Network Working Group A. Melnikov Internet-Draft Isode Ltd Intended status: Standards Track March 7, 2009 Expires: September 8, 2009 Conversion parameters for IMAP CONVERT draft-melnikov-lemonade-convert-params-03.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. 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. This Internet-Draft will expire on September 8, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Melnikov Expires September 8, 2009 [Page 1] Internet-Draft IMAP CONVERT parameters March 2009 Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract This is a companion document to the IMAP CONVERT (RFC 5259) extension defined by the Lemonade Working Group. It defines additional conversion parameters for conversions of images, audio, video and textual body parts. It also demonstrates additional CONVERT usage scenarios. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Additional conversion parameters applicable to multiple MIME types . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Additional conversion parameters for image and video conversions . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Additional conversion parameters for conversions to text . . . 3 5. Additional conversion parameters for audio and video conversions . . . . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1. Normative References . . . . . . . . . . . . . . . . . . . 13 9.2. Informative References . . . . . . . . . . . . . . . . . . 13 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14 Melnikov Expires September 8, 2009 [Page 2] Internet-Draft IMAP CONVERT parameters March 2009 1. Requirements notation 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 [RFC2119]. In examples, "C:" and "S:" indicate lines sent by the client and server respectively. If a single "C:" or "S:" label applies to multiple lines, then the line breaks between those lines are for editorial clarity only and are not part of the actual protocol exchange. The five characters [...] means that something has been elided. [[anchor2: Editorial comments and questions are marked like this.]] 2. Additional conversion parameters applicable to multiple MIME types The sizeLimit defines the maximum size (in bytes) of the converted body part. It can be used with any conversion (including the "default conversion"). 3. Additional conversion parameters for image and video conversions Width and heigth of the resulting image can be specified using using the PIX-X and PIX-Y parameters defined in [DISPLAY-FEATURES]. If only one of the parameters is specified, the aspect ratio of the resulting image MUST be maintained. Number of different colors per image pixel (depth) can be controlled by the "color-levels" conversion parameter [DISPLAY-FEATURES]. This would typically be combined with the "color" conversion parameter [DISPLAY-FEATURES], which controls color encoding scheme, such as Mapped (palette or otherwise mapped color), Grey (grey-scale only) or Full (full continuous-tone color) 4. Additional conversion parameters for conversions to text The FORMAT conversion parameter can be used when converting a body part to TEXT/PLAIN. It can contain one of two values: "FLOWED" or "FIXED". When this parameter is not specified the default is "FIXED". This parameter is the most useful when converting from TEXT/HTML. See [RFC3676] for more details on the exact meaning of this conversion parameter. The ExifData conversion parameter can be used when extracting Exif Melnikov Expires September 8, 2009 [Page 3] Internet-Draft IMAP CONVERT parameters March 2009 information in textual format, i.e. when converting a JPEG image to TEXT/PLAIN. It can contain one of two values: "TRUE" or "FALSE". When this parameter is not specified the default value is "FALSE". The resulting TEXT/PLAIN body part is similar in format to the header field section of an email message [RFC5322]. Each header field name is as defined in section 4.6 (4.6.4 D and 4.6.6) of [EXIF] and each value is UTF-8 representation of the corresponding value. 5. Additional conversion parameters for audio and video conversions A conversion may change codec bitrate by specifying the "bitrate" conversion parameter, which is a non-negative integer specifying bits per second. The "encoding-method" conversion parameter can control whether fixed bitrate or variable bitrate encoding is used. It might have one of the two values: "FBR" (for fixed bit rate) or "VBR" (for variable bit rate). For variable bit rate encodings the "min-bit- rate" parameter can also be specified. Its value is a non-negative integer specifying the minimum bits per second. The "frameRate" conversion parameter can specify the maximum frame rate in frames per second, expressed as a rational (>0) number, for example "49/2". 