Welcome to new mail list for discussing an XML version of

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• Previous message: Ian Medland: "Dynamic Line Art in COR1"

Welcome to MHEG-8 list. For starters I've included all the persons who
attended the MHEG Tokyo meetings, plus several others that have contacted
me since to ask to be subscribed. In addition I've CCed others and the
MHEG mail list who I think may have an interest in this work.

It is intended that only issues related to the XML TR will be discussed on
this list.

If you want to join the list, or know of persons who want to please let me
know.

If you wish to un-subscribe please let me know.

I've attached here the two documents on this topic from the Tokyo
meetings, in spite of fact that they are mounted on the web site, as I know
some of you who did not attend Tokyo, and want direct access to them.

The proposal to develop a TR mh_n1172 needs further work before or at least
by the end of the Seoul meeting, March 15 - 19. We need to define the
scope. Should we include in the scope the proposed tools that we may want
to include with the TR? What should these tools comprise?

Ideas, ideas let me hear from you.

Also should we make specific reference to a DTD in the scope and what about
the other XML resources that will be used or developed? What are these,
where do we retrieve them. And what about references? Any really good books
and or URLs for XML? We need some XML experts to work with us? Do you know
some that may wish to help?

Document mh_n1175 contains the summary of our discussions at Tokyo. This
document needs some serious progression, and I would like to see it evolve
into the WD0. Our colleagues in Korea said they would provide an editor
(Feb 15) and a first draft of the WD0 by Korea meetings, I'd like us to
help them along with this as much as possible via this mail list. Your
contributions are sorely needed and welcomed.

Also, if you will recall we agreed that the Korean NB will propose a 3rd
workshop for the first day of the Seoul meetings. I believe we should have
at least one session on the proposed XML notation for MHEG-5. By that time
we should have identified the problem areas and some of the issues involved
in developing XML-centric MHEG-5 engines. MHEG-5 XML applications may also
be a topic for consideration at the workshop. What about discussing the
possible tools that need to be developed, or are already available?

We'd like more commitments of NB support so if you can contact any
colleagues in rest of Europe, Asia etc please do so and ask them for this
support. What about the Austrian, and the Spanish, Portuguese, can any of
you contact them? If anyone can contribute time and editorial support let
me know. I will certainly solicit other support at the SC 29 Plenary in
Seoul. I've sent this to the Swedish NB Delegate and would like her to pass
this on to her experts in Sweden, and ask for support from the Swedish NB.

I have strong feelings that we can and should progress this work via email
and the web site as much as possible. We can use the face-to-face meetings
to get final approvals, resolve ballot comments, and prepare administrative
details. If we agree as a WG, we may be able to progress this TR rapidly.
Should we do this, may be an important question to answer?

My apologies if you receive multiple copies of this mailing. As soon as I
get the membership of the list sorted this will not happen ( we hope).

Thanks for helping me to get this mail list organised. Thanks to the Tokyo
attendees for getting this started.

Best regards

Tom
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INTERNATIONAL ORGANIZATION FOR STANDARDIZATION

ISO/IEC JTC1/SC29/WG12 Multimedia and Hypermedia information coding Expert Group (MHEG) MHEG 98/N1175

TR 13522-8 XML Notation for MHEG-5

WG 12 is studying a proposal to create a new work item in the form of a Technical Report that would provide XML notation for MHEG –5 and other tools for the use of XML application developers.

Introduction

MHEG-5 ISO/IEC 13522-5 is a base standard for interactive multimedia presentation that is being widely implementers by digital television broadcasters. It has been often stated that the propagation of the Standard would be enhanced if it were more readily accessible to the content authors or application developers. At present the normative components of the standard are unambiguously expressed in ASN.1 and EBNF textual Notation. The textual notation was provided as an alternate encoding because it is human readable, but it is still thought to be an esoteric format, unfamiliar to many potential multimedia application developers. Both of these formats are well known to most computer scientists. It is thought that the standard would attract a wider user community if a more familiar "tag type" markup language was used to express the elements of the Standard. XML, which is a subset of SGML, has been suggested as the appropriate markup language to use because a very large number of web authors already use HTML, which is closely to related to and has similar features to XML.

Rationale

Since it is expected that many applications or application components can be retrieved from the Internet or written by persons who know or use HTML document formats that an XML centric MHEG-5 engine would appeal to a very wide audience of potential users. It may also be the case that much content material will be stored on Intranet servers. This material might be easily and quickly inserted into broadcast applications. In addition it is expected that the web and MHEG technologies will eventually merge. Hence an XML version of MHEG-5 may be consistent with this action when it begins to take place.

One scenario could be that broadcast reporters write, author and load multimedia material onto a web server, from which TV editors can retrieve the data and compose content relevant to the programme schedule of their companies.

