or video/* content outside of the binary 
        data that forms the content. In some environments (though likely not the 
        majority), the identification of the actual time duration in a header 
        field may be a security issue and as a result should not be noted. 
        Reliance on the time indicated in this header field cannot be trusted 
        for the purposes of determining the exact size of the data. The exact 
        length of the data must be determined by examining the data itself. 
         
         
     5. References 
         
        [DUR] G. Parsons and G. Vaudreuil, "Content Duration MIME Header 
        Definition", RFC 2424, September 1998.  
         
        [MIME2] Freed, N., and N. Borenstein, "Multipurpose Internet Mail 
        Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996. 
         
        [VPIM2] Vaudreuil, G., and G. Parsons, "Voice Profile for Internet 
        Mail - version 2", RFC 2421, September 1998. 
         
        [VPIM2R2] Vaudreuil, G., and G. Parsons, "Voice Profile for Internet 
        Mail - version 2", <draft-ietf-vpim-vpimv2r2-04.txt>, October 22, 2001. 
         
        [REQ] S. Bradner, "Key words for use in RFCs to Indicate Requirement 
        Levels", RFC 2119, March 1997. 
         
         

      
     Vaudreuil & Parsons      Expires April 22, 2002               [Page 3] 



     Internet Draft             Content Duration          February 14, 2002 
      
     6. Authors' Addresses 
         
        Glenn W. Parsons 
        Nortel Networks 
        P.O. Box 3511, Station C 
        Ottawa, ON  K1Y 4H7 
        Canada 
         
        Phone: +1-613-763-7582 
        Fax:   +1-613-763-2697 
        Email: gparsons@nortelnetworks.com 
         
        Gregory M. Vaudreuil 
        Lucent Technologies 
        7291 Williamson Rd 
        Dallas, TX  75214 
        United States 
         
        Phone/Fax: +1-972-733-2722 
        Email: gregv@ieee.org 
         
         
     7. Changes from RFC 2424 
         
        Only editoral and boilerplate changes from RFC 2424 have been made to 
        this document. 
         

      
     Vaudreuil & Parsons      Expires April 22, 2002               [Page 4] 



     Internet Draft             Content Duration          February 14, 2002 
      
     8. Full Copyright Statement 
      
        Copyright (C) The Internet Society (2002).  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 assigns. 
         
        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. 

      
     Vaudreuil & Parsons      Expires April 22, 2002               [Page 5]