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1991-11-02
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EXCHANGING VHS CASSETTES WITH FOREIGN VIEWERS AND
USING VHS RECORDERS ABROAD
INTRODUCTION
Exchanging any video program with someone living abroad is complicated by
the fact that most of the world does not use the American TV system.
Regardless of the tape format used (i.e., VHS, SVHS, Beta, 8 mm, etc.)
foreign video recordings cannot be played on an incompatible player, or
displayed on an incompatible TV receiver.
I will try to describe here some "tips and traps" of exchanging video
recordings with foreign viewers and on using your NTSC camcoder in foreign
countries. Since the VHS home recording system predominates at-present, I
will describe here only the specific problems that relate to VHS.
Since the SVHS format differs only in the way in which the luminance
information is separated and recorded, all of the information below applies
equally to SVHS. The details regarding the TV standards themselves are
applicable to all recording formats.
THE WORLD'S TV STANDARDS
The color television system in use in the United States was adopted in
1953, and because the United States was the first to widely implement color
television, we have the oldest (though not necessarily the best) color
television standard in the world. Considering the era in which it was
devised, the system represents nothing short of genius on the part of its
designers. Our TV system acted as the progenitor of all of the other TV
broadcast systems to come.
Our TV system is referred to as "NTSC" (National Television System
Committee), and is used only in the U.S., Canada, Mexico, Central America,
the UAE, Burma, the Pacific coastal countries in South America, and in
parts of the Far East. When implemented, it represented a comprised effort
to transmit color video within a comparatively narrow bandwidth allocation,
while it maintained compatibility with the 100,000 or so black-and-white
televisions that had already been sold in the U.S.
The European countries began broadcasting color television in the late 50's
and early 60's, and having had the dual advantages of time to improve on
our system, and wider channel bandwidth assignments; adopted either the PAL
(Phase Alternating Line) or SECAM (the French acronym for Sequential Color
with Memory) color TV systems. Both the PAL and SECAM systems were
intended to alleviated some inherent weaknesses in the early vacuum tube
based NTSC equipment, although today their greatest advantage over NTSC
stems from their wider bandwidth allocations. With the narrower channel
bandwidths used in the U.S., it would be impossible for us to "switch" to
either the European PAL or SECAM systems.
Besides PAL and SECAM, there also exist two additional color TV standards:
PAL-M, which is used only in Brazil; and PAL-N, which is used in Argentina,
Paraguay, and Uruguay. PAL-M is a "hybrid" of both the NTSC and European
PAL systems. It is an attempt to "fit" the PAL system within the same
frequency spectrum that is used by NTSC. PAL-M uses the same
specifications as NTSC for the black-and-white portion of the program
(referred to in TV parlance as the "luminance" information), but it uses a
modified form of the PAL system for its color (or "chrominance")
information. Thus, NTSC and Brazilian PAL-M VHS recordings are
interchangeable -- but only for black-and-white playback. While some PAL-M
VHS machines are capable of playing NTSC, PAL-M televisions cannot
reproduce the color portion of an NTSC program without using a special
device known as a "transcoder." A transcoder takes the video program and
reduces it to its color components - much like a television receiver does -
and then reassembles these components in the new TV standard. Transcoding
is a far simpler process than standards conversion, but it can only be used
when the black-and-white standards of the two TV systems are the same.
PAL-N on the other hand, uses the same black-and-white system as PAL and
SECAM, but with a slightly modified PAL system for conveying the color
information within a narrower RF bandwidth. PAL-N can be transcoded to or
from either PAL or SECAM.
TV STANDARDS CONVERSION
The process of TV standards conversion involves accurately converting video
information to a receiving rate that is different than the rate at which it
is being transmitted. In NTSC, 30 (actually 29.97) "frames," or individual
pictures, are transmitted each second. These frames are very similar from
a conceptual standpoint to the individual frames in a motion picture. Also
in NTSC, each frame is made up of 525 individual scan lines. PAL on the
other hand has only 25 frames per second (5 fewer per second than NTSC),
and has 625 lines per frame (100 more than NTSC).
