Content Feature Schema for Internet Fax (V2)
RFC 2879

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Network Working Group                                             G. Klyne
Request for Comments: 2879                            Content Technologies
Obsoletes: 2531                                                L. McIntyre
Category: Standards Track                                Xerox Corporation
                                                               August 2000

              Content Feature Schema for Internet Fax (V2)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

   This document defines a content media feature schema for Internet
   fax.

   It is a profile of the media feature registration mechanisms [1,2,3]
   for use in performing capability identification between extended
   Internet fax systems [5].  It replaces and updates the feature schema
   defined in RFC 2531.

Table of Contents

   1. Introduction .............................................2
      1.1 Organization of this document ........................3
      1.2 Terminology and document conventions .................3
      1.3 Discussion of this document ..........................4
   2. Fax feature schema syntax ................................4
   3. Internet fax feature tags ................................4
      3.1 Image size ...........................................5
      3.2 Resolution ...........................................5
      3.3 Media type ...........................................6
      3.4 Paper Size ...........................................6
      3.5 Color capability .....................................7
      3.6 Color model ..........................................8
      3.7 Image coding ........................................11
      3.8 MRC mode ............................................12
   4. Examples ................................................13
      4.1 Simple mode Internet fax system  ....................13

Klyne & McIntyre            Standards Track                     [Page 1]
RFC 2879      Content Feature Schema for Internet Fax (V2)   August 2000

      4.2 High-end black-and-white Internet fax system.........14
      4.3 Grey-scale Internet fax system ......................14
      4.4 Full-color Internet fax system (JPEG only) ..........15
      4.5 Full-color Internet fax system (JPEG and JBIG) ......16
      4.6 Full-color Internet fax system (MRC) ................17
      4.7 Sender and receiver feature matching ................19
   5. IANA Considerations .....................................21
   6. Security Considerations .................................21
      6.1 Capability descriptions and mechanisms ..............21
      6.2 Specific threats ....................................21
   7. Acknowledgements ........................................22
   8. References ..............................................22
   9. Authors' Addresses ......................................24
   Appendix A: Feature registrations ..........................25
      A.1 Image size ..........................................25
      A.2 Resolution aspect ratio .............................27
      A.3 Color levels ........................................28
      A.4 Color space  ........................................30
      A.5 CIELAB color illuminant .............................33
      A.6 CIELAB color depth ..................................35
      A.7 CIELAB color gamut ..................................37
      A.8 Image file structure ................................39
      A.9 Image data coding ...................................41
      A.10 Image coding constraint ............................43
      A.11 JBIG stripe size .................................. 44
      A.12 Image interleave ...................................46
      A.13 Color subsampling ..................................47
      A.14 MRC availability and mode ..........................49
      A.15 MRC maximum stripe size ............................50
   Appendix B: TIFF mode descriptions .........................52
   Appendix C: Changes from RFC 2531 ..........................57
   Full Copyright Statement ...................................58

1. Introduction

   This document defines a content media feature schema for Internet
   fax.

   It is a profile of the media feature registration mechanisms [1,2,3]
   for use in performing capability identification between extended
   Internet fax systems [5].  It replaces and updates the feature schema
   defined in RFC 2531.

   The media feature description mechanisms do not describe any specific
   mechanisms for communicating capability information, but do presume