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How to choose a VCR
The most important specifications
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).>
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
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.
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.
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.
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.
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.
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.
play or power-on playback allows you to start an automated
presentation at the times you set on a timer.
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).
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.
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.
dub capability allows you to record audio without disturbing
video that is already on the tapefor 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.
audio tracks allow you to record on two or more tracks separately.
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.
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.
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:
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.
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.
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
displayapplications where segment changes are frequent
and audiences are likely to walk away if there's any break
in the action