Visit videojs.com for an overview.

The purpose of the change is to be able to play video in given time range within the clip. For example if the original clip is 45 seconds long, but you want to play clip between 5th second and 25th second.

With additional [rangeplay plugin] you can expand http://liftoffllc.github.io/pages/html5-video-2/

View Example of original videojs with rangeplay plugin