After you install the application, a pop up should appear asking you to enter a username/customer ID and a license number. This is the only way to register the application. The problem consists in acquiring these details, because the official website doesn't list the product anymore which means it's impossible to acquire an activation code.
You can browse alternative applications using the following link: http://software.informer.com/search/mp4+converter
The search has been narrowed down to display only the converters that are capable of handling MP4 files and provide output for a wide number of audio and video formats.
