If you do not already have a copy of the video to upload, you can download the video from Mediasite using the Video Podcast delivery option. If your video is more than 15 minutes long, you may need to verify your YouTube account first. Upload your video to YouTube and edit the automatic captions

Creating and adding closed captions should occur after your final edit. For example, if a video already has captions, and you edit the video to remove the first 30 seconds of content, the existing captions will remain unchanged, meaning the captions will run 30 seconds behind the edited video. Mediasite will not automatically edit or remove portions of existing captions. Important Note: You should make any desired edits to your Mediasite video before you create and add captions. A popular technique described below is to upload a copy of the video to YouTube and then use YouTube's caption editor to fine-tune the automatically generated captions. There are a variety of products which allow you to transcribe and add timings to create captions for videos.

HOW TO: Create your own captions using YouTube's caption editor

Download closed captions from youtube