RFC 4267

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

📅 published November 2005, from ietf

RFC 4267: The W3C Speech Interface Framework Media Types ✨

Okay bestie, so this is RFC 4267 🎀 and the full title is The W3C Speech Interface Framework Media Types, which covers application/voicexml+xml, application/ssml+xml, application/srgs, application/srgs+xml, application/ccxml+xml, and application/pls+xml. The author is M. Froumentin from the W3C 💅. It's Informational (so it's giving "here's some info," not a standard 🧚), and it's dated November 2005 🍓. The header doesn't list anything it obsoletes or updates, so there's nothing to report there 🙈.

Status of This Memo

This memo gives info to the Internet community. It does not specify an Internet standard of any kind 💜. Distribution of this memo is unlimited ✨.

Copyright (C) The Internet Society (2005) 🦋.

Abstract

This doc defines the media types for the languages of the W3C Speech Interface Framework 🎤. These were designed by the Voice Browser Working Group and cover 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

   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 🌸

Okay so this spec defines the media types for VoiceXML, SSML, SRGS, CCXML, and PLS, which are all the specs in the W3C Speech Interface Framework 🎀.

VoiceXML ([VoiceXML2.0]) is an Extensible Markup Language (XML) made for building audio dialogs. These dialogs can have synthesized speech, digitized audio, recognition of spoken and DTMF key input, recording of spoken input, telephony, and mixed initiative conversations 📞. The media type it gets in this doc is application/voicexml+xml 💖.

SSML is an XML-based markup language that helps generate synthetic speech in Web and other apps 🔊. Its whole job is giving authors of synthesizable content a standard way to control things like pronunciation, volume, pitch, and rate, across different synthesis-capable platforms 🧚. Its media type here is application/ssml+xml ✨.

SRGS defines syntax for grammars used in speech recognition, so developers can say exactly which words and patterns of words a recognizer should listen for 👂. The syntax comes in two forms, an Augmented BNF (ABNF) Form and an XML Form 💅. The media types are application/srgs and application/srgs+xml 🦋.

CCXML (the Call Control EXtensible Markup Language) is an XML designed to give telephony call control support to dialog systems, like VoiceXML ☎️. Its media type is application/ccxml+xml 🌈.

PLS defines an XML syntax for pronunciation lexicons, which speech recognition and speech synthesis engines use in voice browser applications 🎤. Its media type is application/pls+xml 💜.

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

Here's the registration info 📝.

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 one has the exact same semantics as the charset parameter of the application/xml media type, as specified in RFC 3023 [RFC3023] 🌸.

2.1. Encoding Considerations

Same as 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

These are the specs that get published with these media types 📚:

  • 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]
  • Pronunciation Lexicon Specification (PLS) Version 1.0 [PLS]

2.4. Applications that Use These Media Types

Lots of different W3C Speech Interface Framework implementations use these media types 🙌.

2.5. Security Considerations

Okay, this part is seriously important, so pay attention 🚨.

Several instructions in the cited specs can make arbitrary Uniform Resource Identifiers (URIs) get dereferenced 😳. In that case, the security issues of [RFC3986], section 7, should be considered.

Also, because these specs are extensible, the registered media types might describe content with security implications beyond what's described here 💀. But if the processor follows only the normative semantics of the specs, that content gets ignored 🛡️. Security issues would only potentially pop up if the processor recognizes and processes the extra content, or if further processing of that content gets dispatched to other processors 👀. And if that happens, those issues fall outside the domain of this registration document 🙈.

2.6. Additional Information

2.6.1. Magic Numbers

No byte sequences can be counted on to always be there, but XML MIME entities in ASCII-compatible charsets (including UTF-8) often start with the hexadecimal bytes 3C 3F 78 6D 6C ("<?xml") 🔍. Ones in UTF-16 often start with either 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. Those are the Byte Order Mark (BOM) followed by "<?xml" 🧠. For more info, 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

2.6.3. Fragment Identifiers

Same as 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 specs are a work product of the World Wide Web Consortium's Voice Browser Working Group 🏆. The W3C has change control over these specs 👑.

3.6.6 is up next, so picking up right where we left off, bestie 💅🎀

3.6.6. Change Controller ✨

okay so the SRGS spec is a work product of the World Wide Web Consortium's Voice Browser Working Group 🌸 and the W3C is the one with change control over it. so if anyone wants to change SRGS, that's their call 👑

4. IANA Considerations 🦋

okay so this document registers six new MIME media types 💖, and the details for each one live in Section 2 and Section 3. no cap, it's all there 🫶

5. Normative References 📚

these are the docs the spec leans on, the whole foundation, iykyk 💜

Author's Address 🖋️

Max Froumentin World Wide Web Consortium

EMail: mf@w3.org

Copyright (C) The Internet Society (2005).

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.

This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.

Intellectual Property 🔥

okay so the IETF takes no position on whether any IPR claims apply to the tech in this doc, or whether licenses are available, and it hasn't independently gone hunting for any either 🙈 the procedures for rights in RFCs are in BCP 78 and BCP 79.

copies of IPR disclosures made to the IETF Secretariat, plus any assurances of licenses, or the results of attempts to get a general license for implementers or users, can be found in the IETF online IPR repository at http://www.ietf.org/ipr.

the IETF also invites anyone to tell it about copyrights, patents, patent applications, or other proprietary rights that might cover technology needed to implement this standard. send that info to ietf-ipr@ietf.org 💌

Acknowledgement 🌷

funding for the RFC Editor function is currently provided by the Internet Society 💜

📦 where this page comes from