Connecting Video Equipment

Connecting Up Your Equipment

Updated 10/04

This page contains mostly legacy information. If you have a TV set or other equipment that does not have HDMI jacks or other digital inputs and outputs, then you may find this information useful.

If you want convenience and ease of use you must be prepared to give up some picture or sound quality.

Conversely if you want the best picture and sound quality, your home theater will be more complicated to operate.

And if your equipment is not top of the line, you will have to give up both some quality and some convenience. It is very common to not have enough places in back of the TV set to plug everything in and then you have to use switch boxes or your VCR to help connect things together.

For many home theater owners, having to pick up three remote controls, --for the TV, for the stereo system (audio/video receiver) and for the VCR -- will continue to be necessary.

The jacks and cables used with DVD players don't fit all TV sets. If your TV set does not have a jack labeled "video in" or S-video, try plugging the DVD player into the A/V in, camera, or video in jack of your VCR. If you get a jittery picture on some disks, you may need an "RF modulator" costing about $30.00 (US) and obtainable from Radio Shack. This connects between the DVD player and TV the same way as the VCR..

Video Glossary

Audio/Visual Receivers (7/98)
A/V Receivers, Component vs. S-video
A/V Receivers, Multiple TV Sets (8/98)
A/V Receivers, Picture Quality Loss
A/V Receivers and Laser Disks
A/V Receiver and TV Without Video In
Bandwidth and HDTV Requirements (3/00)
Can't Record With Power Off
Boosters and Splitters
Cables
Audio Cables for Video? (3/00)
Speaker Cables (10/01)
Connecting Your ...
Cable TV Tuner Box
Camcorder
Combo -- DVD/Laser
DVD Player
HDTV Set Top Tuner
Laser Disk Player
Satellite Dish Tuner
VCR
(no video jack?)
DVD to TV Antenna Terminal (older TV)
General Rules for Connecting Up Equipment
Laser Disk Players Requiring S-Video
Progressive Scan TV Considerations (9/98)
NTSC Program to PAL TV, etc. (9/98)
Understanding Encoding and Decoding
Make Sure All Jacks Work (7/98)

More on bandwidth, click here.

Two TV Sets, One Composite Only

I have seen at least one computer bulletin board article about using one A/V receiver to feed two TV sets, one using the composite video output and the other using the S-video output. There are numerous limitations:

1. You cannot watch two different programs on the two TV's.

2. If the receiver does not feature cross feed, the composite sources (VCR, LD) will play only on the TV set with the composite connection; the S-video sources (DVD) will play only on the TV set with the S-video connection.

3. A laser disk player with an S-video jack should not take advantage of cross feed to the A/V receiver composite output. Instead it should commandeer two of the receiver input slots, one for S-video and one for composite video. Significant picture quality loss occurs at the TV set where the overall cabling path was S-video from LD player to receiver and composite from receiver to TV set.

4. Picture quality loss also occurs if the cables are too long. Follow the recommendations of the A/V receiver manufacturer.

TV with antenna (RF) jack only.

One possibly confusing detail about audio/visual receivers

When you are viewing TV broadcasts using the channel selector on your TV set, the video signal is processed entirely by the TV set while the audio is taken from the TV set and fed to the A/V receiver and then output to your stereo speakers.

When you are using video sources connected to your A/V receiver, the video signal travels from the A/V receiver to the TV set. The audio from the video device goes to the A/V receiver and then to the speakers without going through the TV set.

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Loss of Picture Quality Using A/V Receiver

See, also, Bandwidth.

Some viewers hook up DVD players (and other S-video or component video devices) to an A/V receiver that feeds the signal to the TV using only a composite video cable. Loss of picture quality will always occur since somewhere, either in the DVD player or in the receiver, the signal has to be converted to composite. Here the signal from the DVD player is handled for convenience only as opposed to handled correctly. Sometimes the viewer has no choice, the TV might not have an S-video jack, or the S-video jack cannot be used if it is also necessary to use the composite video in jack.

All of the enhanced picture quality associated with S-video or component video is lost if the signal is converted into composite video even if the only reason is to go through a standard video cable. Most of the loss occurs during the mandatory conversion back into S-video, performed by the comb filter in the TV. However the final picture quality is no worse than if the program was transmitted or recorded in composite video to begin with.

