You can download the original uploaded file from your account by selecting the "Download" option from a video's context menu.
To access the context menu of a video, click on the title of the video in your dashboard.
If the video has been on the platform for over 28 days, the original file will need to be retrieved from archives before it can be downloaded. Attempting to download the video will initiate the retrieval process, and you will be emailed when it becomes available to download. It can take 12 hours or more to retrieve the file from the archives. Once it is recovered, the original video version will be available for 5 days.
The retrieve is only for the "original files." The HD and SD versions will be available to download right away.