Video Asylum

Posted by David Aiken (A) on September 09, 2006 at 14:24:10

In Reply to: why does cable company claim high definition, when the box has only component outs ? posted by zuki on September 9, 2006 at 12:03:37:

High definition has to do with the resolution of the picture and refers to either a 720p, 1080i, or 1080p signal. All of those signals also use a higher pixel count than standard definition pictures so, as a result, you get a lot more information refreshed more often. Basically, the difference between standard and high definition is simply the amount of information defining the picture and sound. High definition gives you better quality because more information is used to build the picture/sound.

Component video is both a standard defining the way the picture information is 'encoded' for transmssion from a source to a display, and also a cable standard which defines the connection between source and display. At the stage the component video standard was developed, all TVs were analog and the component video signal is therefore an analog signal. You can transmit both standard definition and high definition picture information by component video.

HDMI is a cable/connection that is intended to transmit the same information that a component video connection transmits, but to transmit it in digital rather than analog form.

So, if it's the same information, why should one have an advantage over the other? Basically because, if you send a component video signal from a DVD player or digital TV tuner to a digital display device like a plasma or LCD screen via a set of component video cables, the player/tuner has to convert the original data, which is in digital format, to analog form for the component video cable connection and the display device then has to convert that analog signal back to digital form to drive its display. Keeping the signal in digital format the whole way, and avoiding those 2 conversions from/to digital should work a little better in principle but, as usual, everything depends on the quality of the execution.

David Aiken