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Re: "Binary XML" proposals
- From: Claude Seyrat <email@example.com>
- To: firstname.lastname@example.org
- Date: Tue, 10 Apr 2001 18:55:21 +0200
It seems to me that a debate "binary format vs textual format"
is irrelevant. It is clear that none of them is the perfect format.
Both binary and textual have their pros and cons.
XML defines a very powerfull and generic framework for managing and
processing structured information: very simple APIs (SAX, DOM, etc..),
generic query language (XQuery), locators (XPath), transformations
(XSL-T). New concepts are emerging like infosets which, among other
thing, clarifies the notion of validation and typing, etc..
In certain environment, like broadcast or handheld, CPU, memory and
network ressources are very expensive. For instance, in the multimedia
indexing domain, there are applications which need very large
structured AV metadata stream (might become as large as a video
stream) with very strong constraints in terms of compression,
filtering and streaming. A textual format would in these cases be
a terrible burden. However, it would be very damageable to forbid
interoperability with XML environments.
Therefore, binary formats will continue to exist. The new challenge
is not to replace one format or the other, but to make them as
compatible as possible. It should be very easy to switch from one
format to an other. The effort spend to design an XML language should
be reused for the binary format. Finally, a "text-designed
application" should be easily adapted to deal with a binary format.
When designing MPEG-7, the following policies have been adopted:
- to stay as close as possible to the XML spirit by the adoption
of a textual version designed with XML Schema,
- to define a binary format that uses XML Schema definition to
generate an efficient encoding scheme,
- to allow one to decide whether he wants to use binary or textual
Since the beginning, MPEG-7 has been XML driven. The MPEG-7 community
is very reluctant to follow another development path. However in
MPEG-7 everybody recognizes the need for a binary format.
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