jxr@THUMPER.BELLCORE.COM (Jonathan Rosenberg) (08/18/90)
Original-posting-by: jxr@THUMPER.BELLCORE.COM (Jonathan Rosenberg) Original-subject: Re: Multi-media mail standards Reposted-by: emv@math.lsa.umich.edu (Edward Vielmetti) [Reposted to comp.text from the newsgroup(s) comp.mail.multi-media.] From: Einar Stefferud <Stef@nrtc.northrop.com> Date: Thu, 16 Aug 90 11:45:57 -0700 Message-Id: <21001.650832357@nma.com> Sender: stef@nma.com > What are the standards bodies (ccitt/iso/iec) doing in the MMM arena? There are a number of standards activities involving multi-media documents (that's the nice thing about standards: there's so many to choose from :-) We could probably (certainly) argue about whether a mmm standard is the same as a mm doc standard. It's undoubtedly not the case that a mm doc standard can just be taken as it is & used as a mmm standard. But, a mm doc standard (in particular, one with a defined interchange format) has got to be a good place to start. Anyway, here's the (dejure or de jure) standards activities relating to mm doc's that I know of: 1) Office Document Architecture (ODA). You are probably somewhat familiar with this standard, which is ISO 8613. ODA defines a document architecture for multi-media documents that allows the specification of logical structure (the logical organization of the document) and/or its layout structure (how thw document is to be imaged). The ODA architecture makes it easy to plug in new media types. It currently supports multi-font structured text, geometric graphics & raster graphics. There is lots of work going to introduce new media (e.g., audio, video, spreadsheets). ODA is a large, complex standard. 2) Compound Document Architecture (CDA) Digital Document Interchange Format (DDIF). CDA is DEC's mm doc standard. It appears to me that it actually encompasses a rather large suite of sub-standards, tools & applications. DDIF is, I believe, one of the possible representatiuons for a CDA document. DDIF is based on a early version of ODA, which was then extended/modified to take care of some perceived problems. Unfortunately, I don't know enough about CDA/DDIF, but my impression is that they have done a nice job & have that it is fact, a great improvement over ODA, while retaining many of its good points. 3) HyTime. HyTime is an ANSI "Draft Standard" (I think I have the terminology correct), which is actually a subset of a larger standard known as the Standard Music Description Language (SMDL). SMDL is an SGML application designed for musical presentations. HyTime is the subset of SMDL that deals with Hypermedia & time-dependent notions. Unfortunately, I don't know enough about HyTime to comment much more on it. Except that it is my impression that HyTime basically presents a shell in which any particular must fill in lots of details to obtain a useful document model. HyTime is onloy a high-level document architecture & leaves the choice of media representations up to applications. 4) Multimedia Hypermedia Expert Group (MHEG). This group is ISO/IEC JTC1/SC2/WG12 & is a sister group to MPEG (Moving Picture Expert Group) & JBIG (Joint Bilevel Image Group), which you might be aware of. MHEG is a fairly new effort & I believe that the group's future is rather uncertain: for various political reasons, they may disappear or be absorbed into the ODA work. Leaving politics aside, the purpose of MHEG is to define an architecture that allows the composition of media objects into "documents" allowing the representation of hypermedia-like concepts & simple time-dependent actions. Like HyTime, MHEG does not define the representations of its content but will refer to other existing standards (particularly those in its sister working groups). MHEG is fairly new & whether it has staying power remains to be seen. 5) Miscellaneous. There are a number of miscellaneous efforts that I know of & can mention briefly. Document Syntax & Semantics Specification Language ? (DSSSL): I always get confused about what the acronym means.) This is a non-standards-body activity (as far as I know) attempting to define an SGML application that has rich logical & layout semantics. I have only seen preliminary documents on it & my impression is that anything real is several years away. Rich Text Format (RTF): is a Microsoft mm doc format used by the latest versions of Microsoft Word (I believe). I have looked at RTF in some depth & my own belief is that it is simply not well enough though out or defined to be a serious contender. > Is there a reason to engage in some more formal MMM pre-standards > activities, such as preceded X.400, X.500 and NetworkManagement. Because there are not enough reasonable examples around, believe it is too early to actually standardize on a mm doc architecture. However, I do believe that the pre-standards activities you are referring to are worthwhile. I would very much like to participate, although I won't be at Zurich. I'll send a discussion paper with Nathaniel. JR
mss+@andrew.cmu.edu (Mark Sherman) (08/20/90)
re: mm doc standards: the Dexter hypertext/hypermedia draft standard I don't know if we should include company "declared" standards, but if we are, then we might as well include IBM's Mixed Object Document Content Architecture along with DEC's CDA and Microsoft's RTF. Another thing to keep in mind about nearly all of these standards: they are primarily organization standards. They describe how to put together various pieces, but the guts of the document are usually encoded in yet another collection of standards, upon which there is also no agreement or concensus. -Mark