Convert Other Format to MP4 1. The file is then e-mailed or available for download form Zamzar servers. Convert video to optimized preset for almost all of the devices. If you have a series of files that require conversion you should strongly consider downloading the full desktop version of a converter. Edit videos with the advanced video editing functions like trimming, cropping, adding watermark, subtitles etc. You can click the Output icon at the bottom of the main interface to find the final MP4 files. Rather than using the old format or being limited in your editing options, converting 3GP to MP4 to give you greater levels of compatibility with use of the files on your computer, editing for mobile devices as well. This will help to save you time in the uploading and downloading process.