Have add_video use NamedTemporaryFile directly (#20223)
Summary:
address comment in #16196
https://github.com/pytorch/pytorch/pull/16196/files#r278676986
cc orionr
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20223
Reviewed By: natalialunova
Differential Revision: D15261528
Pulled By: orionr
fbshipit-source-id: 1aebcc6cb1c9313d890c5b506973855ebc63fb3b