The world today has fortunately settled on only two line and frame
rate standards:
NTSC & PAL-M use 30 frames per second and 525 lines per frame.
PAL, PAL-N, & SECAM use 25 frames per second and 625 lines per frame.
A standards conversion from NTSC to PAL involves discarding 5 frames per
second, while literally inventing 100 lines per frame. If the extra frames
were simply thrown away, the resulting video would be so full of jerks and
jumps that it would be unviewable, so a good standards converter will
"interpolate" or average the information from one frame to the next. The
standards converter does this by storing one or more frames in an
electronic memory and then performing a comparison between the stored
frames. The more memory -- the more accurate is this averaging process.
The extra lines are either invented or discarded by a similar averaging
system. The inner workings of modern TV standards converters are actually
much more complex than described above: a modern converter uses high speed
real-time computing techniques to detect and differentiate between moving
and stationary objects in every frame of every scene in order to further
reduce the appearance of jerkiness in the converted video.
TV STANDARDS IN USE
The following is a list of TV broadcast standards in use. This information
is based on the XVIth Plenary Assembly of the Consultative Committee
International Radio (CCIR), Dubrovnik, 1986.
NTSC COUNTRIES:
Bermudas
Bolivia
British Virgin Islands
Burma
Canada
Chile
Colombia
Costa Rica
Cuba
Dominican Republic
Ecuador
Guatemala
Haiti
Honduras
Jamaica
Japan
Korea (South)
Mexico
Montserrat
Netherland Antilles
Nicaragua
Panama
Peru
Philippines
Saint Christ. and Nevis
Surinam
United Arab Emirates
United States
Venezuela
PAL COUNTRIES:
*PAL-N Standard **PAL-M Standard
Albania
Algeria
Angola
Argentina*
Australia
Bahrain
Bangladesh
Belgium
Botswana
Brazil**
Brunei
Cameroon
China (People's Republic)
Denmark,
with Greenland and Faroes
Equatorial Guinea
Ethiopia
Finland
Germany (Unified) (SECAM is currently being
simulcast in what was formerly "East"
Germany)
Ghana
Gibraltar
Great Britain (England, Scotland, & Wales)
Hong kong
Iceland
India
Indonesia
Ireland (Northern & Rep. of)
Israel
Italy
Jordan
Kenya
Korea (North)
Kuwait
Lesotho
Liberia
Luxembourg
Malawi
Malaysia
Maldives
Malta
Monaco
Mozambique
Netherlands
New Guinea
New Zealand
Nigeria
Norway
Oman
Pakistan
Paraguay*
Portugal
Qatar
Romania
Sierra Leone
Singapore
South Africa
Spain
Sri Lanka
Sudan
Sweden
Switzerland
Syria
Tanzania
Thailand
Tunisia
Turkey
Uganda
Uruguay*
Yemen (North & South)
Yugoslavia
Zambia
Zimbabwe
SECAM COUNTRIES:
(Note: Except for France, either the MESECAM or PAL systems are the
preferred standards for VHS interchange - refer to text below)
Afghanistan
Benin
Bulgaria
Burkina Faso
Burundi
Central African Rep.
Chad
Congo
Cyprus
Czechoslovakia
Djibouti
Egypt
France
Gabon
Greece
Guinea
Hungary
Iran
Iraq
Ivory Coast
Lebanon
Libya
Madagascar
Mali
Mauritania
Mongolia
Morocco
Niger
Poland
Rwanda
Saudi Arabia
Senegal
Togo
USSR
Vietnam
Zaire
Occasionally you may encounter suffix letters after the TV standard
specification, i.e., "PAL-B, PAL-I, SECAM D/K", etc. These suffixes refer
to internationally agreed upon TRANSMISSION standards (promulgated by the
CCIR), and are important only for TV receivers/tuners and transmitters/RF
converters. Except for the two unusual standards of PAL-M and PAL-N, which
are separate TV systems in their own right, these terms are irrelevant for
the exchange of PRERECORDED VHS cassettes.
