With loads of pre-set formats available for almost any standard: Android, Apple, Playstation, Vimeo, YouTube, Windows, and Matroska, among others, this app is capable of reworking videos at up to 4K resolution and almost any aspect ratio you need. The only drawback is that outside of presets, you have to adjust everything manually in order to set up dimensions, codecs, apply cuts, modify subtitling, bitrate, etc.
Once you've made these changes you'll get a full preview of your video, and can watch as the final version of your file is fully rendered and saved at within the route you preselected. Handbrake is no doubt one of the best free tools in this field. Its main appeal is that it offers you a minimalist interface with a whole arsenal of possibilities without overcomplicating things like other editing suites do.