Video Cable Comparison

Video cables used to be simple, there was only one type. However with new television technologies coming out constantly these days video cables are growing ever more complex. I hope to explain the differences between various cables and what they may provide for you. A final note, even though most of these video cables are used world wide, I will be covering the American Television Standard, NTSC (National Television System Committee).

A Brief History

At the start of Television, there was no video cables, there was an antenna that connected to your TV via a spade lug that connected to screw terminals to the back of your TV. Depending on how close you were to the TV station, you may receive a nice sharp picture or a grainy picture.

In the 70's came Cable, not only could you get a sharper picture when compared to antenna, you could get many different channels, and the quality was consistent. The signal came from a coaxial cable that screwed into the back of your TV. If you had a home made Coax cable, the picture could bleed or cut out all together. Professionally made cables provided a better signal, though a good home made cable could certainly hold its own against a professionally manufactured cable. The better cables had gold plated connectors to provide protection against corrosion.

The late 70's and early 80's produced in mass market a device that would change how your TV was viewed, the VCR. Even though the technology had been out for a while, it did not make it to mass production until the 70's and 80's. The first VCR's just used a standard Coax cable that feed the coax used for cable into the VCR and another coax feed out from the VCR to your TV.. Consumers wanted something easier to use, so then came the advent of Composite cables.

A composite cable is a Video cable that has RCA connector jack at both ends. The cable is easy to plug in since there is no screwing as with the Coax. The user simply pushed the composite cable into a connector on the back (or sometimes front) of the TV. No more having to pull your TV out and unscrew a coax cable every time you wanted to switch to a different video device.

In the 90's there was a demand to have better video quality than a composite cable could provide. A engineer realized that if you separate the various types of video signal instead of feeding the entire signal through a single connector, you could get a better quality video, thus came the advent of the S-Video connector. S-Video provides through a single cable, 4 signals that when separated give a better quality video. The cable was simply plugged into a TV with a S-Video connector and Video quality was improved.

Digital TV came in mass production in the late 90's. Along with it came a host of differing cables, that gave an extremely sharp picture. The cables varied greatly and do give a slight difference in Video quality, that is measurable even if slight.

A simple guide to video cable quality

Video cables from worst to best

1. Composite








2. S-Video








3. Component








4. HDMI / DVI

Simple as that, you see the same on many different displays in stores. Let's go into detail why though.

• Composite

Identification. Composite is a Video cable often identified by a yellow colored boot over and a RCA jack at both ends. Sometimes this cable is binded together with a red and a white boot and RCA jacks at both ends.

This video cable sends the video all through one connector, the red and white connectors are used for audio.

Advantage: It is easy to plug into your television and most televisions support this type of connector.

Disadvantage: Out of the four commonly used Video cables provides the worst signal.

Notes: Composite video combines the 3 types of video signal used for an analog video. These signals are commonly known as Y/U/V. Y represents the brightness or luminance of the video and the video, it is also used to send the synchronizing pulse. U and V are used to carry the color information also called chrominance.. The signals are all combined or modulated at the video device (DVD, VCR etc) and sent over the single composite cable. When the signal reaches the Television, it will separate theses signals and apply them to show video. Having to combine and then separate the signals again, means that there is a loss of video signal quality.

• S-Video

Identification: S-Video is a Video cable often identified by a dark gray or black boot, covering over a miniature DIN (barrel style connector with recessed pins) at both ends.

S-Video has 4 pins used for video. Each one of these four pins separate out one part of a video signal.

Advantage: A better video quality than provided by composite.

Disadvantage: more difficult to plug in and remove. Connectors can break easily. Not quite as good as component video.

Notes: S-Video was developed to improve some of the problems encountered with Composite Video. By separating out the various video signals and combining them into one connector, the video signal is improved considerably. One of the pins is used to carry luminance (Y) which includes brightness and the video. A second pin is used for grounding the luminance signal. A third pin carries the color signal, a modulated chrominance (UV) signal. The fourth pin is used for grounding the chrominance signal.

With two of the three signals separated a considerably improved video signal is readily seen,.

