IETF Fax working group                                  Lloyd McIntyre
Internet draft                                       Xerox Corporation
Category: Work-in-progress                                Graham Klyne
                                            5GM/Content Technology Ltd
                                                     10 September 1999
                                                   Expires: March 2000


                  Internet fax T.30 Feature Mapping
             <draft-ietf-fax-feature-T30-mapping-02.txt>


Status of this memo

  This document is an Internet-Draft and is in full conformance with
  all provisions of Section 10 of RFC 2026.

  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.


  [[INTENDED STATUS: 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 1999.  All Rights Reserved.

Abstract

  This document describes how to map Group 3 fax capability
  identification bits, described in ITU T.30 [6], into the Internet
  fax feature schema described in "Content feature schema for
  Internet fax" [4].

  This is a companion to the fax feature schema document [4], which
  itself defines a profile of the media feature registration
  mechanisms [1,2,3], for use in performing capability identification
  between extended Internet fax systems [5].



McIntyre/Klyne             Work-in-progress                   [Page 1]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


Table of contents

  1. Introduction ............................................3
     1.1 Organization of this document                        3
     1.2 Terminology and document conventions                 4
     1.3 Discussion of this document                          4
  2. Combining feature tags ..................................4
     2.1 Relationship to Group 3 fax                          5
     2.2 Feature set descriptions                             5
     2.3 Examples                                             5
       2.3.1 Data resource example                            6
       2.3.2 Recipient capabilities example                   6
  3. Survey of media-related T.30 capability bits ............6
     3.1 DIS/DTC bit 15 (resolution)                          7
     3.2 DIS/DTC bit 16 (MR coding)                           7
     3.3 DIS/DTC bits 17,18 (width)                           7
     3.4 DIS/DTC bits 19,20 (length)                          7
     3.5 DIS/DTC bit 31 (MMR coding)                          8
     3.6 DIS/DTC bit 36 (JBIG multi-level coding)             8
     3.7 DIS/DTC bit 37 (plane interleave)                    8
     3.8 DIS/DTC bits 41,42,43 (resolution)                   8
     3.9 DIS/DTC bits 44,45 (preferred units)                 9
     3.10 DIS/DTC bit 68 (JPEG)                               9
     3.11 DIS/DTC bit 69 (colour)                             9
     3.12 DIS/DTC bit 71 (bits/sample)                        10
     3.13 DIS/DTC bit 73 (no subsampling)                     10
     3.14 DIS/DTC bit 74 (custom illuminant)                  10
     3.15 DIS/DTC bit 75 (custom gamut)                       10
     3.16 DIS/DTC bits 76,77 (paper size)                     11
     3.17 DIS/DTC bit 78 (JBIG bi-level coding)               11
     3.18 DIS/DTC bit 79 (JBIG stripe size)                   11
     3.19 DIS/DTC bit 92,93,94 (MRC maximum functional mode)  11
     3.20 DIS/DTC bit 95 (MRC stripe size)                    12
     3.21 DIS/DTC bit 97 (resolution)                         12
     3.22 DIS/DTC bit 98 (resolution)                         12
  4. Summary of T.30 capability dependencies .................12
     4.1 Image coding                                         12
       4.1.1 Bi-level coding                                  13
       4.1.2 Multi-level coding                               13
       4.1.3 MRC format                                       14
     4.2 Resolution and units                                 14
     4.3 Colour capabilities                                  16
     4.4 Document size                                        17
  5. Mapping T.30 capabilities to fax feature schema .........17
     5.1 Image coding                                         19
       5.1.1 Bi-level coding                                  19
       5.1.2 Multi-level coding                               20
       5.1.3 MRC format                                       21
     5.2 Resolution and units                                 22
     5.3 Colour capabilities                                  24
     5.4 Document size                                        25


McIntyre/Klyne             Work-in-progress                   [Page 2]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


  6. Examples ................................................26
     6.1 Common black-and-white fax machine                   26
       6.1.1 Corresponding Internet fax capabilities          29
     6.2 Full-featured color fax machine                      29
  7. Security considerations .................................33
  8. Acknowledgements ........................................34
  9. References ..............................................34
  10. Authors' addresses .....................................36
  Full copyright statement ...................................37
  Revision history ...........................................37


1. Introduction

  This document describes how to map Group 3 fax capability
  identification bits, described in ITU T.30 [6], into the Internet
  fax feature schema described in "Content feature schema for
  Internet fax" [4].

  This is a companion to the fax feature schema document [4], which
  itself defines a profile of the media feature registration
  mechanisms [1,2,3], for use in performing capability identification
  between extended Internet fax systems [5].

1.1 Organization of this document

  Section 2 introduces the mechanisms that combine feature tag
  constraints to describe complex recipient capabilities.

  Section 3 surveys Group 3 fax (T.30) capability bits that relate to
  media handling capabilities.

  Setion 4 describes the dependencies between Group 3 fax (T.30)
  capability bits.  These are presented in a decision table format
  [16] with descriptive text in place of the action bodies.

  Section 5 describes a formal mechanism for converting Group 3 fax
  (T.30) capability masks to fax feature schema statements.  The
  conversion process is driven by the decision tables introduced
  previously, using fax feature feature schema statements and
  combining rules in the action bodies.

  Section 6 presents an example of a Group 3 fax (T.30) capability
  mask, and uses the formal mechanism described previously to convert
  that into a corresponding fax feature schema statement.








McIntyre/Klyne             Work-in-progress                   [Page 3]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


1.2 Terminology and document conventions

  eifax system
            is used to describe any software, device or combination
            of these that conforms to the specification "Extended
            Facsimile Using Internet Mail" [5].

  Feature   is used as defined in [15].  (See also section 2 of this
            memo.)

  Feature tag
            is used as defined in [15].  (See also section 2.)

  Feature collection
            is used as defined in [2].  (See also section 2.)

  Feature set
            is used as defined in [2].  (See also section 2.)

1.3 Discussion of this document

  Discussion of this document should take place on the Internet fax
  mailing list hosted by the Internet Mail Consortium (IMC).  Please
  send comments regarding this document to:

      ietf-fax@imc.org

  To subscribe to this list, send a message with the body 'subscribe'
  to "ietf-fax-request@imc.org".

  To see what has gone on before you subscribed, please see the
  mailing list archive at:

      http://www.imc.org/ietf-fax/

2. Combining feature tags

  A fax document can be described by media features.  Any single
  media feature value can be thought of as just one component of a
  feature collection that describes some instance of a document (e.g.
  a printed fax, a displayed image, etc.).  Such a feature collection
  consists of a number of media feature tags (each per [1]) and
  associated feature values.










McIntyre/Klyne             Work-in-progress                   [Page 4]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


  A feature set contains a number of feature collections.  Thus, a
  feature set can describe a number of different fax document
  instances.  These can correspond to different treatments of a
  single document (e.g. different resolutions used for printing a
  given fax), a number of different documents subjected to a common
  treatment (e.g. the range of different images that can be rendered
  on a given display), or some combination of these (see examples
  below).

  Thus, a description of a feature set can describe the rendering
  requirements of a fax document or the capabilities of a receiving
  eifax system.

2.1 Relationship to Group 3 fax

  A "feature tag" can be compared with a single bit in a T.30 DCS
  frame, describing a specific attribute of a specific fax document.

  A "feature collection" corresponds to a complete T.30 DCS frame,
  describing a range of attributes of a specific fax document.

  A "feature set" corresponds to a DIS or DTC frame, describing the
  range of document attributes that can be accepted by a given fax
  machine.

  Within T.30 DIS/DTC frames, dependencies between the various
  capabilities are implicit in the definitions of the capabilities.
  E.g. multi-level coding (DIS/DTC bit 68) requires support for
  200*200dpi resolution (DIS/DTC bit 15).  In the feature set
  description framework used by eifax systems [1,2,3,4] such
  dependencies between different features are expressed explicitly.
  Later sections of this memo describe how the implicit dependencies
  of T.30 are expressed using the media feature set notation.

2.2 Feature set descriptions

  The general approach to describing feature sets, described more
  fully in [2], is use functions ("predicates") that, when applied to
  a feature collection value, yield a Boolean value that is TRUE if
  the feature collection describes an acceptable fax document
  instance, otherwise FALSE.

                     P(F)
       P(F) = TRUE <- : -> P(F) = FALSE
                      :
           +----------:----------+  This box represents some
           |          :          |  universe of fax documents (F)
           | Included : Excluded |  from which some acceptable subset
           |          :          |  is selected by the predicate P.
           +----------:----------+
                      :


McIntyre/Klyne             Work-in-progress                   [Page 5]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


2.3 Examples

  In the examples below the following notation is used:

     (x ? y)             tests feature tag 'x' for some relationship
                         with value 'y'.

     (| p1 p2 ... pn )   represents the logical-OR of predicates 'p1',
                         'p2' up to 'pn'.

     (& p1 p2 ... pn )   represents the logical-AND of predicates
                         'p1', 'p2' up to 'pn'.

2.3.1 Data resource example

  The following expression uses the syntax of [2] to describe a data
  resource that can be displayed either:
  (a)  as a 750x500 pixel image using 15 colours, or
  (b)  at 150dpi on an A4 page.

     (| (& (pix-x=750) (pix-y=500) (color=15) )
        (& (dpi>=150) (papersize=A4) ) )

2.3.2 Recipient capabilities example

  The following expression describes a receiving system that has:
  (a)  a screen capable of displaying 640*480 pixels and 16 million
       colours (24 bits per pixel), 800*600 pixels and 64 thousand
       colours (16 bits per pixel) or 1024*768 pixels and 256 colours
       (8 bits per pixel), or
  (b)  a printer capable of rendering 300dpi on A4 paper.

