





Network Working Group                                      M. Froumentin
Request for Comments: 4267                                           W3C
Category: Informational                                    November 2005


            The W3C Speech Interface Framework Media Types:
   application/voicexml+xml, application/ssml+xml, application/srgs,
  application/srgs+xml, application/ccxml+xml, and application/pls+xml

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 (2005).

Abstract

   This document defines the media types for the languages of the W3C
   Speech Interface Framework, as designed by the Voice Browser Working
   Group in the following specifications: the Voice Extensible Markup
   Language (VoiceXML), the Speech Synthesis Markup Language (SSML), the
   Speech Recognition Grammar Specification (SRGS), the Call Control XML
   (CCXML), and the Pronunciation Lexicon Specification (PLS).

Table of Contents

   1. Introduction ....................................................2
   2. Registration of application/voicexml+xml, application/ssml+xml,
      application/srgs+xml, application/ccxml+xml, and
      application/pls+xml .............................................3
      2.1. Encoding Considerations ....................................3
      2.2. Interoperability Considerations ............................3
      2.3. Published Specifications ...................................3
      2.4. Applications that Use These Media Types ....................4
      2.5. Security Considerations ....................................4
      2.6. Additional Information .....................................4
           2.6.1. Magic Numbers .......................................4
           2.6.2. File Extensions .....................................4
           2.6.3. Fragment Identifiers ................................5
           2.6.4. Macintosh File Type Code ............................5
           2.6.5. Person and Email Address to Contact for
                  Further Information .................................5
           2.6.6. Intended Usage ......................................5
           2.6.7. Change Controller ...................................5



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   3. Registration of application/srgs ................................5
      3.1. Encoding Considerations ....................................5
      3.2. Interoperability Considerations ............................5
      3.3. Published Specifications ...................................5
      3.4. Applications That Use This Media Type ......................6
      3.5. Security Considerations ....................................6
      3.6. Additional Information .....................................6
           3.6.1. Magic Numbers .......................................6
           3.6.2. File Extensions .....................................6
           3.6.3. Macintosh File Type Code ............................6
           3.6.4. Person and Email Address to Contact for
                  Further Information .................................7
           3.6.5. Intended Usage ......................................7
           3.6.6. Change Controller ...................................7
   4. IANA Considerations .............................................7
   5. Normative References ............................................7

1.  Introduction

   This specification defines the media types of the Voice Extensible
   Markup Language (VoiceXML), the Speech Synthesis Markup Language
   (SSML), the Speech Recognition Grammar Specification (SRGS), the Call
   Control XML (CCXML), and the Pronunciation Lexicon Specification
   (PLS), the specifications of the W3C Speech Interface Framework.

   VoiceXML ([VoiceXML2.0]) is an Extensible Markup Language (XML)
   designed for creating audio dialogs that feature synthesized speech,
   digitized audio, recognition of spoken and DTMF key input, recording
   of spoken input, telephony, and mixed initiative conversations.  The
   associated media type defined in this document is
   "application/voicexml+xml".

   The Speech Synthesis Markup Language specification (SSML) defines an
   XML-based markup language for assisting the generation of synthetic
   speech in Web and other applications.  The essential role of SSML is
   to provide authors of synthesizable content a standard way to control
   aspects of speech such as pronunciation, volume, pitch, and rate,
   across different synthesis-capable platforms.  The associated media
   type defined in this document is "application/ssml+xml".

   The Speech Recognition Grammar Specification (SRGS) defines syntax
   for representing grammars for use in speech recognition so that
   developers can specify the words and patterns of words to be listened
   for by a speech recognizer.  The syntax of the grammar format exists
   in two forms, an Augmented BNF (ABNF) Form and an XML Form.  The
   respective media types defined in this document are
   "application/srgs" and "application/srgs+xml".




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   The Call Control EXtensible Markup Language (CCXML) is an XML
   designed to provide telephony call control support for dialog
   systems, such as VoiceXML.  The associated media type defined in this
   document is "application/ccxml+xml".

   The Pronunciation Lexicon Specification (PLS) defines an XML syntax
   for specifying pronunciation lexicons to be used by speech
   recognition and speech synthesis engines in voice browser
   applications.  The associated media type defined in this document is
   "application/pls+xml".

