User blog comment:NOBODY/Walkthrough run/@comment-1455034-20120925140303/@comment-3060206-20121004050919

To directly upload a video, you'll have to convert it to one of the supported video file formats (seen on Special:Upload, I think .ogv's the video file extension that is supported). Then, you can use Special:Upload to upload the video.

You can also embed videos on the Wiki using the "Video" button on the right rail of the editor (amongst the Picture, Table, etc. buttons). Just click "Video" and follow all prompts. It is then inserted under the prefix File:, which is probably where the idea of "uploading" the videos comes from. This also shows up in the upload logs, so I usually just use it for videos meant for mainspace pages and use the youtube tag to embed personal ones.