A TV set can theoretically accept any of the common signal formats, S-video, composite video, etc. if only it had the appropriate jacks. A TV broadcast signal is a composite video signal modulated as a TV channel. After processing by the TV set tuner it becomes pure composite video. Next it is decoded into S-video by the comb filter (or a cheap substitute). Then it is decoded via the color decoder into a component video format similar or identical to what DVD disks are recorded in, depending on the TV set make and model. Finally the signal is decoded into RGB, separate red, green, blue signals that feed the picture tube. All TV (receiving) sets must have all of these circuits. If a video device outputs a component video signal (DVD players do), then that signal should, if possible, be fed directly into the TV set's component video circuits for a much higher quality picture. Whereas if you must include a composite cable anywhere in the path from program source video device to TV set, the signal has to be converted into the composite format using a variety of electronic circuits first, and be digested back into component video in the TV set in the manner I described. The more circuits there are in the signal path, the greater possible loss of picture quality can occur with the comb filter as the biggest detractor.

A component video signal can be encoded into S-video for less picture quality loss than composite video encoding (but still some). This might be done in order to feed a TV set or A/V receiver with S-video but no component video jack. Once in the TV set, the signal skips the comb filter but still has to go through the TV set's color decoder. Many viewers won't notice any quality loss. Most DVD players contain the encoding circuits so you have a choice of getting component video, S-video, or composite video output. Serious videophiles will make a direct component video connection if at all possible.

TV broadcasts and most cable programs are already in the composite format so their video signals must go through one comb filter anyway. The best picture quality that can ever be derived is that after decoding by the comb filter and other circuits mentioned above.

A/V Receivers -- Special Program Source Considerations

Special note about laser disks

Don't use the S-video output of a laser disk player with an A/V receiver hooked up to your TV set with a composite cable, either as the only feed or as a cross feed. This results in double back and forth conversion between composite and S-video and considerable quality loss. (LD is composite to begin with; the LD player converts to S-video to go out that jack, the A/V receiver converts to composite, and the TV converts back to S-video.) Use the composite output from the LD player instead.

You may find that the difference is so slight that the convenience of using all composite video connections via a composite only A/V receiver outweighs the advantage of S-video direct to the TV set skipping the A/V receiver.

Special note about camcorders and VCRs

If an S-video (sometimes labeled S-VHS) jack is provided, use it if you can. Click here for more details.

Cannot Record Using VCR With Receiver Powered Off

If you can use a remote control to operate your A/V receiver, that is a dead giveaway the receiver must be powered on to use any device, including a VCR doing unattended taping. All of the switching is done electronically. A few receivers use relays rather than electronic switching. Relays leave a few connection paths in effect with the power off but there is no easy way of knowing that the paths with the power off are the paths you want. Also relays are "less reliable" then electronic switching, they have metal contacts that can get "oxidized" giving you an intermittent picture or jitters.

Your receiver may also have amplifiers or pre-amps between the incoming video signals on their way to the VCR. They, too, need power. The amplifiers boost marginal signals in order to reduce snow in the picture. They may also correct the problems caused by long cables, although how well the amplifiers do this varies from one brand of receiver to another.

You can try routing DSS and cable TV through your VCR before going to the receiver. This means you don't have to turn on the receiver to record but you may have to turn on the VCR to view DSS or cable programs. Connecting a program source directly to the VCR assures the best recording quality provided you don't keep moving cables back and forth which will eventually loosen up the jacks and cause jitter. The VCR should not degrade the quality of signals passing through but it is a good idea to check anyway. Spend at least a week observing picture quality and comparing it with going through the receiver first. Any degradation is likely going to be subtle.

Before Buying a Big Screen or Upscale TV

Make sure you can connect things to and select for viewing each of the various inputs -- S-Video, regular video in jack, etc. with all jacks occupied at the same time!

To prove this, have the salesman connect disk players, VCRs, etc.*, etc. to all of the jacks and use the TV remote control or knobs on the front of the TV to select each of the program sources in turn.

I have heard of the problem where you have to crawl around back and unplug your DVD player from the S-video jack before you can even use your laser disk player plugged into the composite video jack. This is probably true if the TV remote control has only one selection for "A/V". Plugging something into one jack blocks off another jack.

Inability to use all of the jacks simultaneously is a big deficiency nowadays (continuing into 2001) because different program sources work best plugged into different jacks.

Even if you have or plan to buy a video receiver or switching system, you may still find it better to connect some of your program sources directly to the TV to avoid using composite video connections.

Oh, by the way, a component video jack is desirable to have on a big screen TV.

* If one DVD player has all four kinds of output jacks (some do), you still need to conduct this test with a different device, with a different program playing, connected to each jack behind the TV.

About Cables

Cheap cables are not always bad, rather their quality is less predictable. One might be very good while another of the same make and model causes snow, discoloration, loss of detail or even a jittery picture. Performance degrades with greater cable length. I would guess that with top quality cables you can get away with cables one and a half times the maximum length recommended by the player or receiver manufacturer. With cheap cables, you will probably get good performance if the cable is no more than half the maximum length recommended.

