Hello,
The MediaElement (ME) uses the Internet Explorer (IE) file cache system. Using this system guarantees that the cache will we cleaned out periodically do that unnecessary files don't clutter up the system. If you want access to the file data it is recommended
that you use something like HTTP client to download the file and then point the file at the ME. Keep in mind that in this scenario the ME does not support progressive download. Because of this you must download the entire file to disk before passing the file
handle to the ME. If you would like ME to handle progressive download and archive the file at the same time you will need to write your own custom network file source. Keep in mind that writing a file source must be done in C++ MoCOM and cannot be done in
any managed language.
I hope this helps,
James
Windows SDK Technologies - Microsoft Developer Services - http://blogs.msdn.com/mediasdkstuff/