Finally, there are two methods of recording SECAM on VHS. The first method
complies with the accepted JVC "standard" for SECAM recording and is
generally referred to as either the "Standard" or "French" SECAM method.
(Because of the prevalence of Standard SECAM machines in France, the
Standard SECAM recording method is often referred to as "French SECAM.")
The second, and most common method, is referred to as "MESECAM," or Middle
East SECAM. The "Middle East SECAM" method derives its name from the fact
that the Middle East has a checkerboard of PAL and SECAM broadcast
services. MESECAM was developed to allow a PAL VHS machine to record both
PAL and SECAM broadcasts with only a very slight modification of the PAL
circuitry. Unfortunately, not only is MESECAM video quality inferior to
"Standard" SECAM VHS, but the method of recording SECAM video on the tape
itself makes the recording incompatible with a "Standard" or "French" SECAM
VHS machine -- SECAM recordings that are interchanged between MESECAM and
Standard SECAM VHS machines will play back in black-and-white only. (For
those who are interested in the technical reason for this incompatibility:
MESECAM uses a heterodyne method for deriving the color-under subcarrier --
the same method that is used for PAL and NTSC VHS, whereas Standard SECAM
digitally divides the two SECAM FM chrominance subcarriers by 4. If the
wrong reverse-process is used on playback, it results in the SECAM
subcarriers being at the wrong frequencies, and the sidebands being too
wide or too narrow.)
With the exception of France, MESECAM is by far the most common VHS system
used in SECAM broadcast countries. This is partly a matter of
supply/demand economics, and partly because many of the countries that are
broadcasting SECAM have had closed socialist economies in the past. As a
result of these closed systems, most of the video software that has been
obtainable has had to be smuggled in from the West -- and was recorded in
PAL. Everyone who has a MESECAM VHS machine also has the ability to play
PAL recordings, and with the addition of a simple transcoder, a SECAM TV
receiver can display PAL recordings in color. If the intended recipient of
a VHS cassette has the ability to play PAL recordings I suggest that you
send recordings in PAL rather than MESECAM due to the differences in
recording quality.
BLANK VHS CASSETTES
As described above, there are 5 color television standards in use
throughout the world, and 6 ways of recording video on VHS. Without
"standards conversion," the only foreign standard that can be played at all
on an American VHS machine is PAL-M (the Brazilian standard), and then only
in black-and-white.
Fortunately, the situation is far less complicated with regard to BLANK VHS
cassettes. VHS cassettes are mechanically identical in all TV standards.
The only difference is that the tape SPEED is higher in NTSC (and PAL-M),
and therefore, the recording time in NTSC is shorter for a given amount of
tape.
NTSC consumes tape at a rate of 2.0 meters per minute in standard play (SP)
mode, and both PAL and SECAM consume tape at a rate of 1.42 meters per
minute. Although it isn't necessary to take blank VHS cassettes along with
you on a trip to Europe, you will need to do a little math to determine the
recording time allowed on a blank European VHS cassette. The tape
manufacturers generally make this easier for you by showing both the length
(in meters) of the blank tape, and by designating the labelled European or
American length with a code letter. American (NTSC) blank cassettes are
marked with the letter "T" preceding the length, e.g., T-120; and European
PAL/SECAM cassettes are marked with the letter "E" before the length, e.g.,
E-180.
An E-180 (180 minutes in PAL/SECAM) cassette will contain approximately 258
meters of blank tape, and on this blank tape you can record: 258 divided by
2 minutes of NTSC video; or 129 minutes of NTSC program.