     (| (& (| (& (pix-x<=640)  (pix-y<=480) (color<=16777216) )
              (& (pix-x<=800)  (pix-y<=600) (color<=65535) )
              (& (pix-x<=1024) (pix-y<=768) (color<=256) ) )
           (media=screen) )
        (& (dpi=300)
           (media=stationery) (papersize=A4) ) )

3. Survey of media-related T.30 capability bits

  The following sections refer to T.30 DIS/DTC bits identified and
  described in Table 2/T.30 and accompanying notes [6].  Bit numbers
  that are not referenced below are considered to be not related to
  media features, hence not relevant to the Internet fax feature
  schema.

       NOTE: some of the DIS/DTC bits identified below are
       documented in revisions of the T.30 specification that
       are not yet publicly available from the ITU.



McIntyre/Klyne             Work-in-progress                   [Page 6]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


3.1 DIS/DTC bit 15 (resolution)

  All Group 3 fax systems are required to support a basic resolution
  of 200*100dpi (dots per inch) or 8*3.85dpmm (dots per millimetre).

  Setting this bit indicates additional support for 200*200dpi or
  8*7.7dpmm.

  For multi-level images, 200*200dpi is the basic resolution, and
  this bit must be set.  The other basic resolution options apply to
  bi-level images only.

  See also: bits 44,45.

3.2 DIS/DTC bit 16 (MR coding)

  All Group 3 fax systems are required to support Modified Huffman
  (MH) 1-dimensional coding for bi-level images.  (A bi-level image
  is one with just two pixel states such as black and white, as
  opposed to a grey-scale or colour image.)

  Setting this bit indicates additional support for Modified Read
  (MR) 2-dimensional coding for bi-level images.

  Both MH and MR coding are described in ITU T.4 [7].

  See also: bits 31,78,79.

3.3 DIS/DTC bits 17,18 (width)

  All Group 3 fax systems are required to support 215mm paper width.
  These bits can be set to indicate additional support for 255mm and
  303mm paper widths.

  See also: bits 76,77.

3.4 DIS/DTC bits 19,20 (length)

  All Group 3 fax systems are required to support 297mm paper length.
  These bits can be set to indicate additional support for 364mm and
  unlimited paper lengths.

  See also: bits 76,77.










McIntyre/Klyne             Work-in-progress                   [Page 7]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


3.5 DIS/DTC bit 31 (MMR coding)

  Setting this bit indicates support for Modified Modified Read (MMR)
  2-dimensional coding for bi-level images, in addition to the
  required support for MH coding.

  MMR coding is described in ITU T.6 [8].

  See also: bits 16,78,79.

3.6 DIS/DTC bit 36 (JBIG multi-level coding)

  If multi-level images are to be handled, support for JPEG coding is
  required (i.e. bit 68 must be set).  Setting bit 36 indicates
  additional support for JBIG lossless coding of multi-level images.

  JBIG coding for multi-level images is described in ITU T.43 [10]
  and T.4 Annex G [7].

  See also: bits 68,69.

3.7 DIS/DTC bit 37 (plane interleave)

  Setting this bit indicates support for plane interleave for JBIG-
  coded multi-level images in addition to stripe interleave, which is
  standard for JBIG multi-level images.

  JBIG coding for multi-level images is described in ITU T.43 [10]
  and T.4 Annex G [7].

  See also: bit 36.

3.8 DIS/DTC bits 41,42,43 (resolution)

  Setting these bits indicates support for resolutions in addition to
  200*100dpi and 200*200dpi, or 8*3.85dpmm and 8*7.7dpmm.  (Or in
  addition to the basic 200*200dpi resoloution when using a multi-
  level image mode.)

  Bit 41 indicates support for 8*15.4dpmm bi-level images
  (independently of the settings of bits 44 and 45).

  Bit 42 indicates support for 300*300dpi bi-level images
  (independently of the settings of bits 44 and 45).  Also applies to
  multi-level images or MRC mask if bit 97 is set.

  Bit 43 indicates support for 400*400dpi and/or 16*15.4dpmm bi-level
  images, depending uppon the settings of bits 44 and 45.  Also
  applies to multi-level images or MRC mask if bit 97 is set.

  See also: bits 15,44,45,97.


McIntyre/Klyne             Work-in-progress                   [Page 8]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


3.9 DIS/DTC bits 44,45 (preferred units)

  These bits are used to indicate the preferred resolution units for
  received images.  Because the exact resolution and x/y pixel
  density measures in dpi or dpmm are slightly different, some image
  size and aspect ratio distortion may occur if the sender and
  receiver use different units.

  Even when sender and recipient have different preferred units,
  image transfer must be accomplished.  For most fax uses, the dpi
  and dpmm measurements are sufficiently close to each other that the
  difference is not noticed.

  The preferred units setting affects the detailed interpretation of
  the following resolutions:

               dpi       dpmm      (dpi equivalent)
               ---       ----
     Base      200*100   8*3.85    204*98
     Bit 15    200*200   8*7.7     204*196
     Bit 43    400*400   16*15.4   408*391

  But terminals are required to accept the inch- and metric- based
  measures given above as equivalent, distorting the image if
  necessary to accommodate the differences.

  See also: bits 15, 43

3.10 DIS/DTC bit 68 (JPEG)

  This bit indicates support for JPEG coding of multi-level images.

  JPEG coding for multi-level images is described in ITU T.81 [12]
  and T.4 Annex E [7].

  See also: bits 15,69,73

3.11 DIS/DTC bit 69 (colour)

  This bit indicates support for colour images, in addition to just
  grey-scale.

  Both grey-scale and colour require multi-level coding.  The
  difference is that grey is single component while colour is multi-
  component.

  See also: bits 36,68,73.






McIntyre/Klyne             Work-in-progress                   [Page 9]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


3.12 DIS/DTC bit 71 (bits/sample)

  Standard support for multi-level images uses 8 bits per sample.
  Setting this bit indicates additional support for 12 bits per
  sample.

  For a grey-scale multi-level image, there is just one sample per
  pixel, giving 256 or 4096 possible pixel values.  For a full colour
  multi-level image there are three samples per pixel, giving 256^3
  (16777216) or 4096^3 (6871946736) possible values.

  When related to a mapped colour image, bit 71 also affects the
  maximum number of entries in the mapping table:  when it is reset,
  up to 4096 different pixel values can be used;  when set, up to
  65536 different values can be used.

  See also: bit 68.

3.13 DIS/DTC bit 73 (no subsampling)

  Standard support for JPEG-coded multi-level images uses 4:1:1
  chrominance subsampling.  That is, for each 4 luminance samples in
  the image data there is a single chrominance sample.

  Setting this bit indicates that JPEG-coded colour images without
  subsampling can also be supported.  This is not applicable to JBIG
  coding (bit 36).

  See also: bits 68,69.

3.14 DIS/DTC bit 74 (custom illuminant)

  Standard support for multi-level images requires use of D50
  illuminant.  Setting this bit indicates that a custom illuminant
  also can be supported for multi-level images (both grey-scale and
  colour).  Details of the custom illuminant are contained in the
  image data.

  Use of a custom illuminant with multi-level images is described in
  ITU T.4 Annex E [7].

  See also: bits 36,68.

3.15 DIS/DTC bit 75 (custom gamut)

  Standard support for a default colour gamut is required for multi-
  level images.  Setting this bit indicates that a custom gamut also
  can be supported for multi-level images (both grey-scale and
  colour).  Details of the custom gamut are contained in the image
  data.



McIntyre/Klyne             Work-in-progress                  [Page 10]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


  The default gamut (L*=[0,100], a*=[-85, 85], b* = [-75, 125]), and
  use of a custom gamut with multi-level images is described in ITU
  T.42 [9] and T.4 Annex E [7].

  See also: bit 36,68.

3.16 DIS/DTC bits 76,77 (paper size)

  All Group 3 faxes are required to support A4 paper size.  These
  bits can be set to indicate additional support for North American
  letter and legal paper sizes.

  See also: bits 17,18,19,20.

3.17 DIS/DTC bit 78 (JBIG bi-level coding)

  Setting bit 78 indicates support for JBIG coding of bi-level images
  (using T.85 encoding rules), in addition to the required support
  for MH coding.

  JBIG coding of bi-level images is described in ITU T.85 [14].

  See also: bits 16,31,79.

3.18 DIS/DTC bit 79 (JBIG stripe size)

  Setting bit 79 (along with bit 78) indicates support for the 'LO'
  option with JBIG coded bi-level images.  Basic bi-level JBIG coding
  uses 128 lines per stripe;  the 'LO' option allows other stripe
  sizes to be used.

  The stripe size is used for all stripes except the last, which may
  have fewer lines than the indicated value.

  JBIG coding of bi-level images is described in ITU T.85 [14].

  See also: bits 16,31,78.

3.19 DIS/DTC bit 92,93,94 (MRC maximum functional mode)

  If these bits are all zero, then Mixed Raster Content (MRC) coding
  is not supported.  Otherwise, they represent a number in the range
  1-7 that indicates an MRC maximum functional mode.

  MRC coding of images is described in ITU T.44 [11] and T.4 Annex H
  [17].

  See also: bits 68,95.





McIntyre/Klyne             Work-in-progress                  [Page 11]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


3.20 DIS/DTC bit 95 (MRC stripe size)

  Standard support for MRC uses a maximum stripe size of 256 lines.
  When this bit is set, the maximum stripe size is a full page.

  This bit is meaningful only if bits 92-94 indicate an MRC coding
  capability.  MRC coding of images is described in ITU T.44 [11] and
  T.4 Annex H [17].

  See also: bits 92,93,94.

3.21 DIS/DTC bit 97 (resolution)

  Setting this bit indicates that the additional resolutions
  indicated by bits 42 and 43 may be used for multi-level images and
  any MRC mask layer.

