The MLA has not yet prescribed a citation format for YouTube videos. The example below is based on the format recommended by Purdue University's Online Writing Lab (OWL) website.
"Title of Video." Title of Container, uploaded by Author, Date of Upload, <URL>.
IT: (University of Lethbridge Library)
WC: "The Book2Net Spirit book Scanner, in your Library." Youtube, uploaded by Univeristy of Lethbridge Library, 30 Jan. 2015,
www.youtube.com/watch?v=_G4uRvMb5jU.
NOTE: For works with no page numbers, such as YouTube videos, it is preferable to include the author's name in the text and omit a parenthetical reference altogether.