What is the proper method of citing from a video
It might sound odd to use video material as a source, but this is a frequent issue in modern History, to name one area of research. 20th-century propaganda is an example of a topic that would include primary sources that are videos, posters, or radio material. 

The Havard citation includes guidelines, see here for a guide from the Open University. From page 33 on video sources:


  The Apprentice (2008) BBC 1, 14 June [Online]. Available at www.bbc.
  co.uk/iplayer (Accessed 16 June 2008).


On page 55 on (unpublished) interviews:


  Interviewee, A. (year of interview) Unpublished interview conducted
  by Interviewer Name, date of interview.


If you have the time, you could transcribe the interview yourself to make it easier to trace back the source. A good term to google is "Harvard Referencing for Visual Material". (Or whatever the appropriate referencing style is for your publication). I would cite it as an interview that you accessed online. The more you know about who conducted it, the better. 

Imperial College London have an even more extensive guide on this, see page 12 here:


  Example:  Kirk, T. Interviewed by: Picard, J. News Night Live. (24th June 2001) 10pm Channel 6.


My approach would be to see which referencing is most common in the area that you work in, to ensure consistency.

Edit: including time-stamps:


  [...] the contribution of water damage can be seen at 2m33s in to the
  video (BBC, 2009).


See page 14 here.