2.  Registration of application/voicexml+xml, application/ssml+xml,
    application/srgs+xml, application/ccxml+xml, and application/pls+xml

   MIME media type name: application

   MIME subtype names: voicexml+xml, ssml+xml, srgs+xml, ccxml+xml,
   pls+xml

   Required parameters: none

   Optional parameters:

      "charset": This parameter has identical semantics to the charset
      parameter of the "application/xml" media type as specified in RFC
      3023 [RFC3023].

2.1.  Encoding Considerations

   Identical to those of "application/xml" as described in RFC 3023
   [RFC3023], section 3.2.

2.2.  Interoperability Considerations

   There are no known interoperability issues.

2.3.  Published Specifications

   Voice Extensible Markup Language 2.0 [VoiceXML2.0]

   Voice Extensible Markup Language 2.1 [VoiceXML2.1]

   Speech Synthesis Markup Language (SSML) Version 1.0 [SSML]

   Speech Recognition Grammar Specification Version 1.0 [SRGS]

   Voice Browser Call Control: CCXML Version 1.0 [CCXML]




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   Pronunciation Lexicon Specification (PLS) Version 1.0 [PLS]

2.4.  Applications that Use These Media Types

   Various W3C Speech Interface Framework implementations use these
   media types.

2.5.  Security Considerations

   Several instructions in the cited specifications may cause arbitrary
   Uniform Resource Identifiers (URIs) to be dereferenced.  In this
   case, the security issues of [RFC3986], section 7, should be
   considered.

   In addition, because of the extensibility features of those
   specifications, it is possible that the registered media types may
   describe content that has security implications beyond those
   described here.  However, if the processor follows only the normative
   semantics of the specifications, this content will be ignored.  Only
   in the case where the processor recognizes and processes the
   additional content, or where further processing of that content is
   dispatched to other processors, would security issues potentially
   arise.  And in that case, they would fall outside the domain of this
   registration document.

2.6.  Additional Information

2.6.1.  Magic Numbers

   Although no byte sequences can be counted on to always be present,
   XML MIME entities in ASCII-compatible charsets (including UTF-8)
   often begin with hexadecimal 3C 3F 78 6D 6C ("<?xml"), and those in
   UTF-16 often begin with hexadecimal FE FF 00 3C 00 3F 00 78 00 6D 00
   6C or FF FE 3C 00 3F 00 78 00 6D 00 6C 00 (the Byte Order Mark (BOM)
   followed by "<?xml").  For more information, see Appendix F of [XML].

2.6.2.  File Extensions

   VoiceXML files: .vxml

   SSML files: .ssml

   SRGS files (XML syntax): .grxml

   CCXML files: .ccxml

   PLS files: .pls




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2.6.3.  Fragment Identifiers

   Identical to that of "application/xml" as described in RFC 3023
   [RFC3023], section 5.

2.6.4.  Macintosh File Type Code

   "TEXT"

2.6.5.  Person and Email Address to Contact for Further Information

   World Wide Web Consortium <web-human@w3.org>

2.6.6.  Intended Usage

   COMMON

2.6.7.  Change Controller

   The Speech Interface Framework specifications set is a work product
   of the World Wide Web Consortium's Voice Browser Working Group.  The
   W3C has change control over these specifications.

3.  Registration of application/srgs

   MIME media type name: application

   MIME subtype names: srgs

   Required parameters: none

   Optional parameters: none

3.1.  Encoding Considerations

   The ABNF Form of SRGS follows the character encoding handling defined
   for XML: an ABNF grammar processor must accept both the UTF-8 and
   UTF-16 encodings of ISO/IEC 10646 and may support other character
   encodings.

3.2.  Interoperability Considerations

   There are no known interoperability issues.

3.3.  Published Specifications

   Speech Recognition Grammar Specification Version 1.0 [SRGS]




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3.4.  Applications That Use This Media Type

   Various SRGS implementations use this media type.

3.5.  Security Considerations

   Several instructions in SRGS may cause arbitrary URIs to be
   dereferenced.  In this case, the security issues of [RFC3986],
   section 7, should be considered.