  When this bit is set, bit 42 implies 300dpi and bit 43 implies
  400dpi for multi-level or MRC mask layer images (irrespective of
  the preferred units indicated by bits 44 and 45).

  See also: bits 42,43,68.

3.22 DIS/DTC bit 98 (resolution)

  Setting this bit indicates that the additional resolution
  100*100dpi may be used for multi-level images.

       NOTE: 100dpi is not used for bi-level images, including
       the MRC mask layer.

  See also: bit 36,68,92-94.

4. Summary of T.30 capability dependencies

  This section contains a number of decision tables that indicate the
  allowable combinations of T.30 DIS/DTC mask bits.

  Within the decision table bodies, the following symbols are use to
  indicate values of T.30 DIS/DTC bits:

     0  = bit set to '0'
     1  = bit set to '1'
     x  = don't care bit value: may be '0' or '1'
     *0 = bit must be '0' ('1' is invalid in given combination)
     *1 = bit must be '1' ('0' is invalid in given combination)
     #  = bits in row combined to form a numeric value

4.1 Image coding

  MH coding is required as a minimum for Group 3 fax operation.


McIntyre/Klyne             Work-in-progress                  [Page 12]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


4.1.1 Bi-level coding

<------- T.30 bits --------->
15|16|31|36|37|68|69|73|78|79||Description
--+--+--+--+--+--+--+--+--+--++---------------------------------------
 x| 0| 0|  |  |  |  |  | 0| 0||Compression = [MH]
 x| 1| 0|  |  |  |  |  | 0| 0||Compression = [MH,MR]
 x| 0| 1|  |  |  |  |  | 0| 0||Compression = [MH,MMR]
 x| 1| 1|  |  |  |  |  | 0| 0||Compression = [MH,MR,MMR]
 x| 0| 0|  |  |  |  |  | 1| 0||Compression = [MH,T.85]
 x| 1| 0|  |  |  |  |  | 1| 0||Compression = [MH,MR,T.85]
 x| 0| 1|  |  |  |  |  | 1| 0||Compression = [MH,MMR,T.85]
 x| 1| 1|  |  |  |  |  | 1| 0||Compression = [MH,MR,MMR,T.85]
 x| 0| 0|  |  |  |  |  |*1| 1||Compression = [MH,T.85,T.85LO]
 x| 1| 0|  |  |  |  |  |*1| 1||Compression = [MH,MR,T.85,T.85LO]
 x| 0| 1|  |  |  |  |  |*1| 1||Compression = [MH,MMR,T.85,T.85LO]
 x| 1| 1|  |  |  |  |  |*1| 1||Compression = [MH,MR,MMR,T.85,T.85LO]
  |  |  |  |  |  |  |  |  |  ||MH     = 1-D per T.4
  |  |  |  |  |  |  |  |  |  ||MR     = 2-D per T.4
  |  |  |  |  |  |  |  |  |  ||MMR    = 2-D per T.6
  |  |  |  |  |  |  |  |  |  ||T.85   = Basic JBIG per T.85
  |  |  |  |  |  |  |  |  |  ||T.85LO = Optional LO with T.85/JBIG
  |  |  |  |  |  |  |  |  |  ||(Basic JBIG is 128 lines/stripe;  LO
  |  |  |  |  |  |  |  |  |  || allows other stripe sizes to be used)
--+--+--+--+--+--+--+--+--+--++---------------------------------------

4.1.2 Multi-level coding

  Note: When 37, 69, 73, 79 and 95 are set to "1", the feature
  represented by "0" is also available.  Example: If plane interleave
  is available then stripe interleave is also available.

<------- T.30 bits --------->
15|16|31|36|37|68|69|73|78|79||Description
--+--+--+--+--+--+--+--+--+--++---------------------------------------
 x|  |  |*0| x| 0| x| x|  |  ||No grey or colour (no T.43 or JPEG)
*1|  |  | 0| x| 1| 0| x|  |  ||JPEG, grey scale only
*1|  |  | 0| x| 1| 1| 0|  |  ||JPEG, full colour, subsampling
*1|  |  | 0| x| 1| 1| 1|  |  ||JPEG, full colour, no subsampling
*1|  |  | 1| 0|*1| 0| x|  |  ||T.43, JPEG, grey only, stripe i/l
*1|  |  | 1| 1|*1| 0| x|  |  ||T.43, JPEG, grey only, plane i/l
*1|  |  | 1| 0|*1| 1| 0|  |  ||T.43, JPEG, colour, stripe i/l, s/s
*1|  |  | 1| 0|*1| 1| 1|  |  ||T.43, JPEG, colour, stripe i/l, no s/s
*1|  |  | 1| 1|*1| 1| 0|  |  ||T.43, JPEG, colour, plane i/l, s/s
*1|  |  | 1| 1|*1| 1| 1|  |  ||T.43, JPEG, colour, plane i/l, no s/s
  |  |  |  |  |  |  |  |  |  ||'s/s'    is 4:1:1 L*:a*:b* subsampling
  |  |  |  |  |  |  |  |  |  ||'No s/s' is 1:1:1 L*:a*:b* subsampling
  |  |  |  |  |  |  |  |  |  ||'stripe i/l' is stripe interleave
  |  |  |  |  |  |  |  |  |  ||'plane i/l'  is full-plane interleave
--+--+--+--+--+--+--+--+--+--++---------------------------------------



McIntyre/Klyne             Work-in-progress                  [Page 13]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


4.1.3 MRC format

  Multi-level coders, as indicated above, are used for foreground and
  background images within an MRC-format document.  Bi-level codes
  are used for the mask layer.

<---- T.30 bits ------>
15|92|93|94|95|  |  |  ||Description
--+--+--+--+--+--+--+--++---------------------------------------
 x| 0| 0| 0| x|  |  |  ||MRC not accepted
*1| #| #| #| 0|  |  |  ||MRC level, max strip 256 lines
*1| #| #| #| 1|  |  |  ||MRC level, max strip full page
  |  |  |  |  |  |  |  ||### is MRC performance level (1-7, per T.44)
--+--+--+--+--+--+--+--++---------------------------------------

4.2 Resolution and units

  Support for bi-level coding at least one of 200*100dpi or
  8*3.85dpmm is required in all cases for Group 3 fax conformance.
  For multi-level coders (colour/grey) and MRC mask layers the base
  resolution is 200*200dpi (i.e. bit 15 must be set).

  When multi-level coders (JPEG or T.43) or MRC are used, only inch-
  based square resolutions are available.  However, the base non-
  square resolution (i.e. 200x100dpi or 8x3.85dpmm) must still be
  available as a capability for use with the mandatory bi-level coder
  (MH).  Hence, any references to metric and non-square resolutions
  in the table below apply only to bi-level coders.

  When describing MRC capabilities, the complete set of usable
  resolutions is listed.  However, there are some restrictions on
  their use:  (a) 100dpi resolution can be used only with multi-level
  images, and (b) any multi-level image resolution is required to be
  an integral sub-multiple of the applicable mask resolution.

  In the following table:
     dpi  = dots per inch
     dpmm = dots per millimetre
  Preferred resolutions are indicated here, even though inch- or mm-
  based units must be accepted, according to the T.30 protocol [6].













McIntyre/Klyne             Work-in-progress                  [Page 14]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999



<------- T.30 bits ------>
15|41|42|43|44|45|68|97|98||Description
--+--+--+--+--+--+--+--+--++-----------------------------------------
 0|  |  | 0| x| x|  |  |  ||Resolution = base only
  |  |  |  |  |  |  |  |  ||
 1|  |  | 0| 0| 0|  |  |  ||Invalid
 1|  |  | 0| 0| 1|  |  |  ||Resolution = 8*3.85dpmm or 8*7.7dpmm
 1|  |  | 0| 1| 0|  |  |  ||Resolution = 200*100dpi or 200*200dpi
 1|  |  | 0| 1| 1|  |  |  ||Resolution = 8*3.85dpmm or 8*7.7dpmm
  |  |  |  |  |  |  |  |  ||        or   200*100dpi or 200*200dpi
  |  |  |  |  |  |  |  |  ||
 0|  |  | 1| 0| 0|  |  |  ||Invalid
 0|  |  | 1| 0| 1|  |  |  ||Resolution = 8*3.85dpmm or 16*15.4dpmm
 0|  |  | 1| 1| 0|  |  |  ||Resolution = 200*100dpi or 400*400dpi
 0|  |  | 1| 1| 1|  |  |  ||Resolution = 8*3.85dpmm or 16*15.4dpmm
  |  |  |  |  |  |  |  |  ||        or   200*100dpi or 400*400dpi
  |  |  |  |  |  |  |  |  ||
 1|  |  | 1| 0| 0|  |  |  ||Invalid
 1|  |  | 1| 0| 1|  |  |  ||Resolution = 8*3.85dpmm or 8*7.7dpmm
  |  |  |  |  |  |  |  |  ||        or   16*15.4dpmm
 1|  |  | 1| 1| 0|  |  |  ||Resolution = 200*100dpi or 200*200dpi
  |  |  |  |  |  |  |  |  ||        or   400*400dpi
 1|  |  | 1| 1| 1|  |  |  ||Resolution = 8*7.7dpmm  or 8*7.7dpmm
  |  |  |  |  |  |  |  |  ||        or   16*15.4dpmm
  |  |  |  |  |  |  |  |  ||        or   200*100dpi or 200*200dpi
  |  |  |  |  |  |  |  |  ||        or   400*400dpi
--+--+--+--+--+--+--+--+--++-----------------------------------------
  | 0|  |  |  |  |  |  |  ||Resolutions as above
  | 1|  |  |  |  |  |  |  ||Also supports 8*15.4dpmm (bi-level only)
  |  |  |  |  |  |  |  |  ||Independent of bits 44,45
--+--+--+--+--+--+--+--+--++-----------------------------------------
  |  | 0|  |  |  |  |  |  ||Resolutions as above
  |  | 1|  |  |  |  |  |  ||Also supports 300*300dpi
  |  |  |  |  |  |  |  |  ||Independent of bits 44,45
--+--+--+--+--+--+--+--+--++-----------------------------------------
  |  |  |  |  |  | x| 0|  ||Resolutions as above
  |  |  |  |  |  |*1| 1|  ||Also 300*300dpi or 400*400dpi (see below)
  |  |  |  |  |  |  |  |  ||(Applies colour, grey-scale or MRC mask)
  |  |  |  |  |  |  |  |  ||(Valid only when bit 42 or 43 is set.)
  |  |  |  |  |  |  |  |  ||(42 => 300dpi, 43=>400dpi)
--+--+--+--+--+--+--+--+--++-----------------------------------------
  |  |  |  |  |  | x|  | 0||Resolutions as above
  |  |  |  |  |  |*1|  | 1||Also 100*100dpi
  |  |  |  |  |  |  |  |  ||(Applies colour or grey-scale only)
  |  |  |  |  |  |  |  |  ||(Independent of bits 44,45)
--+--+--+--+--+--+--+--+--++-----------------------------------------






