We double checked on Hostgator.com’s specification page and found out the video streaming feature is only available in shared and dedicated server. Its not available in Hostgator reseller or VPS.
All their web hosting plans that support streaming video are come with GD2 graphic library and ImageMagick. With these features in place, the plans are supporting streaming audio and video. It also includes free module, apps and tools for supporting this features. Here are the main specification (from Hostgator.com website) that allows video playback in their hosting plans.
With our own Hostgator Baby plan, we are testing this and confirmed video streaming is a supported feature. What we did is uploaded a small video files to our hosting space and later add the video into this Hostgator review blog via flash plugin support. With these, we can add any video in here, view it and playback directly online. You can view the video below and check the playback speed.