How to choose a VCR

The most important specifications

• Tape format. VHS is by far the most common video format in use today and the automatic choice for most users. An S-VHS machine will play and record in standard VHS, but can also use "Super VHS" tapes to produce higher resolution and reduce loss of detail in dubbing down 2 or 3 generations, a problem when creating your own video productions. (S-VHS improves picture quality by keeping the chrominance, or color component of the video signal, separate from the luminance, or detail segment, thus eliminating noise created by their interaction.) Video 8 (or 8mm) offers picture quality identical to VHS but with CD quality audio and in a much smaller cassette (and thus much smaller equipment); Hi-8 is the 8mm equivalent to S-VHS. U-matic, or 3/4," uses a wider tape as means to increase production quality. There are several other formats used strictly for video including U-matic SP Betacam and 1 plus new digital formats. in addition many Panasonic VHS decks feature quasi playback which they will play an S-VHS though only at standard resolution. (They not record S-VHS).>

• Television signal format. All of these tape formats are available in NTSC, the American signal standard, plus PAL, SECAM, N-PAL, M-PAL and MESECAM, which are used in various parts of the world. Most VCRs sold in this country only record and play in the NTSC format and that is sufficient for nearly all consumers. However, if, in your occupation, you need the ability to play tapes made in other countries on a regular basis you will need a multi-standard VCR. Because of the complexity in converting a recorded signal from another country to NTSC you can expect to pay a premium for these units. Oddly, it is less difficult to design a monitor or projector capable of displaying multiple signal standards so they are more abundant and competitively priced.

• Audio quality. VHS Hi-Fi audio is a recording format where stereo audio signals are recorded using high speed rotary audio heads similar to the way video is recorded. Standard VHS linear audio tracks are recorded with stationary heads as the slow moving video tape goes by. In general, the faster the tape moves past the recording heads, the better the sound reproduction. In fact, Hi-Fi audio recording produces sound quality close to audio CDs and, well into the specification ranges used for professional audio recording equipment. Hi-Fi decks also record and play the audio tracks normally recorded by a standard VCR. Both 8mm formats offer the same CD quality audio as VHS Hi-Fi, the difference being Video 8 records in monaural, while Hi-8 records in stereo.

• The number of heads can make a difference picture quality in record and playback. A four-head machine has two additional thicker heads for standard play (SP) recording and playback. Thus you get a much better SP quality than on 2 head machines which use thinner heads for all speeds. If a machine has only 3 heads, or more than 4 heads, the additional head(s) are used only for special effects. Therefore, you get a much cleaner slow motion and still picture, but no increase in picture quality in record or playback.

• Resolution measure the amount of detail that can be seen in a video image, expressed as the number of lines visible on a test pattern. Resolution is thus a good overall indication of the quality of the image you'll get on your tape. Your VCR's format is often the limiting factor in the resolution of your video system, with VHS producing about 220-260 lines, VHS-HQ 300 lines, and S-VHS 400-440 lines. If detail is critical for your application, S-VHS or Hi-8 is worth considering.

• Signal to noise ratio measures the most intense video or audio signal your VCR can reproduce versus its background noise level. A ratio of 58dB, for example, means there can be up to 58dBs of signal for every 1dB of noise. Higher ratios thus mean a cleaner signal.

• Audio frequency response measures the range of tones that your equipment is able to reproduce. Most people are able to hear tones as low as 30Hz and as high as 15,000Hz, though many can hear as high as 20,000Hz. If you are buying your equipment to play back prerecorded videos or will be taping programming off the air, you will find a wider range makes a noticeable difference in the quality of what you hear.

Useful features

• Auto-repeat is useful for automated presentations, such as those in a trade show, kiosk, or other public display. End of tape repeat means that the unit will play the entire videotape, rewind and begin playing again. End of program repeat means that the VCR senses the point on the cassette where no signal has been recorded and at that point rewinds and begins playing again. Programmable repeat allows you to specify any beginning and ending point.

• Timer play or power-on playback allows you to start an automated presentation at the times you set on a timer.

• Sequential playback eliminates the need to stop an automated presentation while the tape rewinds. If you have two units with this feature, you can program one to begin playing when the other stops, then the first one to play again when the second one stops (and so on).

• Various search features can be very useful in a VCR. Index search allows you to fast forward or rewind to any point where the VCR began recording (say at the start of taping with your camcorder, or at the start of a TV program). Zero search allows you to move to any point on the tape where you have zeroed the counter, and memory search to any memory point you have set. Program search allows you to fast forward or rewind to any point you specify.

• A jog/shuttle dial allows you to quickly change the search speed of the deck in many increments, from still frame, to variable slow motion, to high speed forward or rewind. In multiple head VCRs which are capable of clear slow motion, the jog/shuttle dial makes motion analyzing easy, an important feature for athletic coaches and others who use video to analyze events. If you have such a need, contact us for information on specialty remote controls from Webb Electronics.

• Audio dub capability allows you to record audio without disturbing video that is already on the tape–for example, to add narration or music. Audio dub cannot be used to replace audio on VHS Hi-Fi machines because of the way the audio track is recorded, however an additional audio track, such as background music, can be added with audio dub on this type of machine.

• Independent audio tracks allow you to record on two or more tracks separately.

• Slow motion playback is of particular importance to coaches and others who use video to analyze events. If you have such a need, be sure to look at the remote controls from Webb Electronics on page 61.

Beyond the specifications

• Reliability is a critical factor in VCR selection, since a VCR has more moving parts than any other piece of equipment you're likely to own, aside from your car. The complexity of these units makes repair difficult, and if you use your machine frequently, it's easy to add up repair bills two or three times your "savings" in buying an off brand. So it's particularly important to ask about the manufacturer's reputation for reliability, the length of the warranty, and your dealer's policy on repair costs and turnaround.

How to choose a laserdisc player
Most of the suggestions here apply to laserdisc players as well as VCRs: resolution, signal to noise ratio, and reliability are critical to your choice of a new player. But there are several additional considerations to keep in mind. Among them:

• Compatibility. Most packaged interactive software is written to run on Pioneer players and barcode readers. If you plan to use such software and you prefer another brand of player, be sure it's 100% compatible with your software.

• Disc format. There are two videodisc formats in common use today. CAV is most often used for interactive programs. CLV, with its extended playback time (but limited interactivity) is most often used for movies. Most users don't need to worry about the advantages of one format over another, but they do need to be sure their new player will play the software they will use.

• Search speed. Most current players will find any frame on the videodisc in about two seconds; higher-speed machines can search in 1/2 to one second. You'll probably want a machine like this only if you are designing a system for a video kiosk or museum display–applications where segment changes are frequent and audiences are likely to walk away if there's any break in the action