You  can upload videos, as well as photos and PDFs, to your own Memories memorial from a phone, tablet or desktop. 

If you’re invited to a memorial as a Contributor,  you can do the same thing.

You can upload photos of the most common photo file formats, either in JPG, PNG, BMP or GIF while videos in .MP4 and .MOV formats. Your video must be less than 5GB in size. 

Link to related articles: 

• Do I have to create an account to post content?
• Add a Memory to a Timeline