Component Video Cable vs. HDMI Cable
While both cable formats present a picture as essentially a mosaic of red, green and blue color components, the way they do this is based on two completely different processes. For component video cable, three individual inputs are needed; the signal is usually referred to as YPbPr. The “Y” component focuses on the brightness of the image as the “green” channel, the “Pb” component is the blue channel, and the “Pr” component presents the red part of the picture. All three signals are then put together to create the final picture.HDMI Cable, on the other hand, uses a standard called Transmission Minimized Differential Signaling (TMDS). What this basically does is incorporate three different channels for each color set, allowing one cable to sync all the channels together in a straight-to-digital format. Component cables typically take a digital signal, convert it to analog for internal conversion processes, and then convert it back to digital for output to the TV. The resting assumption is that, because of the digital-to-analog-to-digital mechanism involved with component cables, there’s always a bigger loss of picture quality. That sentiment is ridden with naivety, though, because HDMI suffers similar issues. Even though it’s a digital format, it’s hardly a universal conversion from every single output source. HDMI cables also need to convert signals to their own format. The only difference is that it’s just messing around with conversions between different digital signals instead of digital and analog. In other words, the stuff that’s going on inside these crazy cables is whacked, no matter what kind of cable you’re using. While it’s an easy cop out to just assume a more antiquated analog format will have more trouble reproducing a purely HD image, that statement lacks thorough consideration. HDMI has also been panned because it’s much easier for the signal to degrade over time. Long-range HDMI cables are also known to lose quality because of a less-than-perfect set of standards for the format. Analog cables, on the other hand, can last decades and stretch for dozens of feet without any sort of automatic degradation. Because of its universality with one single input for audio and sound, HDMI has become the much preferred standard for HDTV hook-ups. That doesn’t mean it necessarily has a huge leaps-and-bounds advantage over component, though. Component video provides a more reliable picture, carries a more robust set of standards and generally works better for long-range professional-type set-ups. It should be noted that the other major high definition video standard, DVI, runs with the exact same technology as HDMI, except it does not carry audio. Your HDTV may have DVI inputs instead of HDMI, and everything written here about HDMI video is the same for your video signal.
The real point is that there’s not really a winner: the argument to be made is that both formats function just fine. HDMI is nice because it incorporates both audio and video, and that’s a very nice extra feature. However, if your cable company’s HD converter box only supports component output, that’s not a reason to jump to another service provider. Analog technologies date back decades upon decades and are built on a long-standing tradition. And while digital formats are supposed to deliver more fulfilling standards, they’re often under-utilized in favor of making cheaper products.