The Video Connector Guide for Churches

Written by Anthony D. Coppedge, Church Media Consultant

“Hey, pass me that 75 Ohm cable with the five female BNCs so I can hook up the RGBHV to this five-wire VGA cable to the projector”.

If you were lost on “75 Ohm”, read on: comprehension is but a few paragraphs away. This article will help you understand how to “talk tech” and know your BNC from your VGA.

 Let’s start with the bottom of the “video food chain” and work our way up.

RF Video

This is the cable that goes from your cable box or TV antenna into your TV. It has a circular end (called an “F connector”) and a very thin wire sticking out of the middle that thread onto the TV input.

This cable carries an “RF” signal. RF means Radio Frequency, and it means that the signal can pass through the air (which is how a TV antenna can pick it up). It also means that it’s been modulated, whereby hundreds of TV channels can come in on one cable.

The downside to this technology is the quality. It’s not bad on a 32” TV, but if you project it onto a 9’ x 12’ screen, it doesn’t look so good. Your TV, VCR and Cable boxes all accept this input type because they each have a modulator built in that lets them pick which channel to show at any given time.

You can make your own in house cable TV system by using an RF modulator and running various sources to different TV’s throughout your facility.

Composite Video

Most people recognize the “yellow input” on their VCR or TV as the video input. This type of jack is called an RCA jack, and the yellow, white and red cables are called RCA cables. The yellow jacketed cable is the video cable, and carries composite video. Composite video is very much a consumer-grade signal, and lacks the sharpness and color available on more expensive equipment. However, it’s also by far the most common video type, and therefore used quite a bit in churches.

Composite video in the United States is based on the NTSC (National Television Standards Convention) signal format. If you go to Europe, there are two other prominent formats, PAL and SECAM (which, by the way, are all incompatible with each other). This is good to know if a missionary brings back a tape recorded on European or South American equipment.

But composite video also is available on another type of connector: the BNC. BNCs are the professional’s choice of connectors because they don’t pop on or off; they actually lock into place, preventing accidental cable pulls. When composite video is carried on a single cable with a BNC connector, it looks the same as when it’s connected with an RCA adaptor; only the ends are different.

S-Video

Back in the 1980’s, the term Super Video came into popularity, and it was a marked increase in quality from the composite video of the previous 30+ years. S-video takes the NTSC signal and separates it into luminance and chrominance. Luminance is the basic picture and sync information, and Chrominance is the color information. This is why a black and white TV can show a color TV program: the Chrominance is disregarded.

S-Video typically used a 4-pin connector and a special S-video cable that only connected one way (which is usually denoted by an arrow on the connector). The higher quality picture was worth the clumsy connector, and people got used to it.

The professionals, however, still liked their BNC connectors, and used a two-wire cable to run S-Video into two BNC’s (still Chrominance and Luminance). Both the BNC two-wire and the S-video 4-pin cables carry the exact same signal.

Component Video

Component means that each part of the signal is separated into individual signals for maximum quality and bandwidth. It used to be that only professional broadcast equipment used component video, but the DVD player changed that. If you use a DVD player, use the component video outputs if your projector or monitor supports a component video input.

Consumer component video still used the familiar three RCA connectors. Most DVD players use either the Y, Pb, Pr connection type of the (less common) Y, Cb, Cr. Y is the luminance channel and Cb and Cr are the chrominance or color-difference channels.

Many professional VTRs (Video Tape Recorders) have Y, U, V or R, G, B component video inputs, and they’re usually on three BNC connectors, though some use a Phoenix connector (not shown).

Component video, to the eye, is exponentially better looking than S-Video and Composite Video. This is obvious when you watch most DVDs; the pictures are typically sharper, the colors richer and have a much better grey scale.

Finally, many projectors don’t have the three Y, Pb, Pr inputs available as RCA or BNC connectors. Instead, they let you use one of the VGA (HD-15 pin) inputs, like your computer would use, by using a special “fan-out” cable that takes either 3 or 5 BNC/RCA inputs and converts them to a VGA (HD-15) male connector. Check the specifications on your projector or switcher/scaler (if you have one) to see if this option is offered.

