It\'s still hd if you have yellow, red, and white cables..if it\'s an hdtv of course..
That\'s where you are wrong. yellow is for "composite" video. the remaining red, and white cables are for audio left channel and audio right channel.
yellow coded cable is for only sending 480i SD picture where all the 3 color (red, blue, and grayscale) are sent in one single cable in analog. Causing color smearing because 3 colors are cramp into one signal path. It cannot output anything higher than 480i, like 720p, 1080i, or 1080p. Thus making it only SD quality.
Not even S-Video can send anything higher than 480i. Again, that\'s the highest quality it can send for S-Video.
Only Component Video can send anything higher than 480i, such as 720p, 1080i, and even 1080p.
Component Video cables are color coded like this: Red, Blue, and Green. Which the Red cable send the red color channel and can be in 480i, 720p, 1080i, or even 1080p for each color channel. Like Blue coded cable send blue color channel. Green actually send luminance or gray scale channel. Again, each color channel can be in standard defintion 480i or high definition 720p, 1080i, and 1080p.
Another popular video connection for analog that support SD and HD signal is VGA which is mostly use for hooking up a computer monitor.
VGA is a single cable that have like 15 pins in them. But doesn\'t mean it has to uses all 15 pins. Because it can support up to 15 pins, each pin can send the 3 primary color channel separately like red, green, and blue signal (RGB), hence no color smearing. That means there are 12 pins left, which can send other information which I am not really familiar with, but i think it might have to do with resolution and refresh rate and other data information.