Tuesday, October 16, 2007

HDTV Video Connections or why is everyone fat on my TV?

Part II

VGA and component are analog sources of high definition signals. Analog HDTV signals were first introduced on computers, satellite/cable set-top boxes, VCR and high-end DVD players. The picture quality was superior over composite or s-video, which is not capable of HDTV resolutions. VGA, some times called RGB, is a small format 15 pin, three(3) row connection used on most computers for connecting your monitor and gave us our first view of high resolution video. You will also find these connections on HDTV monitors designed to accept computer standard video and frontal projectors.

Component is a very popular HDTV connection using three (3) cables labeled YpbPr and distinguished by the familiar three (3) colors red, green and blue connectors found on most consumer electronic equipment. Connecting component is simple and trouble free for 480, 1080i or 720P HDTV installation plus the connection of choice by installers. However, the newest HDTV format 1080P is generally only available over a HDMI connection.

Here is where the confusion starts. VGA from a computer is capable of many resolutions, but the standard computer display resolutions are not compatible with HDTV unless the TV monitor can accept computer resolutions over VGA. If you purchase a VGA to component cable or BNC, to connect your computer to a HDTV that is component, it will not work. These cables are for special purpose applications.

For example some older Mitsubishi, Pioneer and other HDTV ready monitors sometimes used the same VGA connector called RGBHV and accepted the signal through five(5) RCA or the professional equivalent BNC connection at HDTV resolutions. These HDTV monitors require a converter box to convert component HDTV to these inputs.

Now you understand why there is so much discussion over the best installation method and if you need a converter from VGA to component and component to VGA. The converter boxes have electronics built in to take the horizontal and vertical sync signals in VGA and convert them to component or RGBHV or if you are going the other direction. Most are confused and for good reasons.

Quiz time! If component is sometimes mis-referred to as red, green and blue what is the HV in RGBHV?

Oh no, that is not the end of it. If the VGA resolution, from a computer source, is not a HDTV standard resolution of 480, 1080i, 720P and now 1080P, a simple VGA to component converter will not pass a picture compatible with the display. Most computers are not HDTV resolution outputs. What do you do now? Look at our PowerStrip user guide for one option to force your computer to a HDTV resolution, but this is not for the faint at heart. Read the entire article before you decide to try it. http://www.ramelectronics.net/html/powerstrip.html

Your best option is an external scaler.

Are you lost yet? Well let throw one more at you. Some displays, projectors, and HDTV’s use the VGA, 15 pin, three (3) row PC connector for both RGBHV and component signals. So how do you know?

  1. First, frontal projectors with VGA will also accept component to save space.
  2. If a VGA to component cable fails to yield a picture then you need a converter.
  3. To save space some converters use VGA connectors for both signals to save space.
  4. Read the equipment manual, it will tell you what signals will work over the VGA.
  5. This is why VGA to component cable exist, but seldom work unless on a frontal projector or special application!

Finally, we stated that component connections are only HDTV resolutions and VGA has multiple PC resolutions. Check out this Wikipedia link on all the resolutions and picture geometries options. The visual graphic array is just, exciting.


Stay tune for part III as we look at scalers and other HDTV switching options.

1 comment:

  1. This HDTV video is very stagger.


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