Media Express XML description

We have volunteers operate our capture software and have accidentally overwritten avi files from earlier in the
day.

Is there a published or unpublished spec on the XML file used to initialize the software?

Are you referring to overwriting the XML project file or overwriting clips?
If it is the latter, the data is gone without data recovery software. I would recommend investigating free data recovery software.

I want to initialize the XML file changing the filename of the avi using the date and hour in a script
so volunteers don't overwrite already captured video in the future.