Submittable

Submittable, a YCombinator company, enables publishers with a simple powerful way of crowd-sourcing and curating videos, articles, images, and audio from your audience or contributors. Features include: ability to create custom calls for work in seconds, in-app video transcoding, public and private voting and review tools, and it fully integrates with most CMS platforms via a robust API and White-labeling. Publishers can accept work from any type of device. Clients include The Chicago Tribune, The LA Times, CBS, BuzzFeed, St Louis Magazine and thousands more.

https://www.submittable.com/