Software for HD video stiching and packing?

Hello world

I recently bought the Panasonic Lumix DMC-520 ultra-compact camera, which has a HD video capability at resolution 1250x850. However, Videoimpression2 and Mediaimpression, not to mention Avidemux, Avimuxgui for non *.mov files and Virtualdubmod, bundled with the package and that I've found as a free video software, can't combine nor save video files of resolution over 800x600. Can you tell me a software that can combine and pack mov-files into x.264 AVF format, when they are of resolution 1250x850?

Teemu, Rovaniemi, Finland

moved this to another forum, hoping you get more help here than in off-topic.

adina