The Model

On the surface it would appear that an XML version of MHEG-5 is not a difficult task to accomplish. But it is not only the translation of the ASN.1 or the textual that must be considered here but the manner in which the MHEG-5 engine is implemented and interprets the behaviour of XML expressed applications.

At this stage in the study of this TR the authors have identified several aspects of XML that must be supported by the MHEG-5 interpreter. For instance, browsers are good at presentation but do not yet support synchronisation features, which is an important feature of MHEG – 5 systems. In the case of time-dependent synchronisation it is felt that SMIL plus XML might provide an appropriate solution. For other, (non time-dependent) synchronisation it is may be the case that the Engine/Browser can be modified to support such features directly from the XML of MHEG-5 application

Architecture of a MHEG-5 XML System

An overview of the XML MHEG-5 system features is shown in the diagram below. The combined and appropriately coupled nodes: XSL, DTD, XML Parser and Browser would handle and present MHEG-5 conforming retrieved data and applications

Fig: 1 Overview of XML MHEG-5 System Architecture

Fig.2: Detailed Architecture of XML MHEG-5 Interpreter

In the diagram above the component of an MHEG-5 interpreter is modified to reflect the requirements of XML applications. XML code is input to the object manager where it is parsed, an object table created and XML type data structures are identified. Within the interpreter there resides an XML browser which might encapsulate an MHEG-5 XML processor and SMIL engine as a Plugin. It is within this component that MHEG-5 action, event, and link processing takes place. At this time it is not clear how the functionality required in these modules can be designed, coupled and implemented.

Developing an MHEG-5 Markup Language using XML

In the diagram below a first "stab" is made at expressing how an MHEG-5 ML might be designed using XML resources.. One approach that might be pursued is to insure that all link actions within the XML MHEG-5 Engine can be interpreted by defining other synchronisation mechanisms..

Fig.3: Components of an MHEG-5 Markup Language

Conclusions

The above contribution represents an attempt by several members of WG 12 to begin development of a first cut of a WD for the proposed TR 13522-8.- "putting flesh on the bones" Despite the fact that there is no designated editor for this part of the Standard at this time, it is felt that discussion of this TR can begin on the mail – list and the Web facilities, in order to progress this work before the Seoul meetings in March. It is intended that this document will be circulated to WG 12 members to ask for their comments and help in furthering the progress of this proposed Technical Report. Please be advised that the creation of this work item is still in the discussion and study phase and we do not yet have official approval for the creation of such a work item. But because of the need to progress this Work Item at an appropriate pace we would like to have contributions on this topic before the next MHEG meeting in Seoul, Korea March 15, 1999. It is intended that this topic will be discussed in some detail during the MHEG workshop in Seoul – to be held on the first day of the Seoul meetings.

A separate mail list will be set up for TR MHEG-8 activity. Members wishing to participate in the discussions on that mail list should contact the WG 12 Convenor, Dr. Thomas Casey at tcasey@tcasey.demon.co.uk and let him know of their desire to join the list.

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INTERNATIONAL ORGANIZATION FOR STANDARDIZATION

ISO/IEC JTC1/SC29/WG12 Multimedia and Hypermedia information coding Expert Group (MHEG) MHEG 98/N1172

Outline
The proposal is for WG 12 to establish a sub-group to produce a Technical Report, TR 13522-8, on the representation of MHEG-5 notation in the XML markup language, in addition to the Text and ASN.1 formats that already form part of the standard.

An XML document consists of two parts: a Document Type Definition (DTD), in which the format of the document is expressed; and a second component, a Style Sheet (SS) set out in the (e)Xtended Style Language (XSL). An XML capable browser, such as Microsoft Internet Explorer 5.0, will incorporate a DTD parser and an XSL processor, and thus will be able to combine and render the two components into a final displayed document. The situation is   summarised in the following diagram:

The working group believes that the expression of objects of the standard MHEG-5 classes should be a fairly straightforward matter and that it will be possible to produce specifications of such objects in XML that are isomorphic to specifications in Text Notation and in ASN.1.

The work would produce the following outcomes:

1. an XML definition of the MHEG-5 external representation
2. software tools for conversion between XML, Text Notation and ASN.1
3. extensions to MHEG-5editing tools to output XML format object definitions

Justification
WG12 believe that this work will have the effect of raising awareness of the MHEG-5 standard among the Internet community, as XML is being widely adopted as a means of encoding electronic documents and users are familiar with tagged formats. It will constitute a valuable first step towards the wider aim of integrating MHEG-5with existing Web technologies. Successful conclusion of the works may have an impact on the question of MHEG-5Engine construction, as any XML-capable browser would have the capacity to render MHEG-5 objects.

As we are proposing an alternative notation, no modifications to the MHEG-5 standard will be necessary.

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• Previous message: Ian Medland: "Dynamic Line Art in COR1"