Mr-Nuts

I am looking for a video editing software that will work with my MP4 file formats from the camcorder. It is 720i HD and records in MP4 file format. I want to be able to output HD 16:9 (wide screen) files for upload to YouTube or other sharing sites and also watch on TV or share on disc. Question #1: Will this software allow me to work with the MP4 files and have the output desired ? Question #2: Will this software allow me to open existing files on my hard drive or require me to "Capture" them, creating a copy of the file for use by VideoPad ? Bill