   In addition, because of the extensibility features of SRGS, it is
   possible that the registered media types may describe content that
   has security implications beyond those described here.  However, if
   the processor follows only the normative semantics of the
   specifications, this content will be ignored.  Only in the case where
   the processor recognizes and processes the additional content, or
   where further processing of that content is dispatched to other
   processors, would security issues potentially arise.  In that case,
   they would fall outside the domain of this registration document.

3.6.  Additional Information

3.6.1.  Magic Numbers

   The ABNF self-identifying header must be present in any legal stand-
   alone ABNF Form grammar document.  The first character of an ABNF
   document must be the "#" symbol (x23) unless preceded by an optional
   XML 1.0 byte order mark.  The ABNF byte order mark follows the XML
   definition and requirements.  For example, documents encoded in UTF-
   16 must begin with the byte order mark.  The optional byte order mark
   and required "#" symbol must be followed immediately by the exact
   string "ABNF" (x41 x42 x4d x46) or the appropriate equivalent for the
   document's encoding (e.g., for UTF-16 little-endian: x23 x00 x41 x00
   x42 x00 x4d x00 x46 x00).  If the byte order mark is absent on a
   grammar encoded in UTF-16, then the grammar processor should perform
   auto-detection of character encoding in a manner analogous to auto-
   detection of character encoding in XML.  Next follows a single-space
   character (x20) and the required version number, which is "1.0" for
   this specification (x31 x2e x30).

3.6.2.  File Extensions

   .gram

3.6.3.  Macintosh File Type Code

   "TEXT"




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3.6.4.  Person and Email Address to Contact for Further Information

   World Wide Web Consortium <web-human@w3.org>

3.6.5.  Intended Usage

   COMMON

3.6.6.  Change Controller

   The SRGS specification is a work product of the World Wide Web
   Consortium's Voice Browser Working Group.  The W3C has change control
   over the SRGS specification.

4.  IANA Considerations

   This document registers six new MIME media types, according to the
   registrations in Section 2 and Section 3.

5.  Normative References

   [CCXML]       Auburn, RJ., Ed., "Voice Browser Call Control: CCXML
                 Version 1.0, W3C Working Draft", January 2005,
                 <http://www.w3.org/TR/2005/WD-ccxml-20050111/>.

   [PLS]         Baggia, P., Ed., "Pronunciation Lexicon Specification
                 (PLS) Version 1.0, W3C Working Draft", February 2005,
                 <http://w3.org/TR/2005/WD-pronunciation-lexicon-
                 20050214/>.

   [RFC3986]     Berners-Lee, T., Fielding, R., and L. Masinter,
                 "Uniform Resource Identifier (URI): Generic Syntax",
                 STD 66, RFC 3986, January 2005.

   [RFC3023]     Murata, M., St. Laurent, S., and D. Kohn, "XML Media
                 Types", RFC 3023, January 2001.

   [SRGS]        Hunt, A., Ed. and S. McGlashan, Ed., "Speech
                 Recognition Grammar Specification Version 1.0, W3C
                 Recommendation", March 2004,
                 <http://www.w3.org/TR/2004/REC-speech-grammar-
                 20040316/>.

   [SSML]        Burnett, D., Ed., Walker, M., Ed., and A. Hunt, Ed.,
                 "Speech Synthesis Markup Language (SSML) Version 1.0,
                 W3C Recommendation", September 2004,
                 <http://www.w3.org/TR/2004/REC-speech-synthesis-
                 20040907/>.



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   [VoiceXML2.0] McGlashan, S., Ed., "Voice Extensible Markup Language
                 (VoiceXML) Version 2.0, W3C Recommendation", March
                 2004, <http://www.w3.org/TR/2004/REC-voicexml20-
                 20040316/>.

   [VoiceXML2.1] Oshry, M., Ed., "Voice Extensible Markup Language
                 (VoiceXML) Version 2.1, W3C Working Draft", July 2004,
                 <http://www.w3.org/TR/2004/WD-voicexml21-20040728/>.

   [XML]         Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E.,
                 and F. Yergeau, "Extensible Markup Language (XML) 1.0
                 (Third Edition)", February 2004,
                 <http://www.w3.org/TR/2004/REC-xml-20040204/>.

Author's Address

   Max Froumentin
   World Wide Web Consortium

   EMail: mf@w3.org































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Full Copyright Statement

   Copyright (C) The Internet Society (2005).

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Acknowledgement

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







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