IETF Fax working group Lloyd McIntyre
Internet draft Xerox Corporation
Category: Work-in-progress Graham Klyne
Content Technology Ltd
5 January 2000
Expires: April 2000
Internet fax T.30 Feature Mapping
<draft-ietf-fax-feature-T30-mapping-03.txt>
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[[INTENDED STATUS: This memo provides information for the Internet
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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].
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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
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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.
Section 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 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.
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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.
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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.
+----------:----------+
:
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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.
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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.
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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 resolution 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 upon 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.
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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.
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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.
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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.
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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.
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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
--+--+--+--+--+--+--+--+--+--++---------------------------------------
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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].
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<------- 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)
--+--+--+--+--+--+--+--+--++-----------------------------------------
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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)
--+--+--+--+--+--+--+--++-----------------------------------------
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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).
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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.
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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) )
--+--+--+--+--+--+--+--+--+--++---------------------------------------
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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) )
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*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) )
--+--+--+--+--+--+--+--++---------------------------------------
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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) ) )
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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
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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
--+--+--+--+--+--+--+--++-----------------------------------------
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| 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])
--+--+--+--+--+--+--+--++-----------------------------------------
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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
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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 sections 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
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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]) )
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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
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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 sections 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) )
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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) ) )
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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)
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(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.
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8. Acknowledgements
The authors gratefully acknowledge 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.)
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[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] RFC 2703, "Protocol-independent Content Negotiation Framework"
Graham Klyne, Content Technologies
September 1999.
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[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
Content Technologies Ltd.
1220 Parkview,
Arlington Business Park
Theale
Reading, RG7 4SA
United Kingdom.
Telephone: +44 118 930 1300
Facsimile: +44 118 930 1301
E-mail: GK@ACM.ORG
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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.
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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.
03a 01-Oct-1999 Update author's address and some references.
03b 05-Jan-2000 Editorial revisions.
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