Here you can use either absolute or relative urls only.
Possible values:
An absolute URL - points to another web site (like src="http://www.example.com/small.mp4")
A relative URL - points to a file within a web site (like src="small.mp4")
When you add video into your web site,you can use it as below:
<video width='300' height='200' controls>
<source src="/PtImages/Sravi-klokesh/Priorus-1394794109.mp4" type="video/mp4"/>
<p>Fallback code if video isn't supported</p>/
</video>