I am trying to work out an approach to developing a desktop application that would play movies, games and various flash material such as flash games and flash flip books. The movies will be in both video format and swf format, and will need to be compressed and encrypted for transmission to users and decompressed/decrypted by our player so as not be viewable by other players.

The installer would be platform / OS dependant. The player / user interface would need to be written in a 'portable' language so it can be cross-complied to different platforms ( Windows, Linux/Android, Mac, Iphone/Ipad, ... ) If this is not possible than atleast it should work on the PC and MAC.

The idea here is to ideally maintain one code base so the client will experience the same interface on each platform we support.

My questions are-

What would be the best approach to develop these applications?

Is it possible to acquire public / open source code where much of the work has already been done and then

add my code to it?

If open source code is available where could I get it from