You have noticed that users in your community have the option to publish to your community whenever they create a new video item.
For example, if your community is named "Main", users are able to select the option to publish a video to the Main community:
This article describes whether or not you can prevent users from having this option available to them.
Users cannot be prevented from selecting this option when they choose to create or publish a video.
When users select this option, the video that they create/publish gets stored in their "User container". This means that the video is actually contained within the user's account. By design, all users in Jive have the ability to publish to their user container, and this functionality cannot be removed.