Liquivid Video Stabilization is an easy-to-use app that reduces camera shake from handheld footage or clips taken with action cameras or aerial vehicles (e.g. quadrocopters).
Imports all common video formats and codecs in any resolution (including HD, 2K, 4K).
Exports videos as MP4 files with H.264 codec.
Note that stabilization in post-production always implies that a part of your video will be cropped away: The stronger the camera shake, the smaller the remaining region of your clip. The app will automatically suggest an appropriate output resolution.