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Audio Cables for Video? (3/00)

Q: Can I use an inexpensive audio/video cable set to connect the three component video jacks of my DVD player to the TV?

A: You may get a picture but likely of poor quality. It depends on the quality of the audio cables in the set, which can vary widely. The answer is really complicated but we can start off simple. Use the yellow (video) cable for the Y (green) jacks and the red and white cables for the red and blue jacks, respectively. If the picture looks OK, you can get away with it.

For manufacturing simplicity, all three cables of the set might be of the same quality in which case the cable set will work perfectly well for component video. But more likely the two audio cables are of a lesser grade which may cause some smearing or softening of the picture or allow noise to contaminate the video signal causing snow.

Many viewers won't notice anything wrong with using audio cables particularly if they are only six feet or so long. But when playing a test disk such as Video Essentials, deficiencies may show up that are time consuming to pin the blame on the TV or the cable.

It is usually difficult to tell the grade of the cable just by looking at it. You have to rely on the package description or advertising. Using audio cables for video is a deliberate attempt to buy a lower grade cable. The important characteristics are quite technical in nature, impedance (75 ohms needed) , shielding, and bandwidth. The yellow (video) cable in an A/V cable set is typically the same grade as the green (Y) cable in a real component video cable set of the same grade.

Here are the bandwidth requirements for the entire video signal path, restated:

Audio: 20 KHz.
Ordinary composite or component video: 7 MHz.
Progressive scan component video or RGB 14 MHz
HDTV: 37 MHz. (For today's TV sets you can get away with 22 MHz for 1080i but you really need all 37 MHz for 720p.)

The Pb and Pr signal paths need half the bandwidth stated above. For RGB, all three signal paths need to have the full bandwidth.

We recommend cables with at least two to three times the system bandwidth desired.

Speaker Cables

Determining the maximum length of speaker cables of a given thickness is complicated and takes into account the speaker impedance, the amplifier output impedance, and amount of power involved. Instead, experts just publish some watered down figures such as these:

The first figure for length is a suggestion made in Home Theater Forum, the second figure is my own suggestion.

Up to 10 (15) feet: 16 gauge
10 to 20 (15 to 30) feet: 14 gauge
Over 20 (30) feet: 12 gauge

Aside from the thickness, there is no advantage in buying more expensive cables except if they are prettier looking or if they have, already attached, banana plugs or other tips that fit on the amplifier or speaker terminals better.

You can get relatively inexpensive speaker cable at stores like Radio Shack and Home Depot, and cut it to the lengths you need. It is sometimes more convenient to buy just one spool of 12 gauge "lamp cord" or speaker cable as opposed to some of each gauge for different needed lengths.

Try to get speaker cable either with a ridge running lengthwise down the outer cover, or with a transparent cover where one of the wires is silver in color. Otherwise it is difficult to figure out which wire is which for speaker phasing. Even lamp cord usually has one of these features.

Try to get stranded wire, which is less stiff and therefore easier to work with compared with solid wire.

About Switch Boxes for Video

These can be used if you run out of jacks on the back of your TV set.

You can hold off buying them until you need them.

They may come in handy for S-video and/or component video devices connected directly to the TV set. Usually a switch box for video does not also control the audio so you will have to select the audio separately using your A/V receiver (or using another switch box).

A Y-connector is not a good substitute for a switch box or a signal splitter. The cables going to the other devices and the electronics in the other devices, even if turned off, can degrade the picture quality. If several devices connected using a Y-connector are all turned on, the spurious signals that they always emit will travel through the Y-connector and degrade the picture quality for all of them.

Encoding and Decoding, Less is Better

In a Nutshell

The various jacks on the back of the TV, VCR, disk player, etc. stand for the same video signal in a variety of different formats, such as S-video, composite video, etc. Each signal format is an encoding or a decoding of one or more of the others. The goal is to choose cabling methods so that a minimum of encoding and decoding takes place. Every encoding and decoding maneuver requires additional electronic circuits that may detract from the picture quality.

Frequently asked question: How do I get from a regular video out jack to an S-video in jack? Answer: Normally this is not done but if you must, you need a box containing some circuits;. The $500.00 Faroudja Video Enhancer is one such box and it contains a comb filter. Cheaper boxes contain a notch filter identical to that in TV sets without comb filters and that limits your horizontal resolution to about 260 lines.

