If you have access to Virtual Demo Videos you will see some menu icons in the Action menu to manage your videos.  'Manage Audio' allows approved users to record a voiceover to be used in your video.  'Build MP4' is only visible if you have the Manual Virtual Demo role and prompts for a new video to be built.  'Download MP4' allows users to download a MP4 video file, but users can also view the video directly within AutoPlay using the 'Preview Video' button.