Format: 

Author, A. A. [Screen name]. (Year, Month, Day). Title of video [Video file]. Retrieved from URL

Examples: 

Emergency Awesome. (2015, July 21). Gotham season 2 preview: Batman villains rise [Video file]. Retrieved from https://www.youtube.com/watch?v=m4nCn1tiItw

In-text: (Emergency Awesome, 2015)

Davidson, F. (Producer), & Davidson, J. (Director). (2012). Building mathematical competencies in early childhood [Video file]. Retrieved from http://digital.films.com/PortalPlaylists.aspx?aid=16881&xtid=52082

In-text: (Davidson & Davidson, 2012)

Young, R. (Writer & Director). (2015, May 12). The trouble with chicken [Television series episode]. In R. Young (Producer), Frontline. Retrieved from: http://video.pbs.org/video/2365487526

In-text: (Young & Young, 2015)

Notes: 

Include the author's screen name (if available) in brackets after the author's name. If only the screen name is known, provide it without brackets. Add a description of the video form (e.g. Video file, Television series episode) in square brackets immediately after the title of the video followed by a period.

Source:
APA - 7.07, no. 49, 51
APA (ER) - no. 56