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A video signal is encoded to facilitate the transmission from one component to another (for example from broadcast station to your TV set). Once in the TV set, the signal must be decoded back to RGB (red, green, blue components) for display on the picture tube. Every TV set has all of the necessary decoding circuits whose quality of course varies with the price of the TV.

These are encodings

From RGB to Y, R-Y, B-Y component video (Y/Pb/Pr; Y/Cb/Cr; YUV, or to YIQ)
From component video to S-video (Y/C)
From S-video to composite video* (RCA video in/out jacks)
From composite video to RF (a TV channel)

These are decodings

From RF to composite video
From composite video to S-video
From S-video to YIQ or YUV component video
From YIQ or YUV to RGB

* NTSC, PAL, and SECAM each has its own version of composite video.

** Some studio equipment encodes directly from RGB to YIQ, some TV sets decode directly from YIQ to RGB. YIQ has two color signals representing orange/blue and green/purple respectively. YUV has two color signals where the accompanying luminance signal is used to derive the red and blue first and then the three are used to derive the green signal. YUV and YIQ represent colors equally well within the allotted bandwidth for the color signals.

The fewer encodings and decodings, the better. More encoding means more electronics in the signal path and there is some loss of quality. The most difficult and least perfect decoding is from composite video to S-video, which at best is done using a comb filter. By careful selection of the cabling connections you can minimize the amount of encoding and decoding limited only by the capabilities of your equipment.

In order to be broadcast as a TV show, the RGB signals coming from the TV camera have to be encoded using all of the methods above to fit in a TV channel. Normally program sources in the home or business do not require all of that encoding. But if the TV set used for viewing has nothing other than an antenna input, the VCR, DVD player, etc. must encode the signal as a TV channel in order to feed into the TV, using its built in circuitry specially provided for just that purpose.

Laser disks are recorded using a composite video signal. Therefore the unaltered signal from the playback is composite. S-video from an LD player is more a gimmick than anything else. The only reason to buy an LD player with S-video is to get a comb filter that is better than that in your TV set, which quality is not easy to verify.

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Recording Programs Using Your A/V Receiver

With your VCR connected to the A/V receiver via the composite jacks, you can easily record from any of the composite video program sources. If your S-video (or component video) direct feed receiver has enough jacks, you can connect a DVD player using both an S-video (or component video) cable and a composite video cable. The ultimate capability is being able to select your program source and get audio, S-video, and matching composite video in tandem. The S-video signal is passed directly to the TV while the composite signal enters the receiver at a point where the VCR can pick it up. Use S-video instead of composite video if the VCR accepts that for input.

Connecting many program sources: DVD, LD, VHS, Web TV

A summary, my opinion only. Use these guidelines for connecting equipment directly to a TV set.

Connecting Your DVD Player:

First choice is digital (e.g. DVI) at 720 x 480 or greater
Second choice is component video (Y/Pb/Pr), or RGB
Third choice is DVI at 640 x 480
Fourth choice is S-video (Y/C)
Distant fifth choice is composite video (yellow video jack)

The video signal from playing back a DVD is put into the component video format first. S-video is constructed using the component video, and composite video is constructed using the S-video. So component video not only has the best quality but is also the simplest DVD player output. (Some DVD players output S-video and composite only.)

Connecting Your Laser Disk Player:

First choice is regular (composite) video out but also see Part 2 below.
Second choice is S-video, but also see Part 2 below.
Channel 3/4 (RF or antenna coax) is a distant third.

Laser disks are recorded with a composite video signal so, unlike DVD, the easiest output the LD player can produce is composite. The only way an LD player can output S-video is if it contains its own comb filter (or a cheap substitute) to separate the luminance and color portions.

If there is an S-video or component video output jack, try both it and the regular video out jack one at a time plugged directly into the back of the TV. Use whatever cable combination gives the best picture.

What this testing does is figure out which device has the best comb filter. With an S-video cable the LD player uses its own comb filter, and with the composite cable it takes advantage of the TV set's comb filter.

Connecting Laser Disk Player -- Part 2 (9/98)

We have learned that a small number of high end LD players and S-VHS VCR's deliver degraded video signal from their composite output. This is because the signal from the disk is put through the player's own comb filter and then recombined (recomposited) for output via the composite jack. This is very unfortunate because the TV set comb filter is still called into play and if you choose a composite connection, the signal ends up going through two comb filters. On some player models there is no way to bypass the player's comb filter even if the comb filter in your TV set is better.

If your TV set has an S-video jack, fortunately the same rule applies, try both composite and S-video connections to see what gives the better picture. In the case of an S-VHS VCR, try this test with broadcast programs.