The following is a conversion table of tape lengths and recording times:
Length code Blank tape length * NTSC/PAL-M time PAL/PAL-N/SECAM time
----------- ----------------- --------------- --------------------
T-20 44 meters 20 minutes 28 minutes
T-30 64 meters 30 minutes 42 minutes
T-40 84 meters 40 minutes 56 minutes
T-45 94 meters 45 minutes 63 minutes
T-60 125 meters 60 minutes 84 minutes
T-80 165 meters 80 minutes 112 minutes
T-90 185 meters 90 minutes 126 minutes
T-120 246 meters 120 minutes 169 minutes
T-130 266 meters 130 minutes 183 minutes
T-160 326 meters 160 Minutes 225 minutes
E-30 45 meters 22 minutes 30 minutes
E-60 88 meters 44 minutes 60 minutes
E-90 130 meters 65 minutes 90 minutes
E-120 173 meters 86 minutes 120 minutes
E-150 215 meters 107 minutes 150 minutes
E-180 258 meters 129 minutes 180 minutes
E-240 346 meters 173 minutes 240 minutes
* Most tape manufactures add 3 to 6 meters of blank tape to their cassettes
to allow for tape threading in the mechanism and for recording speed
inaccuracies.
EXCHANGING VHS RECORDINGS BETWEEN TV STANDARDS:
There are only four possible methods of viewing a VHS recording in a
foreign TV standard:
1) purchase a multistandard converting VCR (such as the Panasonic AG-W1),
2) purchase a VCR and television (and usually a voltage conversion
transformer) designed for the foreign standard,
3) "transcode" the video to the viewer's TV standard or,
4) have the tape standards converted to the viewer's "home" television
standard.
If the exchange is between NTSC and PAL or SECAM countries, the first two
options will involve an expense of around $2,000. The third option,
transcoding, is inexpensive and quite popular in Eastern Europe where
there are very few pre-recorded movies available in SECAM. (In fact, in a
recent survey of Leningrad, USSR - a SECAM country - I was unable to find
any SECAM recordings at the video rental shops - all of their recordings
were in PAL. The Soviet Union now manufactures color televisions that
eliminate the need for a transcoder by automatically detecting and
transcoding PAL programs, such as the "Raduga" or "Rainbow" TV receiver
manufactured by Elektornika in Leningrad.) Unfortunately, the transcoding
method can only be used when converting video between two TV standards that
have the same line and frame rate standards (the same black-and-white
system). Transcoding is not an option when converting between PAL or SECAM
and NTSC. The fourth option, standards conversion, is an economically
appropriate method for an occasional exchange of video programs between
NTSC and PAL/SECAM countries. Standards conversion of a VHS cassette will
cost approximately $20 per hour of program, and this service can be
provided usually with a 4 or 5 day turn-around to any location in the U.S.
by firms such as Video Bridge (telephone: 800-877-4015).
When having a VHS cassette standards converted, it is important to make
sure that a digital process is being used for the conversion. The results
of the older analog standards converters are inferior in all respects, and
most laboratories today use digital "8 bit/2 field" - and more recently -
"8 bit/4 field" systems. The biggest difference between the 2 field and 4
field systems is in the accuracy of their motion interpolation. With the
older 2 field systems, moving objects in the video, particularly background
scenes during a camera pan, will occasionally appear to jump from point-to-
point rather than moving smoothly. Although the video output from a 4
field converter still represents something of a compromise, moving objects
appear much more natural. (Since the typical cost of an 8 bit/4 field
converter is $90,000, some laboratories have yet to upgrade their
equipment.) The most rudimentary method of standards conversion involves
literally pointing a TV camera of one standard at a TV display of another
standard. This method produces results that are absolutely unacceptable to
most viewers today.
If you are sending a converted VHS cassette to Europe, it is also important
to determine if the conversion service is recording audio using the Hi-Fi
(sometimes called "HD") FM recording system. Hi-Fi audio capability is far
more common in Europe than in the U.S., and some conversion services here
in the U.S. try to skimp on this point.
TV standards conversion today costs only a fraction of what it cost just a
few years ago, and with the power of real-time computing performing motion
detection, time-base correction, interpolation, noise reduction and image
enhancement; the quality of converted video has improved to the point that
the conversion process has not only become essentially transparent, but
often the converted copies are superior to the original. In fact, most of
the international programming that we see today was converted using the
same technology that will be applied to your videos. If you intend to
exchange video programs with someone living abroad, you can do so today by
using any of the quality standards conversion services.
