Re: "Binary XML" proposals

[Claude Seyrat <cseyrat@acland.fr>]

Dear All,

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 
  format.

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.

Best regards,
Claude.


-- 
______________________________________________

Claude Seyrat

Expway c/o Acland
18 avenue Georges V
75008 Paris
tel: 33 1 56 62 11 05
fax: 33 1 56 62 11 11
mail: claude.seyrat@expway.fr