SDI

SDI means Serial Digital Interface, and it’s the standard digital format used on broadcast-quality equipment. SDI is capable of carrying large amounts of data over a single cable, it crosses the line from video to computer resolutions by actually sending digital video (either compressed or uncompressed) over the cable, maintaining a perfect picture.

SDI is not found on consumer level equipment, but it can share the same cable and connector (BNC) type as Composite Video.

RGB (VGA)

Projectors, monitors, desktop computers and laptop computers have used the HD-15 VGA connector for years. The little pins on the end of the cable (usually male) are housed in a protective cover that mates quickly to the 15-pin port (usually female). Simple and reliable, these cables are capable of carrying quite a few signal types. Most common are the computer resolutions from the desktop or laptop PCs or Apple computers.

Each computer resolution is represented in both horizontal and vertical lines of information. So an 800 x 600 resolution signal (called SVGA) can just as easily travel on a RGB cable as a 1,280 x 1,024 resolution signal (called SXGA). The difference is bandwidth. Bandwidth is the amount of data that can be moved. SVGA uses much less bandwidth than SXGA. Therefore, SVGA signals can travel further (without noticeable loss) over a RGB cable than an SXGA resolution signal.

Again, the professionals ducked their head in and wanted a pull-proof connection, so the BNC made its way into the RGB realm with a five-wire cable. This type of cable is called a RGBHV cable. Red, Green, Blue, Horizontal Sync and Vertical Sync are all present, at a component level, on this type of cable. Many of the larger (installation grade) projectors offer both VGA (HD-15) and RGBHV connections, and most video scalers and some switchers also opt to use the RGBHV BNC connectors.

FireWire

Computer data has been sent by VGA – carrying visual display information – for quite a while. But the need to carry video content, such as that found on Composite, S-Video and Component Video, into a computer has become necessary as computers have become exponentially faster and easier to use.

Firewire is more accurately called “IEEE 1394”. IEEE is the abbreviation for the Institute of Electrical and Electronic Engineers, the standards body controlling the specification for this technology. 1394 is the sequential number of the specification, as 1,393 standards had already been considered. Apple actually owns the name “FireWire”, and Sony dubbed it i.link. But don’t worry – it’s all the same thing.

FireWire can handle up to 800 Mbps (megabytes per second), making it an ideal transport for large files, such as video. In addition to carrying video and audio, though, FireWire cables can connect between a video camera with a FireWire port and a computer and act as a remote-control cable to the camera. This means you can rewind, play, fast forward, stop, pause and even eject the tape from the camera right from your computer (if you’re using non-linear editing software).

DVI

Digital Visual Interface, as it’s sometimes called, comes in two types: DVI-D and DVI-I.

DVI-D is the digital-only format that connects a digital device (such as a computer video card with a DVI output) and a fixed-matrix digital display device (such as an LCD monitor, Plasma monitor or LCD/DLP/D-ILA projector). The exact output is matched to the exact same display type, resulting in a one-to-one ratio exchange of information. The downside to this technology is that only one resolution can be displayed at a time, and at one refresh rate. This applies more to dual-monitor setups on computers or plasma video-walls, but the limitation is there.

DVI-I also has extra pins on the cable and connector to also handle an analog signal. This means that a DVI signal can still be perfect, but it also means that analog monitors (such as CRT’s) can still be sent analog data.

There’s also a severe distance limitation to DVI (about 12 feet), so it’s not an option for long cable distances.

Summary

The various connections and cable types also mean you have to know about signal compatibility. Often, it is necessary to change inputs at the projector to view the different signals. This can be distracting, so churches should at least consider purchasing a switcher with a scaler that reformats each input to match one output that is sent to the projector.

Your application will determine the right signal type for your church, but keep in mind that you should try to use the best quality connection available to maintain the best possible video image.

Finally, be sure to print out and review the Church Video Connector Quick Guide. This handy reference guide has a picture of the jack (connector) and cable, the name of the signal, where it can be found, and the level of quality you can expect from the signal and cable.

Anthony Coppedge provides consulting to Churches for developing a media ministry and choosing the right equipment, Manufacturers for developing new products and marketing strategies to reach the church market and Dealers for sales training and systems integration development for working with churches. He lives in Bedford, Texas with his wife and two daughters. Visit his Web site at www.anthonycoppedge.com

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