[M4IF Technotes] X3D/XMT compatibility

[Mikael Bourges-Sevenier]

Dear All,
For VRML/X3D scenes, do not start with OrderedGroup but Group. Remember to
encompass the whole scene under a unique Group because VRML/X3D allows
multiple top nodes, BIFS only one. Similarly, as Sebastian wrote: take all
proto declarations and put them on top, take all routes and put them at the
end. (VRML/X3D allow those to be anywhere).
Best,
Mike
-----Original Message-----
From: technotes-admin   lists.m4if.org [mailto:technotes-admin   lists.m4if.org]
On Behalf Of Sebastian Voigt
Sent: Thursday, March 20, 2024 8:18 AM
To: tm991058
Cc: technotes   lists.m4if.org
Subject: Re: [M4IF Technotes] X3D/XMT compatibility
Hello
I try the same. Take the nodes under the <scene> element in X3D and append
them to an children-node of an groupe-node in an XMT-A-Document. X3D allows
more then one top-level-node as childs of the scene-element, XMT-A allows
only one. ROUTEs must be after the top-level-node as childs of
scene-element. PROTODeclares are first childs of scene-element.
My XMTs have the following structure (starting at scene-element):
<scene>-
              |
              | ---<ProtoDeclare> {0..n}
              |
              | ---i.e. <OrderedGroup>-
                                                 |
                                                 | --- [your x3d nodes]
              |
              | --- <ROUTE> {0..n}
The header of the XMT-A includes the IOD. If you like build self-contained
MP4-Files, you must append to the Body-node an ObjectDescriptorUpdate-Node
for referenced mediafiles, i.e. for image textures and replace the
url-strings of such references with the OD_ID.
Best regards
Sebastian
----- Original Message ----- 
From: tm991058 <mailto:tm991058   fh-stpoelten.ac.at>  
To: technotes   lists.m4if.org 
Sent: Wednesday, March 19, 2024 7:36 PM
Subject: [M4IF Technotes] X3D/XMT compatibility
hello all,
I'm an austrian student from the college for telecommunication and media. At
present I'm working at my diploma project, which is about authoring
MPEG4-scenes.
I have already made a test-3d scene and exported it to vrml...than I
converted it to x3d..
The next steps would be to make a xmt file out of the x3d file, than to get
bif out of this and than finaly get a mp4 scene...
My present problem is: How can I get from x3d to xmt??
I haven't found any converters and I haven't found any rules how to change
the x3d code by hand (in a text editor) to get to xmt...
I've heard a lot about the interoperability and compatibility between xmt
and x3d... I've read a lot about the compromise and the compact form of
x3d..  someone claimed that it is easy to get from x3d to xmt because of the
compromise form... i've found many statements that there is a high
compatibility between xmt-a and x3d... but nobody is writing about a
practical method to get from x3d to xmt...
Maybe I wrap something...
I would be really glad to hear from someone of you!
Thanks very much in advance!
karin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/mp4-tech/attachments/20030320/29b83d4b/attachment.html