McIntyre/Klyne             Work-in-progress                  [Page 15]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


4.3 Colour capabilities

  Bit 68 (JPEG) is required for any colour/grey scale mode, and bit
  36 indicates additional T.43 capability.

<------- T.30 bits --->
36|68|69|71|74|75|  |  ||Description
--+--+--+--+--+--+--+--++-----------------------------------------
 0| 0| x|  |  |  |  |  ||No grey scale or colour
 x| 1| 0|  |  |  |  |  ||Grey scale only
 0| 1| 1|  |  |  |  |  ||Full colour capability (CIE L*a*b*)
 1|*1| 1|  |  |  |  |  ||Full and limited colour capability:
  |  |  |  |  |  |  |  || (CIE L*a*b*, palette, RGB 1 bit/colour
  |  |  |  |  |  |  |  ||  and CMY(K)1 bit/colour)
--+--+--+--+--+--+--+--++-----------------------------------------
  | 0|  | x|  |  |  |  ||
  | 1|  | 0|  |  |  |  ||8 bits/pixel and up to 4096 palette entries
  | 1|  | 1|  |  |  |  ||8 or 12 bits/pixel, 65536 palette entries
--+--+--+--+--+--+--+--++-----------------------------------------
  | 0|  |  | x|  |  |  ||
  | 1|  |  | 0|  |  |  ||CIE standard illuminant D50 (per T.42)
  | 1|  |  | 1|  |  |  ||Custom illuminants (definition provided)
--+--+--+--+--+--+--+--++-----------------------------------------
  | 0|  |  |  | x|  |  ||
  | 1|  |  |  | 0|  |  ||Default gamut (per T.42)
  | 1|  |  |  | 1|  |  ||Custom gamuts (definition provided)
--+--+--+--+--+--+--+--++-----------------------------------------


























McIntyre/Klyne             Work-in-progress                  [Page 16]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


4.4 Document size

  A4 width (215mm) is required as a minimum for Group 3 fax
  conformance.  A Group 3 fax machine must always be able to receive
  an A4 image.

<---- T.30 bits ------>
17|18|19|20|76|77|  |  ||Description
--+--+--+--+--+--+--+--++-----------------------------------------
 0| 0|  |  |  |  |  |  ||Width = 215mm
 1| 0|  |  |  |  |  |  ||Width = 215mm or 255mm
 0| 1|  |  |  |  |  |  ||Width = 215mm, 255mm or 303mm
 1| 1|  |  |  |  |  |  ||Invalid - interpret as (17=0,18=1)
  |  |  |  |  |  |  |  ||(measurements described as scan line length)
  |  |  |  |  |  |  |  ||(corresp. inch measurements: T.4 sect 2.2)
--+--+--+--+--+--+--+--++-----------------------------------------
  |  | 0| 0|  |  |  |  ||Length = 297mm (A4)
  |  | 1| 0|  |  |  |  ||Length = 297mm (A4) or 364mm (B4)
  |  | 0| 1|  |  |  |  ||Length = unlimited
  |  | 1| 1|  |  |  |  ||Invalid
--+--+--+--+--+--+--+--++-----------------------------------------
  |  |  |  | 0| 0|  |  ||Papersize = A4
  |  |  |  | 1| 0|  |  ||Papersize = A4 or NA-Letter
  |  |  |  | 0| 1|  |  ||Papersize = A4 or NA-Legal
  |  |  |  | 1| 1|  |  ||Papersize = A4 or NA-Letter or NA-Legal
  |  |  |  |  |  |  |  ||(These in addition to paper sizes implied
  |  |  |  |  |  |  |  || by bits 17-20 above)
--+--+--+--+--+--+--+--++-----------------------------------------

5. Mapping T.30 capabilities to fax feature schema

  This section follows the structure of the previous section, except
  that the decision tables are restated with feature set expression
  mappings in the action stub.  The feature set expressions use media
  feature tags presented in "Content feature schema for Internet fax"
  [4].

  To construct a feature set expression corresponding to a collection
  of DIS frame bits:

  o  Compare the DIS bits with each decision table in the following
     sections (5.1 to 5.4).  Some decision tables consist of a number
     of sub-tables separated by horizontal lines.

  o  The DIS bits will match exactly one row from each table or sub-
     table:  collect the corresponding feature set expression from the
     action stub (the right hand column of the table).






McIntyre/Klyne             Work-in-progress                  [Page 17]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


  o  In the case of the table in section 5.2, which consists of
     several sub-tables, combine the feature set expressions from each
     sub-table with a logical-OR:  (| s1 s2 ... sn ), where 's1', 's2'
     etc. are the feature set expressions selected from each sub-
     table.  In this way, a single feature set expression is obtained
     for the table.

  o  In the case of the tables in sections 5.3 and 5.4, combine the
     sub-table expressions with a logical-AND:  (& s1 s2 ... sn ).

  o  Combine the feature set expressions for each table as follows:

       (& (| T511 T512 ) T513 T52 T53 T54 )

     where:

     - T511 is the feature set expression obtained from the table in
       section 5.1.1

     - T512 is obtained from the table in section 5.1.2

     - T513 is obtained from the table in section 5.1.3

     - T52 is obtained from the table in section 5.2

     - T53 is obtained from the table in section 5.3

     - T54 is obtained from the table in section 5.4

  The resulting expression is the feature set expression
  corresponding to the DIS bits given.  Remember that there may be
  other capabilities not expressed by the DIS bits that should be
  incorporated into the final feature expression (e.g. TIFF image
  file structure).

  To do the reverse transformation, match the feature set to each row
  of each decision table using the matching algorithm in RFC 2533
  [2], and OR together the DIS bit masks for each row whose feature
  set expression is completely contained by (i.e. is a subset of)
  that given (where the bit value in a table is 'x', use '0').

  A feature set A is completely contained by B if the feature set
  match of A and B (obtained by applying the feature set matching
  algorithm in [2]) is equal to A.









McIntyre/Klyne             Work-in-progress                  [Page 18]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


5.1 Image coding

5.1.1 Bi-level coding

<------- T.30 bits --------->
15|16|31|36|37|68|69|73|78|79||Feature set expression
--+--+--+--+--+--+--+--+--+--++---------------------------------------
 x| 0| 0|  |  |  |  |  | 0| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH]) )
 x| 1| 0|  |  |  |  |  | 0| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MR])
 x| 0| 1|  |  |  |  |  | 0| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MMR])
 x| 1| 1|  |  |  |  |  | 0| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MR,MMR])
 x| 0| 0|  |  |  |  |  | 1| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size=128) )
 x| 1| 0|  |  |  |  |  | 1| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MR,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size=128) )
 x| 0| 1|  |  |  |  |  | 1| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MMR,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size=128) )
 x| 1| 1|  |  |  |  |  | 1| 0||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MR,MMR,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size=128) )
 x| 0| 0|  |  |  |  |  |*1| 1||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size>=0) )
 x| 1| 0|  |  |  |  |  |*1| 1||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MR,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size>=0) )
 x| 0| 1|  |  |  |  |  |*1| 1||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MMR,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size>=0) )
 x| 1| 1|  |  |  |  |  |*1| 1||(& (color=binary)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[MH,MR,MMR,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JBIG-T85)
  |  |  |  |  |  |  |  |  |  ||   (JBIG-stripe-size>=0) )
--+--+--+--+--+--+--+--+--+--++---------------------------------------





McIntyre/Klyne             Work-in-progress                  [Page 19]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