• Component

Identification: Component video is three separate Video cable that has RCA jacks at both ends. The cables are usually separate, but not always so. The boot at the end of each RCA connector are colored Red, Green and Blue.

Advantage: By separating out each of the video signals onto a different cable, video quality is improved over S-Video.

Disadvantage: Not quite as good as HDMI, though it is close. Three separate connectors to plug in.

Notes: Component video separates out the colors as opposed to S-Video which separates out the signals. Component Video cables are associated with HD-TV. When you look at the ends of a component video cables, you would assume that the colors are carried in Red/Green/Blue signals. However the signals are known as Y (luma) , Pb(blue difference and luma) and Pr(red difference and luma). Y,Pb,Pr are for analog signals. It also may be known as Y (luma), Cb (blue difference and chroma) and Cr (red difference and chroma) for digital.

A bit of explanation is needed for Luma. Luma is brightness just like Luminance, however the brightness described with luma is colorless. Luminance describes the brightness of the colors.

Y is the luma signal. Pb is a luma signal plus the blue difference from the rest of the signal. Pr is a luma signal plus the red difference from the rest of the signal.

For a digital signal, the connectors are known as Y (luma), Cb (chroma plus blue difference) and Cr.(chroma plus Red difference). A bit of explanation is needed for chroma. Chroma describes the difference from gray at a given hue and lightness

Y is the Luma signal. Cb is a luma signal plus the blue difference from the rest of the signal. Cr is the luma signal plus the red difference from the rest of the signal.

• DVI

Identification: DVI connectors are small rectangular connectors

Advantage: A pure digital signal provides the best video quality.

Disadvantage: More expensive than other video cables.

Notes: DVI cables and connectors are for a digital signal, thus provide the best video quality. They are found on an increasing number of high end televisions and mid level televisions. The signal carried on a DVI cable is associated with HD-TV and provides the best picture to a HD-TV. DVI connectors are found on cable receiver, computer video cards, DVD players and Televisions. However, sometimes one may find that the device may have a different connector than the television. I.e. Your cable receiver may have a DVI and your television may have a HDMI. No problem, converters are available to change the connector.

• HDMI

Identification: HDMI connectors are small rectangular connector that taper at an angle on both ends for polarity purposes. The connectors are smaller than a DVI connector.

Advantage: A pure digital signal provides the best video quality.

Disadvantage: More expensive than other video cables.:

Notes: HDMI cables and connectors are for a digital signal, thus provide the best video quality. They are found on an increasing number of high end televisions and mid level televisions. The signal carried on a HDMI cable is associated with HD-TV and provides the best picture to a HD-TV. HDMI connectors are found on cable receiver, computer video cards, DVD players and Televisions. However, sometimes one may find that the device may have a different connector than the television. I.e. Your cable receiver may have a DVI and your television may have a HDMI. No problem, converters are available to change the connector.

As you may see, DVI and HDMI have the exact description in the notes section. There are not many differences between the two that effect the video quality that one can perceive visually. If your cable receiver has a DVI, but your Television has a HDMI, don't fret, just purchase a converter.

The difference between a component video cable and HDMI/DVI cable is small, but it is still there. If you are viewing the television from up close, you may see a difference, from a standard viewing position, you will probably not notice a difference between the two.

Display Capacity Of Various Video Cables

• Composite Video - Capable of 480i, maximum resolution of Standard Definition TV (SDTV). 480i means 480 lines of resolution in an interlaced format.








• S-Video - Capable of 480p, maximum resolution of Enhanced Definition TV (EDTV) and 480p (SDTV). 480p means 480 lines of resolution in a progressive format.








• Component Video - Capable of High Definition TV (HDTV) at 720p, 1080p and 1080i, EDTV at 480p and SDTV at 480i.








• HDMI and DVI - Capable of High Definition TV (HDTV) at 720p, 1080p and 1080i, EDTV at 480p and SDTV at 480i. Resolution is sharper than component video.

I hope that this article helps you with the selection of your video cable. One final word of warning, be wary of ultra - premium cables. Sometimes the only thing you are purchasing is the name brand of the cable. Be way of no-name cables as well, you may get an inferior cable

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