6. IANA Considerations IANA is requested to add the following registrations to the registry established by [MEDIAFEAT-REG]. To: "Media feature tags mailing list" Subject: Registration of media feature tag sizeLimit Media feature tag name: sizeLimit ASN.1 identifier associated with feature tag: New assignment by IANA Summary of the media feature indicated by this feature tag: The sizeLimit defines the maximum size (in bytes) of the converted body part. It allows a client to control resulting size of a body part conversion using IMAP CONVERT [CONVERT]. This feature tag can be used with any conversion (including the "default conversion" [CONVERT]). Melnikov Expires September 8, 2009 [Page 4] Internet-Draft IMAP CONVERT parameters March 2009 Values appropriate for use with this feature tag: Signed Integer (only positive values are allowed) The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: IMAP CONVERT extension [CONVERT] Examples of typical use: C: b001 CONVERT 2 BINARY[3 ("image/jpeg" ("sizeLimit" "16384"))] Related standards or documents: [CONVERT] Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms: None Interoperability considerations: None Security considerations: None Additional information: None Name(s) & email address(es) of person(s) to contact for further information: Alexey Melnikov Intended usage: COMMON Author/Change controller: IETF Requested IANA publication delay: None Other information: None To: "Media feature tags mailing list" Subject: Registration of media feature tag FORMAT Media feature tag name: FORMAT Melnikov Expires September 8, 2009 [Page 5] Internet-Draft IMAP CONVERT parameters March 2009 ASN.1 identifier associated with feature tag: New assignment by IANA Summary of the media feature indicated by this feature tag: The FORMAT media feature can be used when converting a body part to TEXT/PLAIN media type. See [RFC3676] for more details on the exact meaning of this media feature. Values appropriate for use with this feature tag: Token (It can contain one of two values: "FLOWED" or "FIXED". When this parameter is not specified the default is "FIXED".) The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: IMAP CONVERT extension [CONVERT] Examples of typical use: C: b001 CONVERT 2 BINARY[3 ("text/plain" ("format" "flowed"))] Related standards or documents: [CONVERT] Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms: None Interoperability considerations: None Security considerations: None Additional information: None Name(s) & email address(es) of person(s) to contact for further information: Alexey Melnikov Intended usage: COMMON Author/Change controller: IETF Requested IANA publication delay: None Melnikov Expires September 8, 2009 [Page 6] Internet-Draft IMAP CONVERT parameters March 2009 Other information: This parameter is the most useful when converting from TEXT/HTML. To: "Media feature tags mailing list" Subject: Registration of media feature tag ExifData Media feature tag name: ExifData ASN.1 identifier associated with feature tag: New assignment by IANA Summary of the media feature indicated by this feature tag: The ExifData media feature can be used for extracting Exif information in textual format, i.e. when converting a JPEG image to TEXT/PLAIN. The resulting TEXT/PLAIN body part is similar in format to the header field section of an email message [RFC5322]. Each header field name is as defined in section 4.6 (4.6.4 D and 4.6.6) of [EXIF] and each value is UTF-8 representation of the corresponding value. Values appropriate for use with this feature tag: Boolean (When this parameter is not specified the default value is "FALSE".) The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: IMAP CONVERT extension [CONVERT] Examples of typical use: C: b001 CONVERT 2 BINARY[3 ("text/plain" ("ExifData" "TRUE"))] Related standards or documents: [CONVERT] Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms: None Interoperability considerations: None Security considerations: None Melnikov Expires September 8, 2009 [Page 7] Internet-Draft IMAP CONVERT parameters March 2009 Additional information: None Name(s) & email address(es) of person(s) to contact for further information: Alexey Melnikov Intended usage: COMMON Author/Change controller: IETF Requested IANA publication delay: None Other information: None To: "Media feature tags mailing list" Subject: Registration of media feature tag bitrate Media feature tag name: bitrate ASN.1 identifier associated with feature tag: New assignment by IANA Summary of the media feature indicated by this feature tag: An IMAP CONVERT conversion may change codec bitrate by specifying the "bitrate" conversion parameter, which is a non-negative integer specifying bits per second. Values appropriate for use with this feature tag: Signed Integer (only positive values are allowed) The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: IMAP CONVERT extension [CONVERT] Examples of typical use: C: b001 CONVERT 2 BINARY[3 ("AUDIO/G719" ("bitrate" "32768"))] Related standards or documents: [CONVERT] Melnikov Expires September 8, 2009 [Page 8] Internet-Draft IMAP CONVERT parameters March 2009 Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms: None Interoperability considerations: None Security considerations: None Additional information: None Name(s) & email address(es) of person(s) to contact for further information: Alexey Melnikov Intended usage: COMMON Author/Change controller: IETF Requested IANA publication delay: None Other