My question is about copyright of videos. I want to use this video inside my demo web base video player,but i do not know any thing law of copyright or license of video. how can i check for this video license ? Thanks.
Anything published anywhere is automatically copyrighted, with all rights reserved to the author or publisher. The source of this video is known, so your obvious choice here is to contact the publisher and ask permission.
This is a promotional video, so it's very possible that they will permit your use, with proper attribution or for a small fee. But you have to ask, and they have to agree, for your use to be legitimate.
Often short clips for demonstration purposes qualify as fair use, however you can't generally use more than a few seconds. Even video clips that have been released on the Internet are not necessarily safe to use as the content may still require you to have a license. Your best bet is to contact a lawyer since fair use varies greatly from jurisdiction to jurisdiction or look for content that is released under an open license such as creative commons.