5.1.2 Multi-level coding

<------- T.30 bits --------->
15|16|31|36|37|68|69|73|78|79||Feature set expression
--+--+--+--+--+--+--+--+--+--++---------------------------------------
 x|  |  |*0| x| 0| x| x|  |  ||
*1|  |  | 0| x| 1| 0| x|  |  ||(& (color=grey)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=JPEG)
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JPEG-T4E) )
*1|  |  | 0| x| 1| 1| 0|  |  ||(& (color=[grey,full])
  |  |  |  |  |  |  |  |  |  ||   (image-coding=JPEG)
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JPEG-T4E)
  |  |  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  |  |  ||      (color-subsampling="4:1:1") ) )
*1|  |  | 0| x| 1| 1| 1|  |  ||(& (color=[grey,full])
  |  |  |  |  |  |  |  |  |  ||   (image-coding=JPEG)
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=JPEG-T4E)
  |  |  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  |  |  ||      (color-subsampling=
  |  |  |  |  |  |  |  |  |  ||       ["1:1:1","4:1:1"]) ) )
*1|  |  | 1| 0|*1| 0| x|  |  ||(& (color=grey)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[JPEG,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=
  |  |  |  |  |  |  |  |  |  ||    [JPEG-T4E,JBIG-T43])
  |  |  |  |  |  |  |  |  |  ||   (image-interleave=stripe) )
*1|  |  | 1| 1|*1| 0| x|  |  ||(& (color=grey)
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[JPEG,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=
  |  |  |  |  |  |  |  |  |  ||    [JPEG-T4E,JBIG-T43])
  |  |  |  |  |  |  |  |  |  ||   (image-interleave=[stripe,plane]) )
*1|  |  | 1| 0|*1| 1| 0|  |  ||(& (color=[limited,mapped,grey,full])
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[JPEG,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=
  |  |  |  |  |  |  |  |  |  ||    [JPEG-T4E,JBIG-T43])
  |  |  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  |  |  ||      (color-subsampling="4:1:1"]) )
  |  |  |  |  |  |  |  |  |  ||   (image-interleave=stripe) )
*1|  |  | 1| 0|*1| 1| 1|  |  ||(& (color=[limited,mapped,grey,full])
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[JPEG,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=
  |  |  |  |  |  |  |  |  |  ||    [JPEG-T4E,JBIG-T43])
  |  |  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  |  |  ||      (color-subsampling=
  |  |  |  |  |  |  |  |  |  ||       ["1:1:1","4:1:1"]) )
  |  |  |  |  |  |  |  |  |  ||   (image-interleave=stripe) )








McIntyre/Klyne             Work-in-progress                  [Page 20]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


*1|  |  | 1| 1|*1| 1| 0|  |  ||(& (color=[limited,mapped,grey,full])
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[JPEG,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=
  |  |  |  |  |  |  |  |  |  ||    [JPEG-T4E,JBIG-T43])
  |  |  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  |  |  ||      (color-subsampling="4:1:1"]) )
  |  |  |  |  |  |  |  |  |  ||   (image-interleave=[stripe,plane]) )
*1|  |  | 1| 1|*1| 1| 1|  |  ||(& (color=[limited,mapped,grey,full])
  |  |  |  |  |  |  |  |  |  ||   (image-coding=[JPEG,JBIG])
  |  |  |  |  |  |  |  |  |  ||   (image-coding-constraint=
  |  |  |  |  |  |  |  |  |  ||    [JPEG-T4E,JBIG-T43])
  |  |  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  |  |  ||      (image-coding=JPEG)
  |  |  |  |  |  |  |  |  |  ||      (color-subsampling=
  |  |  |  |  |  |  |  |  |  ||       ["1:1:1","4:1:1"]) )
  |  |  |  |  |  |  |  |  |  ||   (image-interleave=[stripe,plane]) )
--+--+--+--+--+--+--+--+--+--++---------------------------------------
15|16|31|36|37|68|69|73|78|79||
--+--+--+--+--+--+--+--+--+--++---------------------------------------

5.1.3 MRC format

<---- T.30 bits ------>
15|92|93|94|95|  |  |  ||Feature set expression
--+--+--+--+--+--+--+--++---------------------------------------
 x| 0| 0| 0| x|  |  |  ||(MRC-mode=0)
*1| #| #| #| 0|  |  |  ||(& (MRC-mode<=###)
  |  |  |  |  |  |  |  ||   (MRC-max-stripe-size=[0..256]) )
*1| #| #| #| 1|  |  |  ||(& (MRC-mode<=###)
  |  |  |  |  |  |  |  ||   (MRC-max-stripe-size>=0) )
--+--+--+--+--+--+--+--++---------------------------------------






















McIntyre/Klyne             Work-in-progress                  [Page 21]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


5.2 Resolution and units

<------- T.30 bits ------>
15|41|42|43|44|45|68|97|98||Feature set expression
--+--+--+--+--+--+--+--+--++-----------------------------------------
 0|  |  | 0|  |  |  |  |  ||(& (color=binary)
  |  |  |  |  |  |  |  |  ||   (| (& (dpi=200) (dpi-xyratio=200/100) )
  |  |  |  |  |  |  |  |  ||      (& (dpi=204)
  |  |  |  |  |  |  |  |  ||         (dpi-xyratio=204/98) ) ) )
  |  |  |  |  |  |  |  |  ||
 1|  |  | 0|  |  |  |  |  ||(| (& (color=binary)
  |  |  |  |  |  |  |  |  ||      (| (& (dpi=204)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=204/98) )
  |  |  |  |  |  |  |  |  ||         (& (dpi=204)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=204/196) )
  |  |  |  |  |  |  |  |  ||         (& (dpi=200)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=200/100) ) ) )
  |  |  |  |  |  |  |  |  ||   (& (dpi=200) (dpi-xyratio=1) ) )
 0|  |  | 1|  |  |  |  |  ||(| (& (color=binary)
  |  |  |  |  |  |  |  |  ||      (| (& (dpi=204)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=204/98) )
  |  |  |  |  |  |  |  |  ||         (& (dpi=408)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=408/391) )
  |  |  |  |  |  |  |  |  ||         (& (dpi=200)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=200/100) ) ) )
  |  |  |  |  |  |  |  |  ||   (& (dpi=400) (dpi-xyratio=1) ) )



























McIntyre/Klyne             Work-in-progress                  [Page 22]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


 1|  |  | 1|  |  |  |  |  ||(| (& (color=binary)
  |  |  |  |  |  |  |  |  ||      (| (& (dpi=204)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=204/98) )
  |  |  |  |  |  |  |  |  ||         (& (dpi=204)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=204/196) )
  |  |  |  |  |  |  |  |  ||         (& (dpi=408)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=408/391) )
  |  |  |  |  |  |  |  |  ||         (& (dpi=200)
  |  |  |  |  |  |  |  |  ||            (dpi-xyratio=200/100) ) ) )
  |  |  |  |  |  |  |  |  ||   (& (dpi=200) (dpi-xyratio=1) )
  |  |  |  |  |  |  |  |  ||   (& (dpi=400) (dpi-xyratio=1) ) )
--+--+--+--+--+--+--+--+--++-----------------------------------------
  | 0|  |  |  |  |  |  |  ||
  | 1|  |  |  |  |  |  |  ||(& (color=binary)
  |  |  |  |  |  |  |  |  ||   (dpi=204)
  |  |  |  |  |  |  |  |  ||   (dpi-xyratio=204/391) )
--+--+--+--+--+--+--+--+--++-----------------------------------------
  |  | 0|  |  |  |  |  |  ||
  |  | 1|  |  |  |  |  |  ||(& (dpi=300) (dpi-xyratio=1) )
--+--+--+--+--+--+--+--+--++-----------------------------------------
  |  | x| x|  |  | x| 0|  ||
  |  | x| 1|  |  |*1| 1|  ||(& (dpi=400) (dpi-xyratio=1) )
  |  |*1| 0|  |  |*1| 1|  ||
--+--+--+--+--+--+--+--+--++-----------------------------------------
  |  |  |  |  |  | x|  | 0||
  |  |  |  |  |  |*1|  | 1||(| (color=binary)
  |  |  |  |  |  |  |  |  ||   (& (color=[limited,mapped,grey,full])
  |  |  |  |  |  |  |  |  ||      (dpi=100) (dpi-xyratio=1) ) )
--+--+--+--+--+--+--+--+--++-----------------------------------------
15|41|42|43|44|45|68|97|98||
--+--+--+--+--+--+--+--+--++-----------------------------------------

  Note:  all numbers in media feature expressions are integer or
  rational values;  hence the rational number format (n/m) used here.

  Also note:  the prefered unit bits (44,45) are not tested here, as
  a Group 3 fax machine must accept and process either form of units
  for binary images.  All resolutions are expressed in dpi;  here are
  the metric unit equivalents:

  204  ~= (1728/215)*25.4  ~=  8.04dpmm expressed in dpi
  408  ~= (3456/215)*25.4  ~= 16.08dpmm expressed in dpi
   98  ~=  3.85*25.4       ~=  3.85dpmm expressed in dpi
  196  ~=  7.70*25.4       ~=  7.70dpmm expressed in dpi
  391  ~= 15.40*25.4       ~= 15.40dpmm expressed in dpi








McIntyre/Klyne             Work-in-progress                  [Page 23]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


