tutorial video not working

[gokumike]

i downloaded one of the videos from http://www.hl2modcentral.com/tutorial.php?id=36&cat=0

and when i tryed to open it, it said it was a file that quicktime doesn't understand, anyone know what is up, someone mentioned codec, and ive tried getting some but it doesn't work?

 

[jmjneary]

underneath the link it says you might need a codec download that and it should play correctly