I looked into the available options at some length a while ago when I was doing two video projects for clients.
At first I thought of the 2 most obvious options.
- Windows media – wmv
- QuickTime – Apple mov
Both of these would be acceptable because they at least buffered the file so it would start to play as it downloaded from the web server. Note: I was being asked to host these files. Neither client wanted to pay for a streaming media service. In fact, one of them did have a streaming media service and the front-end on it was, quite frankly, bloody horrible.