5.3 Colour capabilities

<------- T.30 bits --->
36|68|69|71|74|75|  |  ||Feature set expression
--+--+--+--+--+--+--+--++-----------------------------------------
 0| 0| x|  |  |  |  |  ||
 x| 1| 0|  |  |  |  |  ||(| (color=binary)
  |  |  |  |  |  |  |  ||   (& (color=grey)
  |  |  |  |  |  |  |  ||      (color-space=CIELAB) ) )
 0| 1| 1|  |  |  |  |  ||(| (color=binary)
  |  |  |  |  |  |  |  ||   (& (color=[grey,full])
  |  |  |  |  |  |  |  ||      (color-space=CIELAB) ) )
 1|*1| 1|  |  |  |  |  ||(| (color=binary)
  |  |  |  |  |  |  |  ||   (& (color=limited)
  |  |  |  |  |  |  |  ||      (color-space=[Device-RGB,Device-CMY])
  |  |  |  |  |  |  |  ||      (color-levels<=8) )
  |  |  |  |  |  |  |  ||   (& (color=limited)
  |  |  |  |  |  |  |  ||      (color-space=Device-CMYK)
  |  |  |  |  |  |  |  ||      (color-levels<=16) )
  |  |  |  |  |  |  |  ||   (& (color=[mapped,grey,full])
  |  |  |  |  |  |  |  ||      (color-space=CIELAB) ) )
--+--+--+--+--+--+--+--++-----------------------------------------
  | 0|  | x|  |  |  |  ||
  | 1|  | 0|  |  |  |  ||(| (color=[binary,limited])
  |  |  |  |  |  |  |  ||   (& (color=mapped)
  |  |  |  |  |  |  |  ||      (color-levels<=4096) )
  |  |  |  |  |  |  |  ||   (& (color=grey)
  |  |  |  |  |  |  |  ||      (color-levels<=256) )
  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  ||      (color-levels<=16777216) ) )
  | 1|  | 1|  |  |  |  ||(| (color=[binary,limited])
  |  |  |  |  |  |  |  ||   (& (color=mapped)
  |  |  |  |  |  |  |  ||      (color-levels<=65536) )
  |  |  |  |  |  |  |  ||   (& (color=grey)
  |  |  |  |  |  |  |  ||      (color-levels<=4096) )
  |  |  |  |  |  |  |  ||   (& (color=full)
  |  |  |  |  |  |  |  ||      (color-levels<=68719476736) ) )
--+--+--+--+--+--+--+--++-----------------------------------------
  | 0|  |  | x|  |  |  ||
  | 1|  |  | 0|  |  |  ||(| (color=[binary,limited])
  |  |  |  |  |  |  |  ||   (& (color=[mapped,grey,full])
  |  |  |  |  |  |  |  ||      (color-illuminant=D50) ) )
  | 1|  |  | 1|  |  |  ||   -- Any color illuminant: D50 or custom
  |  |  |  |  |  |  |  ||   -- See note below
--+--+--+--+--+--+--+--++-----------------------------------------








McIntyre/Klyne             Work-in-progress                  [Page 24]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


  | 0|  |  |  | x|  |  ||
  | 1|  |  |  | 0|  |  ||(| (color=[binary,limited])
  |  |  |  |  |  |  |  ||   (& (color=grey)
  |  |  |  |  |  |  |  ||      (CIELAB-L-min>=0)
  |  |  |  |  |  |  |  ||      (CIELAB-L-max<=100) )
  |  |  |  |  |  |  |  ||   (& (color=[mapped,full])
  |  |  |  |  |  |  |  ||      (CIELAB-L-min>=0)
  |  |  |  |  |  |  |  ||      (CIELAB-L-max<=100)
  |  |  |  |  |  |  |  ||      (CIELAB-a-min>=-85)
  |  |  |  |  |  |  |  ||      (CIELAB-a-max<=85)
  |  |  |  |  |  |  |  ||      (CIELAB-b-min>=-75)
  |  |  |  |  |  |  |  ||      (CIELAB-b-max<=125) ) )
  | 1|  |  |  | 1|  |  ||   -- Any color gamut: default or custom
--+--+--+--+--+--+--+--++-----------------------------------------
36|68|69|71|74|75|  |  ||Feature set expression
--+--+--+--+--+--+--+--++-----------------------------------------

       NOTE: the above table assumes the registration of a
       feature tag for color illuminant, values of which are
       tokens that are the same as thosed described by ITU T.4
       [7], Annex E, section E.6.7.

5.4 Document size

  A4 width (215mm) is required as a minimum for Group 3 fax
  conformance.  A Group 3 fax machine must always be able to receive
  an A4 image.

<---- T.30 bits ------>
17|18|19|20|76|77|  |  ||Feature set expression
--+--+--+--+--+--+--+--++-----------------------------------------
 0| 0|  |  |  |  |  |  ||(Size-x <= 2150/254)
 1| 0|  |  |  |  |  |  ||(Size-x <= 2550/254)
 x| 1|  |  |  |  |  |  ||(Size-x <= 3030/254)
--+--+--+--+--+--+--+--++-----------------------------------------
  |  | 0| 0|  |  |  |  ||(Size-y <= 2970/254)
  |  | 1| 0|  |  |  |  ||(Size-y <= 3640/254)
  |  | 0| 1|  |  |  |  ||  -- unlimited
  |  | 1| 1|  |  |  |  ||  -- invalid
--+--+--+--+--+--+--+--++-----------------------------------------
  |  |  |  | 0| 0|  |  ||(Paper-size=A4)
  |  |  |  | 1| 0|  |  ||(Paper-size=[A4,Letter])
  |  |  |  | 0| 1|  |  ||(Paper-size=[A4,Legal])
  |  |  |  | 1| 1|  |  ||(Paper-size=[A4,Letter,Legal])
--+--+--+--+--+--+--+--++-----------------------------------------








McIntyre/Klyne             Work-in-progress                  [Page 25]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


6. Examples

       NOTE:  Although motivated by the requirements of eifax
       [5], this document is concerned with describing
       capabilities of Group 3 fax systems [6].  As such, the
       algorithms do not of themselves create equivalent
       Internet fax capability statements but, rather, they
       construct capability expressions that might be
       incorporated into those for eifax systems.

       This point is illustrated at the end of the first example
       below where subsection 6.1.1 has been added, which
       combines T.30 capabilities with an appropriate TIFF file
       format capability to yield an expression that might be
       used to describe an Internet fax system.

6.1 Common black-and-white fax machine

     DIS/DTC
     Bit No.   DIS/DTC bit description                 Value
     -------   -----------------------                 -----
     15        R8 x 7.7 lines/mm and/or                1
               200 x 200 pels/25.4 mm
     16        Two dimensional coding capability       1
     17,18     Recording width capabilities:           0,0
               Scan line length 215 mm + 1%
     19,20     Recording length capability:            01
               unlimited
     31        T.6 (MMR) coding capability             1
     36        T.43 (JBIG) coding capability           0
     37        Plane interleave                        0
     41        Resolution: 8x15.4 dpmm                 0
     42        Resolution: 300x300 dpi                 1
     43        Resolution: 16x15.4 dpmm and/or 400x400 0
               dpi
     68        JPEG coding: not supported              0
     69        Full color mode: not supported          0
     71        12 bits/pel component:  not supported   0
     73        No subsampling (1:1:1):  not supported  0
     74        Custom illuminant:  not supported       0
     75        Custom gamut range:  not supported      0
     76        North American Letter paper size        1
               (8.5"x11") capability
     77        North American Legal paper size         0
               (8.5"x14") capability:  not supported
     78        Single-progression sequential coding    0
               (T.85, bi-level JBIG) basic capability:
               not supported





McIntyre/Klyne             Work-in-progress                  [Page 26]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


     79        Single-progression sequential coding    0
               (T.85, bi-level JBIG) optional L0
               capability for other than 128
               lines/stripe:  not supported
     92,93,94  T.44 (Mixed Raster Content) mode:       0,0,0
               not supported
     95        Page length maximum stripe size for MRC 0
               coding:  not supported.
     97        Multi-level resolution 300x300dpi or    0
               400x400dpi:  not supported
     98        Multi-level resolution 100x100dpi:      0
               not supported

  Following the procedure in section 5, matching these DIS bits
  against the decision tables in setions 5.1 to 5.4, we get:

     5.1.1  [Bits 16,31,78,79 = 1,1,0,0]
              (& (color=binary) (image-coding=[MH,MR,MMR]) )
     5.1.2  [Bits 15,36,37,68,69,73 = 1,0,0,0,0,0]
              -- no capabilities
     5.1.3  [Bits 15,92,93,94,95 = 1,0,0,0,0]
              (MRC-mode=0)
     5.2    [Bits 15,43 = 1,0]
              (| (& (color=binary)
                    (| (& (dpi=204)
                          (dpi-xyratio=204/98) )
                       (& (dpi=204)
                          (dpi-xyratio=204/196) )
                       (& (dpi=200)
                          (dpi-xyratio=200/100) ) ) )
                 (& (dpi=200) (dpi-xyratio=1) ) )
            [Bit 41 = 0]
              -- no capabilities
            [Bit 42 = 1]
              (& (dpi=300) (dpi-xyratio=1) )
            [Bits 42,43,68,97 = 0,0,0,0]
              -- no capabilities
            [Bits 68,98 = 0,0]
              -- no capabilities
     5.3    [Bits 36,68,69 = 0,0,0]
              -- no capabilities
            [Bits 68,71 = 0,0]
              -- no capabilities
            [Bits 68,74 = 0,0]
              -- no capabilities
            [Bits 68,75 = 0,0]
              -- no capabilities






McIntyre/Klyne             Work-in-progress                  [Page 27]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


     5.4    [Bits 17,18 = 0,0]
              (size-x<=2150/254)
            [Bits 19,20 = 0,1]
              -- no capability constraint
            [Bits 76,77 = 1,0]
              (Paper-size=[A4,Letter])

  Combining these as indicated in section 5, we get the following.
  (The initial expression is constructed verbatim per the rules in
  the first part of section 5, even though it contains some
  redundancy.)

     (& (| (& (color=binary) (image-coding=[MH,MR,MMR]) ) )
        (MRC-mode=0)
        (| (| (& (color=binary)
                 (| (& (dpi=204) (dpi-xyratio=204/98)  )
                    (& (dpi=204) (dpi-xyratio=204/196) )
                    (& (dpi=200) (dpi-xyratio=200/100) ) ) )
              (& (dpi=200) (dpi-xyratio=1) ) )
           (& (dpi=300) (dpi-xyratio=1) ) )
        (& (size-x<=2150/254)
           (Paper-size=[A4,Letter]) ) )

  This in turn is simplified as follows.  Note that the expression
  '(& (| (& A B ) ) C ... )' simplifies to just '(& A B C ... )'.

