Network Working Group                                         P. Hoschka
INTERNET DRAFT                                                       W3C
draft-hoschka-smil-media-type-03.txt                       December 1999

                    The application/smil Media Type

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

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   This document specifies the Media Type of the Synchronized Multimedia
   Integration Language (SMIL 1.0, pronounced "smile"). SMIL allows
   integrating a set of independent multimedia objects into a
   synchronized multimedia presentation.

1.  Introduction

   The World Wide Web Consortium has issued a Recommendation [1], which
   defines version 1 of  the Synchronized Multimedia Integration
   Language. This memo provides information about the application/smil
   Media Type.

   The definition is based on the definition of the "application/xml"
   media type [3]. The "application/smil" media type cannot be
   implemented without reading and understanding the document describing
   the "application/xml" media type [3].

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2.  Synchronized Multimedia Integration Language

   SMIL allows integrating a set of independent multimedia objects into
   a synchronized multimedia presentation. Using SMIL, an author can

   1.describe the temporal behavior of the presentation
   2.describe the layout of the presentation on a screen
   3.associate hyperlinks with media objects

   SMIL is defined using XML [2], and the definition of the SMIL media
   type is based on the defintion of XML media types [3].

3.  Registration Information

   Subject: Registration of MIME media type application/smil

   MIME media type name: application

   MIME subtype name: smil

   Required parameters: none

   Optional parameters: charset

   All of the considerations for "application/xml" media type [3] also
   apply to the SMIL media type.

Encoding considerations:

All of the considerations for "application/xml" media type [3] also
apply to the SMIL media type.

Security considerations:

   SMIL documents contain a construct that allows "infinite loops".
   This is indispensible for a multimedia format. However, SMIL clients
   should foresee provisions such as a "stop" button that lets users
   interrupt such an "infinite loop".

   As with HTML, SMIL documents contain links to other media
   (images,sounds, videos, text, ...) and those links are typically
   followed automatically by software, resulting in the transfer of
   files without the explicit request of the user for each one. The
   security considerations of each linked file are those of the
   individual registered types.

   In addition, SMIL has some of the same security considerations as

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   specified in [3], with the following exceptions: the section on XML
   entities does not apply, since SMIL 1.0 disallows entities.

Interoperability considerations:

   SMIL documents contain links to other media objects. The SMIL player
   must be able to decode the media types of these media in order to
   display the whole document. To increase interoperability, SMIL has
   provisions for including alternate versions of a media object in a

Published specification: see [1]

Applications which use this media type:

SMIL players

Additional information:

Semantics of fragment identifiers in URIs: The SMIL media type allows to
append a fragment identifier to a URI pointing to a SMIL resource (e.g.  The semantics of fragment
identifers for SMIL resources are defined in [1].

Magic number(s): none

   All of the considerations for "application/xml" media type [3] also
   apply to the SMIL media type.

File extension(s): .smil, .smi, .sml

NOTE: On the Windows operating system, the ".smi" extension is
used by another format. To avoid conflicts, it is thus
strongly recommended not to use the extension ".smi" for storing
SMIL files on systems running the Windows operating system.

Macintosh File Type Code(s): "TEXT"
Object Identifier(s) or OID(s): none

Person & email address to contact for further information:

The author of this memo.

Intended usage: COMMON

Author/Change controller:

   The SMIL specification is a work product of the World Wide Web

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   Consortium's SYMM Working Group, and was edited by:

   Philipp Hoschka (

   The W3C has change control over the SMIL specification.

5.  References

   [1]  "Synchronized Multimedia Integration Language (SMIL) 1.0
        Specification", W3C Recommendation REC-smil-19980615,, July 1998.

   [2]  "Extensible Markup Language (XML) 1.0", W3C Recommendation
        February 1998.

   [3]  E. J. Whitehead Jr., M. Murata. "XML Media Types", RFC 2376,
        UC Irvine, Fuji Xerox Info. Systems, July 1998.

6.  Author's Address

   Philipp Hoschka
   2004, route des Lucioles - B.P. 93
   06902 Sophia Antipolis Cedex

   Phone: +33 (0)492387984
   Fax:+33 (0)493657765

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