Based on bug #666306, comment #68 The specs say that the play button animation should show for videos having the width greater than 128px or height greater than 100px (128px - 28px for the control bar) (bug #666306 comment #65). Currently, the animation shows only for larger videos (from 276x155). It would look better if the animation also worked for smaller videos, at least for those having height >128px (not necessary for h>100px as it was initially intended), since the video looks large enough to show it.