     (& (color=binary)
        (image-coding=[MH,MR,MMR])
        (MRC-mode=0)
        (| (& (dpi=204) (dpi-xyratio=204/98)  )
           (& (dpi=204) (dpi-xyratio=204/196) )
           (& (dpi=200) (dpi-xyratio=200/100) )
           (& (dpi=200) (dpi-xyratio=1) )
           (& (dpi=300) (dpi-xyratio=1) ) )
        (size-x<=2150/254)
        (Paper-size=[A4,Letter]) )

















McIntyre/Klyne             Work-in-progress                  [Page 28]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


6.1.1 Corresponding Internet fax capabilities

  In the case of an Internet fax device, additional capabilities not
  described by the T.30 DIS frame should be included;  e.g. the
  supported TIFF file structure:

     (& (color=binary)
        (image-file-structure=[TIFF-Limited,TIFF-Minimal])
        (image-coding=[MH,MR,MMR])
        (MRC-mode=0)
        (| (& (dpi=204) (dpi-xyratio=204/98)  )
           (& (dpi=204) (dpi-xyratio=205/196) )
           (& (dpi=200) (dpi-xyratio=200/100) )
           (& (dpi=200) (dpi-xyratio=1) )
           (& (dpi=300) (dpi-xyratio=1) ) )
        (size-x<=2150/254)
        (Paper-size=[A4,Letter]) )

6.2 Full-featured color fax machine

     DIS/DTC
     Bit No.   DIS/DTC bit description                 Value
     -------   -----------------------                 -----
     15        R8 x 7.7 lines/mm and/or                1
               200 x 200 pels/25.4 mm
     16        Two dimensional coding capability       1
     17,18     Recording width capabilities:           0,0
               Scan line length 215 mm + 1%
     19,20     Recording length capability:            01
               unlimited
     31        T.6 (MMR) coding capability             1
     36        T.43 (JBIG) coding capability           0
     37        Plane interleave                        0
     41        Resolution: 8x15.4 dpmm                 1
     42        Resolution: 300x300 dpi                 0
     43        Resolution: 16x15.4 dpmm and/or 400x400 1
               dpi
     68        JPEG coding: supported                  1
     69        Full color mode: supported              1
     71        12 bits/pel component:  not supported   0
     73        No subsampling (1:1:1):  supported      1
     74        Custom illuminant:  not supported       0
     75        Custom gamut range:  not supported      0
     76        North American Letter paper size        1
               (8.5"x11") capability
     77        North American Legal paper size         0
               (8.5"x14") capability:  not supported






McIntyre/Klyne             Work-in-progress                  [Page 29]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


     78        Single-progression sequential coding    0
               (T.85, bi-level JBIG) basic capability:
               not supported
     79        Single-progression sequential coding    0
               (T.85, bi-level JBIG) optional L0
               capability for other than 128
               lines/stripe:  not supported
     92,93,94  T.44 (Mixed Raster Content) mode:       0,0,1
               mode 1 supported
     95        Page length maximum stripe size for MRC 1
               coding.
     97        Multi-level resolution 300x300dpi or    1
               400x400dpi:  supported
     98        Multi-level resolution 100x100dpi:      1
               supported

  Matching these DIS bits against the decision tables in setions 5.1
  to 5.4, we get:

     5.1.1  [Bits 16,31,78,79 = 1,1,0,0]
              (& (color=binary) (image-coding=[MH,MR,MMR]) )
     5.1.2  [Bits 15,36,37,68,69,73 = 1,0,0,1,1,1]
              (& (color=[grey,full])
                 (image-coding=JPEG)
                 (image-coding-constraint=JPEG-T4E)
                 (& (color=full)
                    (image-coding=JPEG)
                    (color-subsampling=["1:1:1","4:1:1"]) ) )
     5.1.3  [Bits 15,92,93,94,95 = 1,0,0,1,1]
              (& (MRC-mode<=1) (MRC-max-stripe-size>=0) )























McIntyre/Klyne             Work-in-progress                  [Page 30]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


     5.2    [Bits 15,43 = 1,1]
              (| (& (color=binary)
                    (| (& (dpi=204)
                          (dpi-xyratio=204/98) )
                       (& (dpi=204)
                          (dpi-xyratio=204/196) )
                       (& (dpi=408)
                          (dpi-xyratio=408/391) )
                       (& (dpi=200)
                          (dpi-xyratio=200/100) ) ) )
                 (& (dpi=200) (dpi-xyratio=1) )
                 (& (dpi=400) (dpi-xyratio=1) ) )
            [Bit 41 = 1]
              (& (color=binary)
                 (dpi=204) (dpi-xyratio=204/391) )
            [Bit 42 = 0]
              -- no capabilities
            [Bits 42,43,68,97 = 0,1,1,1]
              (& (dpi=400) (dpi-xyratio=1) )
            [Bits 68,98 = 1,1]
              (| (color=binary)
                 (& (color=[limited,mapped,grey,full])
                    (dpi=100) (dpi-xyratio=1) ) )
     5.3    [Bits 36,68,69 = 0,1,1]
              (| (color=binary)
                 (& (color=[grey,full])
                    (color-space=CIELAB) ) )
            [Bits 68,71 = 1,0]
              (| (color=[binary,limited])
                 (& (color=mapped)
                    (color-levels<=4096) )
                 (& (color=grey)
                    (color-levels<=256) )
                 (& (color=full)
                    (color-levels<=16777216) ) )
            [Bits 68,74 = 1,0]
              (| (color=[binary,limited])
                 (& (color=[mapped,grey,full])
                    (color-illuminant=D50) ) )
            [Bits 68,75 = 1,0]
              (| (color=[binary,limited])
                 (& (color=grey)
                    (CIELAB-L-min>=0)
                    (CIELAB-L-max<=100) )
                 (& (color=[mapped,full])
                    (CIELAB-L-min>=0)
                    (CIELAB-L-max<=100)
                    (CIELAB-a-min>=-85)
                    (CIELAB-a-max<=85)
                    (CIELAB-b-min>=-75)
                    (CIELAB-b-max<=125) ) )


McIntyre/Klyne             Work-in-progress                  [Page 31]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


     5.4    [Bits 17,18 = 0,0]
              (size-x<=2150/254)
            [Bits 19,20 = 0,1]
              -- no capability constraint
            [Bits 76,77 = 1,0]
              (Paper-size=[A4,Letter])

  Combining these as indicated in section 5, we get the following:

     (& (| (& (color=binary)
              (image-coding=[MH,MR,MMR]) )
           (& (color=[grey,full])
              (image-coding=JPEG)
              (image-coding-constraint=JPEG-T4E)
              (& (color=full)
                 (image-coding=JPEG)
                 (color-subsampling=["1:1:1","4:1:1"]) ) )
        (& (MRC-mode<=1) (MRC-max-stripe-size>=0) )
        (| (| (& (color=binary)
                 (| (& (dpi=204) (dpi-xyratio=204/98) )
                    (& (dpi=204) (dpi-xyratio=204/196) )
                    (& (dpi=408) (dpi-xyratio=408/391) )
                    (& (dpi=200) (dpi-xyratio=200/100) ) ) )
              (& (dpi=200) (dpi-xyratio=1) )
              (& (dpi=400) (dpi-xyratio=1) ) )
           (& (color=binary)
              (dpi=204) (dpi-xyratio=204/391) )
           (& (dpi=400) (dpi-xyratio=1) )
           (| (color=binary)
              (& (color=[limited,mapped,grey,full])
                 (dpi=100) (dpi-xyratio=1) ) ) )
        (& (| (color=binary)
              (& (color=[grey,full]) (color-space=CIELAB) ) )
           (| (color=[binary,limited])
              (& (color=mapped) (color-levels<=4096) )
              (& (color=grey) (color-levels<=256) )
              (& (color=full) (color-levels<=16777216) ) )
           (| (color=[binary,limited])
              (& (color=[mapped,grey,full]) (color-illuminant=D50) ) )
           (| (color=[binary,limited])
              (& (color=grey)
                 (CIELAB-L-min>=0)
                 (CIELAB-L-max<=100) )
              (& (color=[mapped,full])
                 (CIELAB-L-min>=0)
                 (CIELAB-L-max<=100)
                 (CIELAB-a-min>=-85)
                 (CIELAB-a-max<=85)
                 (CIELAB-b-min>=-75)
                 (CIELAB-b-max<=125) ) ) )
        (& (size-x<=2150/254)


McIntyre/Klyne             Work-in-progress                  [Page 32]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


           (Paper-size=[A4,Letter]) ) )

  This in turn simplifies to:

     (| (& (color=binary)
           (image-coding=[MH,MR,MMR])
           (MRC-mode<=1) (MRC-max-stripe-size>=0)
           (| (& (dpi=204) (dpi-xyratio=204/98) )
              (& (dpi=204) (dpi-xyratio=204/196) )
              (& (dpi=204) (dpi-xyratio=204/391) )
              (& (dpi=408) (dpi-xyratio=408/391) )
              (& (dpi=200) (dpi-xyratio=200/100) )
              (& (dpi=200) (dpi-xyratio=1) )
              (& (dpi=400) (dpi-xyratio=1) ) )
           (size-x<=2150/254)
           (Paper-size=[A4,Letter]) )
        (& (color=grey)
           (image-coding=JPEG)
           (image-coding-constraint=JPEG-T4E)
           (MRC-mode<=1) (MRC-max-stripe-size>=0)
           (dpi=[100,200,400]) (dpi-xyratio=1)
           (color-space=CIELAB)
           (color-levels<=256)
           (color-illuminant=D50)
           (CIELAB-L-min>=0)
           (CIELAB-L-max<=100)
           (size-x<=2150/254)
           (Paper-size=[A4,Letter]) )
        (& (color=full)
           (image-coding=JPEG)
           (image-coding-constraint=JPEG-T4E)
           (color-subsampling=["1:1:1","4:1:1"])
           (MRC-mode<=1) (MRC-max-stripe-size>=0)
           (dpi=[100,200,400]) (dpi-xyratio=1)
           (color-space=CIELAB)
           (color-levels<=16777216)
           (color-illuminant=D50)
           (CIELAB-L-min>=0)
           (CIELAB-L-max<=100)
           (CIELAB-a-min>=-85)
           (CIELAB-a-max<=85)
           (CIELAB-b-min>=-75)
           (CIELAB-b-max<=125)
           (size-x<=2150/254)
           (Paper-size=[A4,Letter]) ) )

7. Security considerations

  Security considerations are discussed in the fax feature schema
  description [4].  This memo is not believed to introduce any
  additional security concerns.


