Why a video dissapear from my Lumia and where I can find it?

[WPCentral Question]

I cannot find a very dear to me video on my phone. I haven't checked before the settings for onedrive to back-up videos too (I did not know it :-((( ) and I cannot find on my phone the video. Other smaller videos from same period of time still are but this longer one it's not. Can you pls pls help me??