information: None To: "Media feature tags mailing list" Subject: Registration of media feature tag encoding-method Media feature tag name: encoding-method ASN.1 identifier associated with feature tag: New assignment by IANA Summary of the media feature indicated by this feature tag: The "encoding-method" media feature can control whether fixed bitrate or variable bitrate encoding is used. Values appropriate for use with this feature tag: Token ("FBR" (for fixed bit rate) or "VBR" (for variable bit rate). The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: IMAP CONVERT extension [CONVERT] Melnikov Expires September 8, 2009 [Page 9] Internet-Draft IMAP CONVERT parameters March 2009 Examples of typical use: Related standards or documents: [CONVERT] Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms: None Interoperability considerations: None Security considerations: None Additional information: None Name(s) & email address(es) of person(s) to contact for further information: Alexey Melnikov Intended usage: COMMON Author/Change controller: IETF Requested IANA publication delay: None Other information: None To: "Media feature tags mailing list" Subject: Registration of media feature tag min-bit-rate Media feature tag name: min-bit-rate ASN.1 identifier associated with feature tag: New assignment by IANA Summary of the media feature indicated by this feature tag: For variable bit rate encodings The "min-bit-rate" media feature can be specified when "encoding-method" has value "VBR". It is a positive integer specifying bits per second. Melnikov Expires September 8, 2009 [Page 10] Internet-Draft IMAP CONVERT parameters March 2009 Values appropriate for use with this feature tag: Signed Integer (only positive values are allowed) The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: IMAP CONVERT extension [CONVERT] Examples of typical use: Related standards or documents: [CONVERT] Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms: None Interoperability considerations: None Security considerations: None Additional information: None Name(s) & email address(es) of person(s) to contact for further information: Alexey Melnikov Intended usage: COMMON Author/Change controller: IETF Requested IANA publication delay: None Other information: None To: "Media feature tags mailing list" Subject: Registration of media feature tag frameRate Media feature tag name: frameRate ASN.1 identifier associated with feature tag: New assignment by IANA Melnikov Expires September 8, 2009 [Page 11] Internet-Draft IMAP CONVERT parameters March 2009 Summary of the media feature indicated by this feature tag: The "frameRate" media feature can specify the maximum frame rate in frames per second, expressed as a rational (>0) number, for example "49/2". Values appropriate for use with this feature tag: Rational number The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: IMAP CONVERT extension [CONVERT] Examples of typical use: C: b001 CONVERT 2 BINARY[3 ("VIDEO/MP4" ("frameRate" "49/2"))] Related standards or documents: [CONVERT] Considerations particular to use in individual applications, protocols, services, or negotiation mechanisms: None Interoperability considerations: None Security considerations: None Additional information: None Name(s) & email address(es) of person(s) to contact for further information: Alexey Melnikov Intended usage: COMMON Author/Change controller: IETF Requested IANA publication delay: None Other information: None Melnikov Expires September 8, 2009 [Page 12] Internet-Draft IMAP CONVERT parameters March 2009 7. Security Considerations [[anchor9: TBD]] 8. Acknowledgments This document was reviewed and discussed in the Lemonade WG. Special thanks to Zoltan Ordogh for comments on this document. 9. References 9.1. Normative References [ABNF] Crocker, D., Ed. and P. Overell, Ed., "Augmented BNF for Syntax Specifications: ABNF", RFC 5234, January 2008. [EXIF] Japan Electronics and Information Technology Industries Association, "Exchangeable image file format for digital still cameras: Exif Version 2.2", JEITIA 2.2, April 2002. [MEDIAFEAT-REG] Holtman, K., Mutz, A., and T. Hardie, "Media Feature Tag Registration Procedure", BCP 31, RFC 2506, March 1999. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3676] Gellens, R., "The Text/Plain Format and DelSp Parameters", RFC 3676, February 2004. [RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, October 2008. 9.2. Informative References [CONVERT] Melnikov, A. and P. Coates, "Internet Message Access Protocol - CONVERT Extension", RFC 5259, July 2008. [DISPLAY-FEATURES] Masinter, L., Wing, D., Mutz, A., and K. Holtman, "Media Features for Display, Print, and Fax", RFC 2534, March 1999. [MIME-IMT] Freed, N. and N. Borenstein, "MIME (Multipurpose Internet Mail Extensions) Part Two: Media Types", RFC 2046, Melnikov Expires September 8, 2009 [Page 13] Internet-Draft IMAP CONVERT parameters March 2009 November 1996. Author's Address Alexey Melnikov Isode Ltd 5 Castle Business Village 36 Station Road Hampton, Middlesex TW12 2BX UK Email: Alexey.Melnikov@isode.com Melnikov Expires September 8, 2009 [Page 14]