McIntyre/Klyne             Work-in-progress                  [Page 33]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


8. Acknowledgements

  The authors gratefully ackowledge the following persons who made
  comments on earlier versions of this memo:  Mr. Hiroshi Tamura and
  and Dr. Robert Buckley.

9. References

[1]  RFC 2506, "Media Feature Tag Registration Procedure"
     Koen Holtman, TUE
     Andrew Mutz, Hewlett-Packard
     Ted Hardie, NASA
     March 1999.

[2]  RFC 2533, "A syntax for describing media feature sets"
     Graham Klyne, 5GM/Content Technologies
     March 1999.

[3]  RFC 2534, "Media Features for Display, Print, and Fax"
     Larry Masinter, Xerox PARC
     Koen Holtman, TUE
     Andrew Mutz, Hewlett-Packard
     Dan Wing, Cisco Systems
     March 1999.

[4]  RFC 2531, "Content feature schema for Internet fax"
     Graham Klyne, 5GM/Content Technologies
     Lloyd McIntyre, Xerox Corporation
     March 1998.

[5]  RFC 2532, "Extended Facsimile Using Internet Mail"
     Larry Masinter, Xerox Corporation
     Dan Wing, Cisco Systems
     March 1999.

[6]  "Procedures for document facsimile transmission in the general
     switched telephone network"
     ITU-T Recommendation T.30 (1996), including Amendment 1 (1997),
     Amendment 2 (1997), Amendment 3 (1998) and Amendment 4 (1999)
     International Telecommunications Union

[7]  "Standardization of Group 3 facsimile terminals for document
     transmission"
     ITU-T Recommendation T.4 (1996), including Amendment 1 (1997),
     Amendment 2 (1997) and Amendment 3 (1999)
     International Telecommunications Union
     (Covers basic fax coding formats:  MH, MR;  Annex E deals with
     some color image related matters, including codes for optional
     custom illuminants.  Annex G deals with some aspects of JBIG
     encoding of multi-level images.)



McIntyre/Klyne             Work-in-progress                  [Page 34]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


[8]  "Facsimile coding schemes and coding control functions for Group
     4 facsimile apparatus"
     ITU Recommendation T.6
     International Telecommunications Union
     (Commonly referred to as the MMR standard; covers extended 2-D
     fax coding format)

[9]  "Continuous-tone colour representation method for facsimile"
     ITU-T Recommendation T.42 (1996)
     International Telecommunications Union
     (Covers custom illuminant, gamut)

[10] "Colour and gray-scale image representation using lossless coding
     scheme for facsimile"
     ITU-T Recommendation T.43 (1997)
     International Telecommunications Union
     (Covers JBIG for colour/grey images)

[11] "Mixed Raster Content (MRC)"
     ITU-T Recommendation T.44 (1999)
     International Telecommunications Union

[12] "Information technology - Digital compression and coding of
     continuous-tone still image - Requirements and guidelines"
     ITU-T Recommendation T.81 (1992) | ISO/IEC 10918-1:1993
     International Telecommunications Union
     (Commonly referred to as JPEG standard)

[13] "Information technology - Coded representation of picture and
     audio information - Progressive bi-level image compression"
     ITU-T Recommendation T.82 (1993) | ISO/IEC 11544:1993
     International Telecommunications Union
     (Commonly referred to as JBIG1 standard)

[14] "Application profile for Recommendation T.82 - Progressive bi-
     level image compression (JBIG1 coding scheme for facsimile
     apparatus)"
     ITU-T Recommendation T.85 (1995), including Amendment 1 (1996),
     Amendment 2 (1997) and Corrigendum 1 (1997)
     International Telecommunications Union
     (Covers bi-level JBIG)

[15] "Protocol-independent content negotiation framework"
     G. Klyne, 5GM/Content Technologies.
     Internet draft: <draft-ietf-conneg-requirements-02.txt>
     Work in progress, March 1999.







McIntyre/Klyne             Work-in-progress                  [Page 35]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


[16] "Programs from Decision Tables"
     E. Humbey
     Macdonald/American Elsevier computer monographs (19), 1973
     ISBN 0-444-19569-6/0-356-04126-3

     (This is an old title, and may not be still in print.  It
     contains a number of references to decision table articles
     published in Communications of the ACM:  August 1967, September
     1970, January 1966, November 1966, October 1968, January 1965,
     February 1964, June 1970, November 1965, June 1965, February
     1971.)

[17] "Mixed Raster Content (MRC) mode for G3 facsimile"
     ITU-T Recommendation T.4, Annex H (1999)
     International Telecommunications Union
     (Covers stripe size)

10. Authors' addresses

  Lloyd McIntyre
  Xerox Corporation
  Mailstop PAHV-121
  3400 Hillview Ave.
  Palo Alto, CA 94304 USA
  Telephone: +1-650-813-6762
  Facsimile: +1-650-845-2340
  E-mail: Lloyd.McIntyre@pahv.xerox.com

  Graham Klyne
  5th Generation Messaging Ltd.    Content Technologies Ltd.
  5 Watlington Street              Forum 1, Station Road
  Nettlebed                        Theale
  Henley-on-Thames, RG9 5AB        Reading, RG7 4RA
  United Kingdom                   United Kingdom.
  Telephone: +44 1491 641 641      +44 118 930 1300
  Facsimile: +44 1491 641 611      +44 118 930 1301
  E-mail: GK@ACM.ORG
















McIntyre/Klyne             Work-in-progress                  [Page 36]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


Full copyright statement

  Copyright (C) The Internet Society 1999.  All Rights Reserved.

  This document and translations of it may be copied and furnished to
  others, and derivative works that comment on or otherwise explain
  it or assist in its implementation may be prepared, copied,
  published and distributed, in whole or in part, without restriction
  of any kind, provided that the above copyright notice and this
  paragraph are included on all such copies and derivative works.
  However, this document itself may not be modified in any way, such
  as by removing the copyright notice or references to the Internet
  Society or other Internet organizations, except as needed for the
  purpose of developing Internet standards in which case the
  procedures for copyrights defined in the Internet Standards process
  must be followed, or as required to translate it into languages
  other than English.

  The limited permissions granted above are perpetual and will not be
  revoked by the Internet Society or its successors or assigns.

  This document and the information contained herein is provided on
  an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
  ENGINEERING TASK FORCE DISCLAIMS 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.

Revision history

  [[[RFC editor: Please remove this section on publication]]]

  00a  29-Sep-1998  Initial draft.

  00b  15-Oct-1998  Minor corrections and clarifications.

  00c  30-Oct-1998  Further clarifications relating to MRC image
                    coding and resolution.

  00d  11-Nov-1998  Add references for ITU recommendations.

  01a  13-Apr-1999  Provide procedure and decision tables for DIS to
                    feature set mapping.  Update references.

  01b  13-May-1999  Incorporate worked example for black-and-white
                    fax.  Apply several corrections to the decision
                    tables and conversion algorithm.  Various small
                    revisions to the T.30 DIS bit descriptions.





McIntyre/Klyne             Work-in-progress                  [Page 37]


Internet draft    Internet fax T.30 Feature Mapping  10 September 1999


  01c  09-Jun-1999  Incorporate review comments (editorial and
                    reference changes).  Added colour fax example.
                    Updated table in section 5.3 to restrict
                    generation of colour-related parameters to
                    appropriate colour modes.  Fixed table errors in
                    sections 5.1.2 (no color=limited with JPEG) and
                    5.1.3 (MRC-mode<=### rather than =###).  Fixed
                    error in combining rules in section 5.

  01d  18-Jun-1999  Incorporate another round of review comments:
                    editorial, corrections to section 5 mapping
                    tables, update examples, update references.

  01e  22-Jun-1999  Add some commentary to the first worked example
                    that underlines the distinction between T.30
                    mapping and Internet fax.  Moved copyright
                    statement in anticipation of RFC layout.  Extend
                    description of DIS/DTC bit 71 (section 3.12).
                    Changed effect of bit 71 on mapped color depth
                    (tables in 4.3 and 5.3 and example in 6.2).  Noted
                    that the setting of bits 44,45 do not actually
                    affect receiver capabilities (table in 5.2, and
                    update both examples).  Place the Internet fax
                    capability example into subsection 6.1.1.

  01f  23-Jun-1999  Incorporate review comments:  mostly editorial and
                    corrections to feature expression examples.
                    Remove bit 36 from tests for color-levels,
                    illuminant and gamut.

  02a  27-Jul-1999  Section 3.9:  indicate requirement (from T.4) to
                    treat inch/metric based resolution units as
                    equivalent.  Use resolution values from T.4
                    section 2;  allowing for 1% tolerance these yield
                    204x98dpi (metric based) and 200dpi (inch-based)
                    as the basic resolutions.  Section 5.1.2:  capture
                    mapped colour option in table entries with JBIG.
                    Section 5.2:  restrict 100dpi to colour and
                    continuous-tone modes.  Section 5.1.2:  specify
                    subsampling only when (colour=full) and (image-
                    coding=JPEG).  Update example 6.2 accordingly.
                    Add details of mailing list for discussion.

  02b  10-Sep-1999  Updated references to image-file-structure to
                    match revised fax feature schema.  Correct small
                    errors in the introduction section.







McIntyre/Klyne             Work-in-progress                  [Page 38]