Hello. I plan to do a presentation in one of my engineering classes on a/v formats. This is a broad enough topic, so I think I may want to just focus on audio. But, depending upon how much info I can gather in the next coming days will dictate whether or not I will delve into video formats. So, can anyone point me in the right direction to find technical information about a/v formats like sacd, surround sounds (dts, dolby), dvd, hdtv, etc.? I am aware of howstuffworks.com, and have also begun researching at dolby and sony. Thanks in advance for your help.