click on x bottom right to maximize, or double click on the video.

Click play if it says unsupported video (firefox on android)
Uses html5 video and webvtt.
Video clip is from https://peach.blender.org/.

http://www.w3schools.com/html/html5_video.asp - supported type of media files in browsers
http://www.w3schools.com/tags/tag_video.asp
http://www.sitepoint.com/comprehensive-look-html5-track-element/

2012
http://www.html5rocks.com/en/tutorials/track/basics/

http://www.w3schools.com/tags/att_track_srclang.asp

You can use width and heigh parameters inside video tag.