Someone who is actively creating and publishing original content to an audience on one or more media platforms.
Wikipedia explains in detail about Content creation. Click to read more.
Content creation is the contribution of information to any media and most especially to digital media for an end-user/audience in specific contexts. Content is "something that is to be expressed through some medium, as speech, writing or any of various arts" for self-expression, distribution, marketing and/or publication. Typical forms of content creation include maintaining and updating web sites, blogging, photography, videography, online commentary, the maintenance of social media accounts, and editing and distribution of digital media. A Pew survey described content creation as the creation of "the material people contribute to the online world."
For the special case of videos, you may use "Video Content Creator", although I've only seen "content creator" used, generally.
After googling, I've found a lot of job profiles with the title "Video Content Creator", so there's that.