The following glossary of terms is intended to assist you
with the specialized terminology used in international
television standards.
Glossary: Glossary:
Legend: The following designations have been used to avoid
confusion, and to separate the definitions of terms
that have multiple meanings:
(Video): Applies to a video standard.
(VHS): Applies to the method of recording or
reproducing video with a VHS machine.
(RF): Applies to radio frequency spectrum
allocations, usually embodied in
international treaties. Used to
describe the design of television
transmitters, receivers, and tuners.
(Receivers): Applies to terms used to describe the
design of television receivers.
CCIR (Video) The French acronym for International Radio
Consultative Committee. The CCIR has
established recommendations for the video and
transmission characteristics of all of the
world's television systems. The term "CCIR
video" is often encountered and is
meaningless unless the television video
standard to which this term applies is
further specified. As a colloquialism, the
term "CCIR video" is most frequently
used in reference to the monochrome
standards of 625 lines per frame and 50
fields per second; as well as the voltages,
aspect ratios, gammas, etc., that both PAL
and SECAM have in common. Since both PAL
and SECAM are the same monochrome video
standard, what is usually meant by this
colloquial usage is simply; "black-and-white
PAL/SECAM." "CCIR video" is often touted by
VHS manufacturers as if it were a separate
video or VHS standard. The term "CCIR video"
has been used erroneously by at least one VHS
manufacturer in reference to MESECAM (VHS).
EIA (Video) Electronic Industries Association. Often
used to refer to the original monochrome
standard from which NTSC was later
developed, i.e., 525 lines per frame and 60
fields per second. The term "EIA video" is
sometimes used to refer to "NTSC without
color information." "EIA video" is often
touted by VHS manufacturers a separate video
standard, when in fact it is merely black-
and-white NTSC.
THE NTSC SYSTEMS:
EIA 4.43 MHz A colloquial misnomer. See N443 (Video/VHS).
(Video/VHS)
N443, or An unofficial television video standard.
NTSC 4.43 With NTSC 4.43 (or N443), a recording is made
(Video/VHS) in normal NTSC. The recorded tape may then
be viewed on a compatible PAL monitor that is
capable of "locking" its deflection circuitry
onto the NTSC line and field rates. During
playback, the down-converted chrominance
sidebands that are centered around 629 kHz
on the tape, are up-converted to be centered
around 4.43 MHz. Since the video was recorded
with the NTSC color system, a compatible PAL
monitor will detect a 59.94 Hz field rate
(NTSC) and will disable its PAL "switching"
circuitry and thus reproduce color NTSC
pictures (but without the advantages of the
PAL color "system," i.e., the phase of the R-
Y component will not be reversed on alternate
lines). This allows the playing of NTSC tapes
in PAL countries on compatible tape machines,
without the use of an expensive standards
converter. Unfortunately, comparatively few
multistandard VHS machines and monitors
exist. Therefore, this "standard" is of
little significance for exchanging VHS programs.
NTSC 3.58 Ordinary NTSC color video. This term is used
(Video/VHS) on some multistandard VHS machines and
receivers/monitors to distinguish normal NTSC
from the NTSC 4.43 "standard."
NTSC National Television System Committee. The
(Video/VHS) color television video standard used
throughout North America, in much of
Central and South America, and in much of
East Asia. Implemented in 1953, it was the
first form of monochrome-compatible color
television, and uses a slightly modified
version of the original 525 lines per
frame/60 fields per second monochrome system.
NTSC employs suppressed-carrier
quadrature amplitude modulation for
transmitting two color difference signals
(I and Q) on a 3.58 MHz suppressed
subcarrier. There is no interchangeability
of recorded material between non-
multistandard PAL-N/PAL/SECAM (625 line/50
field) and NTSC/PAL-M (525 line/60 field) VHS
machines. NTSC may be transcoded to PAL-M.
