Here is a method that can be used to post content in Blackboard, such as a video file, outside of the context of a specific Blackboard course site.
Link to full view: http://screencast.com/t/wtyivHjj
For this method we recommend using "web-optimized" .MP4 files so that they will playback smoothly.
To convert your video files to web-optimized .mp4 format, try the Handbrake video converter. Here is a picture of the correct settings to use for Handbrake: http://screencast.com/t/M9ukbpwo