We believe that forced use of the LD player's comb filter is highly disadvantageous. As far as we can tell, only a few models of players with "digital time base correction" have this problem. We don't know what models they are. We can only hope that the LD player's comb filter is so good the S-video viewers have no complaints and composite video viewers can't notice the added degradation.

Reference: Bob Niland, laser disk article #92 subject to availability.

Connecting Combination LD/DVD Player

Like the straight LD player, the combination LD/DVD player may or may not deliver better LD video from its S-video jack depending on the quality of the built in comb filter. Meanwhile the first choice for DVD is still component and the second choice is still S-video. Also some LD/DVD players don't deliver anything from their component jacks when an LD is being played. Most likely you will have to run two cable sets from the player to the TV.

Connecting a VCR or Camcorder:

For playing tapes:
First choice is S-video (if jacks are present) **
Second choice is composite video
Third choice is channel 3/4 (RF)
For viewing broadcasts via the VCR's tuner**:
Tie for composite video or RF
S-video is a distant third (unless VCR has built in comb filter).

The video signal is recorded on all common videocassettes in a format similar to S-video. In other words the easiest output for a VCR to produce when playing tapes is S-video. However the color resolution is at best 40 lines for all colors including for Super VHS and High-8. Luminance resolution is still only 240 lines for non-super VHS or non-High-8. Unfortunately few non-S-VHS VCR's offer S-video output. Instead the signal is almost always made available to you in a choice of composite video or RF. A major part of the quality loss as videocassettes are duplicated at home is the encoding to composite video for output via the video out jack of one VCR and the internal decoding back to S-video for recording the tape copy.

** S-video from a VCR gives the best tape playback but not always the best live reception. Use the TV's tuner to get better broadcast reception. A non-super VHS VCR uses a notch filter (usually instead of a comb filter) to translate RF into S-video and in so doing limits horizontal resolution to about 240 lines (which is enough for the tape).

Web TV:

I am not familiar with this one but if it has a component video or S-video output, I would compare the picture quality with using the regular video out jack. However I would connect the preceding units first and give Web TV whatever jack was left over.

Connecting Ordinary Cable TV Box

Most cable TV tuner boxes have just one output, which plays into channel 3 or 4 of your TV. If this is the case, connect the cable box either to the antenna in terminal or jack of your TV or the antenna in terminal or jack of your VCR.

Digital Cable, Digital Satellite (DSS), HDTV

To actually see an HDTV program in high definition you must use component video (or RGB). Otherwise you would use component video or S-video. A complication arises when the same tuner box also receives analog channels, either provided on the cable or from an antenna. For the analog channels try both the composite output and the S-video output. A cable box needs a comb filter to deliver analog channels via S-video and the comb filter may or may not be better than that in your TV set. It may be desirable to run both S-video and composite video cables from the cable box to the TV or A/V receiver

Use switch boxes rather than Y-connectors, click here for more details.

Boosters and Splitters (8/98)

If you are feeding several TV sets from one antenna using a booster (amplifier) and several splitters, connect all of the output legs of the splitters to other splitters, not to the first TV set. You want to construct a more or less symmetric tree of splitters so that the path to each TV set goes through almost the same number of splitters. This prevents overloading the first TV set causing ghosts in the picture.

If one of your splitters has more than two output legs, connect it to the booster output.

If a splitter output jack is labeled "Use this first", connect the continuing cable (subtree) serving the path(s) with a greater number of additional splitters to it.

(A change from earlier advice) There is no rule as to where to mount the splitters although you may have to run extra cable or double back cable here and there to arrange the splitters in a symmetric tree. (Cable lengths do not have to be equal.) The splitters do not have to be next to each other.

Do not buy splitters with more legs than you need. The reception will be weaker even with nothing connected to the unused legs..

Do not use Y-connectors or fabricate your own connections instead of using splitters. The various TV sets will emit spurious signals that can interfere with each other while the splitter blocks these spurious signals.

An antenna booster that has several (more than six) output jacks is called an RF distribution amplifier. I would expect but cannot be sure that, given the same number of dB gain, the RF distribution amplifier will deliver a stronger signal to each of its outputs compared with an ordinary booster connected to a tree of splitters.

A splitter, including that built into a distribution amplifier, is typically a few coils of wire wrapped around an iron or ferrite core, somewhat like several people standing together holding a broomstick or a pole inside a subway train. It is possible to have reception problems with some but not all TV channels and for the quality of reception to vary among the outputs of a given splitter. Each TV channel is a different band of frequencies and a splitter is not guaranteed to treat them equally. A splitter is not perfect; the sum of the output signals strengthwise is always less than the input signal.

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