Seralised formats....universaly good for mobile engines?

[Darkflame]

Next week I'm going to a AR standards meeting;
http://www.perey.com/ARStandardsMeetingFeb2011.html

We are discusing with a few companies possible standards for Augmented Reality applications; both world/data link methods as well as formats used once that link is made.
Naturaly 3D formats for AR use is one of the most important things being discused, so I'm just seeking out feedback on (from a engine standpoint) what makes a good format.
With jpct I know seralisation speeds up loading....is this a "generic" good thing for formats on low end devices, or just specificly good for this engine?
Also, many are talking about markup based languages like expansions to VRML, ARML, KARML etc, as well as KML type stuff. Are these formats relatively "heavy" or not much of a problem given todays hardware?

This isn't specific requests about what jpct should support in the future, more just hypothicaly the sort of recomendations that would be usefull to make.

[EgonOlsen]

jPCT's .ser-format is basically a data dump, which is why it loads so fast (and is a little bit on the large side). In general, i would prefer a binary format for mobile devices, because it doesn't require any string operations and parsing like XML and similar formats do. On Android and using the Dalvik VM, the bad garbage collection of Dalvik is another point to consider. A binary format creates less garbage (if implemented properly) then loads of String instances being created and destroyed while parsing and converting some ASCII/XML based format.

[Darkflame]

Thanks for your feedback, I passed it on during the presentations.
The president of mobile for NVidia, acting on behalf of the Kronos group, said basicly the same thing as well, - essentialy xml based formats (including their own Collada format) are good for storage/creation but not for delivery.

However, it seems that X3D format might well fit the bill despite that. It seems a rather flexible 3d format with a lot of support, but also a binary variation as well (which isn't used much yet, but for the mobile market that might just be perfect).

http://en.wikipedia.org/wiki/X3D
 
Discusions are still going, but it seems this might be the top contender at the moment.
If you get a chance to check it out, be sure to let me know as there is still very little feedback from actual 3d mobile coders on this issue.