check this
Hi, I did my homework when buying my TV last December...
HDMI is the best current connection for video and audio between a DVD, a Satellite receiver, amplifier, and a TV or monitor.
Imagine the best image you can have on a TV, High Definition.
http://en.wikipedia.org/wiki/HDMI
Generally speaking the image resolution is higher, so the picture you get is much better than with the other connections.
DVI is similar but only has the video signal, no audio on it, mostly used with some computers and monitors, also used on some TVs out there.
http://en.wikipedia.org/wiki/Dvi
Depending on the source of your video signal with either HDMI and DVI if it's not a s good as the display you can see a bad image because the higher the resolution more details to show...
So the best way to go is have a good match from your video source and the display you'll use.
The S-video handle less resolution, like a good VHS movie.
http://en.wikipedia.org/wiki/S-video
RCA are those yellow, red and white cables taht are typically used for connectin a VCR, DVDs, stereo music player, etc...
Less resolution and image quality, for your audio only 2 channels (left and right)
http://en.wikipedia.org/wiki/Rca_cables
The optical audio connection allows you to have sound signal of multiple channels connected with just one cable, so you avoid using many RCA cables like in the past, so for a home theater you'll need a source device with that output and a receiver or TV that handles that input, and of course the nice set of speakers and subwoofer...some Macs had that output! I'm not sure if some of the new ones do have it...
Other important thing to consider is the aspect ratio of your signal and the screen resolution.
http://en.wikipedia.org/wiki/Hdtv
In my opersonal opinion HDMi is better and more expensive, but the prices are going down quickly, DVI is not the latest, also there are some adaptors DVI to HDMI...but who want that....only those who already have a DVI display and/or source...and the rest is old stuff, so if you are investing in new gear do it thinking in when you are planning to replace it later...
The wikipedia can help you go to any other topic you want to dig in...
Baseball Play Offs are coming....so nothing like having a nice TV set with the proper features to enjoy!!!
PD wireless HDMI is currently under investigantion and development, so sometime in the future we'll live without cable...
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1949 Ford