Editly
Slick, declarative command line video editing & API
...Editly has a simple CLI for quickly assembling a video from a set of clips or images, or you can use its more flexible JavaScript API. Inspired by ffmpeg-concat, Editly is much faster and doesn't require much storage because it uses streaming editing. Editly aims to be very extensible and feature-rich with a pluggable interface for adding new dynamic content.