While many consumer electronics sold today come with Wi-Fi adapters, most electronics still require some type of physical cable to connect to other home theater equipment. For many years, the standard connector for VCRs, DVD players, and video game consoles was the composite cable, which transmitted a video signal over a single analog channel. However, the composite cable faces an uncertain future in a world of high definition content and the need for increased data bandwidth.
Composite cables sold in stores typically come attached to two audio cables, so many consumers mistakenly believe that all three cords are composite cables. The yellow cable is the only composite cable out of the three, and it is used to transmit a video signal from a TV receiver, VCR, or other device to the television.
It can transmit video up to 480i resolution, making it unsuitable for any sharper image. The “i” and “p” after the number refer to interlaced and progressive respectively. Interlaced video updates every other line of pixels with each screen refresh while progressive video updates the entire image with each screen refresh. Progressive video appears sharper with crisper movement.
Most DVDs are 480p, and they will be converted to 480i over a composite cable before being resharpened by the television. Unfortunately, these two conversions will slightly degrade video quality from its initial 480p resolution.
Composite cables typically come bundled with two RCA cables to transmit audio. They are identical in appearance to the yellow composite cable except in color. The white cable is used for the left audio channel while the red cable is used for the right audio channel. Because the two RCA cables are limited to stereo sound, they are unsuitable for surround sound systems with at least three distinct audio channels.
How to Connect
To connect composite and RCA cables, plug the cable into the socket that shares the same color. Most devices will feature a set of three distinct sockets that are labeled “Video In” or “Video Out.” Other sockets will be clearly labeled “Component” or “HDMI” to eliminate any confusion.
The video and audio cables send independent signals, so a home theater enthusiast could hook up the yellow video cable to the television while connecting the white and red RCA cables to another speaker system. Similarly, the white and red audio cables can be used by themselves to play audio CDs.
Like most home theater cables, composite cables are identical at both ends. Either end of each cable can be used in the “Video In” and “Video Out” ports.
The High Definition Future
Composite cables are only capable of transmitting 480i video signals with stereo audio. However, most televisions sold in the past five years support much higher resolutions. DVDs run at 480p resolution, but most high definition television signals air at 1080i resolution. Relatively new Blu-ray discs use an even crisper 1080p resolution.
That’s not to say that these types of media can’t use composite cables. Composite cables can transmit video and audio signals from DVDs, HD television channels, and Blu-ray discs. Unfortunately, all of those video signals will be capped at 480i.
To get around this problem, consumers can pick up component or HDMI cables. Many computers also support DVI cables. Component, HDMI, and DVI cables all support a variety of resolutions from 480i up to 1080p, and HDMI cables can transmit both video and audio signals over the same cable.
If composite cables are technically inferior to newer cables, why use them at all? On one hand, many consumers still own older equipment like video game consoles from fifteen or twenty years ago. VCRs and camcorders can both use composite cables without reducing picture quality.
Composite cables are also convenient. They slide snugly into the socket regardless of orientation. HDMI and DVI cables both fit into their sockets at one specific angle. Component cables typically aren’t as clearly marked, and the stiff cables can be difficult to twist and fold around in tight corners. In contrast, composite cables are inexpensive and easy to connect, and for older equipment, they can’t be beat.