SuperNTSC * A proprietary NTSC-compatible "line doubling"
(Receivers/ technique developed by Faroudja Laboratories
Video) that provides enhanced definition video.
Although full implementation of the system
requires a decoder and line-doubler at the
receiver end, receivers without decoders are
claimed to benefit from the removal of NTSC
"artifacts."
M/NTSC (RF) Also called NTSC-M. The "M" designation is
of no interest in VHS duplication. M/NTSC is
the transmission/video standard that is used
in the United States and in all other NTSC
countries except Jamaica.
THE PAL SYSTEMS:
PAL Phase Alternating Line. An improvement of
(Video/VHS) NTSC video. Since PAL was implemented
mostly in countries using 50 hertz mains
supply power and the early scanners (Nipkow
disc, Weiller wheel, and film scanners) made
use of AC supplied synchronous motors, a
field frequency of 50 fields per second was
chosen. PAL uses 625 lines per frame. In
the PAL video standard, the phase of the R-Y
(or "V") component is reversed on alternate
lines, and thus any phase distortion that
occurs in transmission can be "averaged out"
at the receiver by use of a delay line.
Unlike NTSC, in the PAL system differential
phase errors do not appear as objectionable
hue errors in the displayed video (the colors
become desaturated instead). The PAL system
does not eliminate the distortions in color
saturation that are caused by either
differential gain errors or as a by-product
of differential phase errors. Like NTSC, PAL
employs a similar method of suppressed-
carrier quadrature amplitude modulation for
transmitting two color difference signals
(designated "U" and "V"); but on a subcarrier
frequency of 4.43 MHz. There is no
interchangeability of recorded material
between non-multistandard PAL and NTSC VHS
machines. PAL VHS recordings are
interchangeable with SECAM (VHS) and MESECAM
(VHS), but only for monochrome playback. PAL
can be transcoded to SECAM and PAL-N.
PAL B Refers to the modern form of the PAL video
standard. This term is rarely encountered.
This term should not be confused with PAL
video that is transmitted within the
bandwidth limits and on the channel spacings
that carry a CCIR "B" designation {see also
B/PAL (RF)}.
PAL D PAL Deluxe. Referred to occasionally as
(Receivers) "D.L. PAL." This is a receiver/monitor
specification, and the term has no
application to VHS or to the PAL video
standard. In PAL D, a delay line is used in
the receiver or monitor to average the
chrominance on alternating lines. Many
studio monitors allow this delay line to be
switched off, yielding "simple PAL." Due to
the averaging of the chrominance information,
use of a delay line results in an inherent
reduction in vertical chrominance resolution,
but alleviates an effect in PAL known as
"Hanover bars," which occur in the presence
of moderate differential phase distortion.
This term should not be confused with PAL
video that is transmitted within the
bandwidth limits and on the channel spacings
that carry a CCIR "D" designation {see also
D/PAL (RF)}.
Simple PAL See PAL D (Receivers).
(Receivers)
PAL-M A television video standard used only
(Video/VHS/RF) in Brazil. PAL-M uses the same 525 line 60
field system as NTSC for monochrome video
(RF bandwidth, field/line rates, gamma,
etc.), but it uses the PAL system (with a
modified subcarrier frequency) for its color
information. Since PAL-M has the same line
and field rates as NTSC, PAL-M can be
transcoded to and from NTSC.
PAL-N A television video standard used principally
(Video/RF) in Argentina. PAL-N uses the same color
system and line/field rates as PAL, but with
a lower subcarrier frequency to accommodate
restricted RF bandwidth allocations for
broadcasting. Most PAL-N VHS machines are capable
of playing (standard) PAL recordings. PAL-N
can be transcoded to PAL and SECAM.
B/PAL (RF) A transmission standard that specifies
channel spacings and bandwidths for
transmitters and tuners. Does not relate
directly to VHS recordings. The "B"
designation is of no interest in VHS
duplication. B/PAL channel assignments are
used by the majority of PAL countries, with
the notable exception of the United Kingdom.
