I have no idea why you can store and retrieve images but not video files; there is no difference. However, for ASP.NET applications, I would recommend to keep both images and video files as file in the server-side file system, under some set of unique names, and store just those names in your database.
For playing you can use, first of all, HTML5
<video>
element:
https://en.wikipedia.org/wiki/HTML5_video[
^].
—SA