Video Backgrounds

[creativ3y3]

Hi I was wondering if you have a suggested optimum size for video backgrounds and sliders for your theme at full width screen? I realise there is a trade off with quality and load and amount of secs / audio on or off etc, but looking for a starting point with the aspect ratio. I’m guessing 1080p is probably too big for example? I’m mainly thinking of use for a background 5 sec max loop kind of thing to add visual motion interest nothing more and want to have the best size before investing in stock footage at the wrong size.

Many thanks

Ticket