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From: mhsc@oce.nl (Maarten Schoonwater)
Newsgroups: comp.protocols.iso.x400
Subject: Re: DATA Compression and X400 standards
Message-ID: <2494@oce-rd1.oce.nl>
Date: 13 Nov 90 20:24:03 GMT
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Reply-To: Maarten Schoonwater <mhsc@oce.nl>
Organization: Oce-Nederland bv, Venlo, the Netherlands
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The discussion on data compression makes it very clear that there is a need
for standard data representations and formats for interchange. Now the
global community is coming more and more together we must learn to speak
common languages.

In ODA (Office Document Architecture) the problems that are signalled here
are solved to a great extend. ODA defines different Document Application
Profiles for different levels of interchange. The simplest form only
contains text, level 2 and 3 also graphics. The bitmap graphics in the ODA
documents can be compressed according to the T.4 and T.6 compression
standards (i.e. fax group 3 and 4). When you send an ODA body part over
X.400 you declare the content type (the profile level). The receiving X.400
system thus can check whether it can decode this level of ODA and thus
refuse the message if desired.

ODA only solves the problem for documents, there should be additional
standards for other applications. For pure bitmaps there are already the
CCITT facsimile standards that can be used and declared in the various body
parts. Compression is therefore already solved.

Maarten Schoonwater
Oce-Nederland BV