D,G,H,/PAL A transmission standard that specifies
(RF) channel spacings and bandwidths for
transmitters and tuners. Does not relate
directly to VHS recordings. The "D,G,or H"
designation is of no interest in VHS
duplication. The CCIR designation "D/PAL"
should not be confused with the PAL D receiver
specification {see also PAL D (Receivers)}.
I/PAL (RF) A transmission standard that specifies
channel spacings and bandwidths for
transmitters and tuners. Does not relate
directly to VHS recordings. The "I"
designation is of no interest in VHS
duplication.
THE SECAM SYSTEMS:
SECAM (Video) Sequence Couleur a Memoire, or Sequential
Color with Memory. A monochrome-compatible
color television video standard proposed in
1959/1960, and intended to reduce the
problems of crosstalk between the two color
difference signals and the problems of
differential gain that are inherent in both
the PAL and NTSC video standards. SECAM
circumvents these problems by using two FM
carriers to convey the color information.
SECAM uses the same set of specifications as
PAL for its luminance information, and is
therefore the same monochrome video standard
as PAL. SECAM differs from PAL only in the
way that its chrominance information is
conveyed. The CCIR recommends a single
standard for SECAM video, and only slight and
generally irrelevant dissimilarities exist in
SECAM video in the countries in which it is
used; the most notable difference being the
deletion of vertical-interval "bottles" in
some countries {see SECAM Bottles (Video)}.
There are two incompatible methods of recording
SECAM on VHS {see also SECAM (VHS) and MESECAM
(VHS)}. SECAM can be transcoded to PAL and PAL-N.
SECAM Bottles The subject of SECAM "bottles" has been the
(Video) source of considerable confusion with regard
to VHS duplication. The failure of color
playback of SECAM VHS recordings has often
been blamed on the absence or presence of
recorded "bottles" in the SECAM video; when
in fact the compatibility problems are usually
the result of an interchange of tapes between
Standard or "French" SECAM and MESECAM
machines. The inclusion or deletion of
"bottles" in recorded SECAM video is not a
compatibility issue with regard to the
operation of VHS machines; since SECAM and
MESECAM VHS machines never demodulate the
SECAM chrominance information, and therefore
never make any use of the "bottles." Both
SECAM and MESECAM VHS machines will record
and play back SECAM "bottles." With regard
to VHS duplication, the need for recorded
"bottles" is dictated only by the design of
the viewers' television receivers. Most SECAM
countries, including France, have dropped the
requirement for vertical interval "bottles"
in their broadcast video {CCIR report 624-3}.
Unless a conflict exists that requires the
use of the horizontal lines that are normally
occupied by the "bottles" for recording
information such as teletext or other
vertical interval signals on VHS; including
the "bottles" signal in VHS duplicates will
do absolutely no harm and will assure
compatibility with the few receivers that make
use of this signal.
SECAM (VHS) Also called "French SECAM" or "Standard
SECAM." Only relates to VHS recordings.
A method of producing the color-under
chrominance information for recording and
playing back SECAM video on VHS by dividing
the two SECAM FM chrominance subcarriers by 4
during recording, and multiplying these
subcarriers by 4 during playback. Because
this method uses a completely different
scheme than that used in PAL VHS machines for
recording the chrominance information, this
method of recording SECAM video is most
commonly found on single-standard SECAM-only
VHS machines. Because of the availability of
pre-recorded VHS program material in France,
the consumer-base in France has not been
forced to resort to using PAL VHS machines to
view pre-recorded programs. Therefore,
SECAM-only (standard) VHS machines are
predominant in France. This is the basis for
the term "French SECAM" when used in
reference to VHS recording methods. Although
both SECAM (VHS) and MESECAM (VHS) machines
will record and play back SECAM color video,
there is no interchangeability of recorded
material for color playback between MESECAM
(VHS) and SECAM (VHS) machines. Color video
recordings that are interchanged between
MESECAM (VHS) and SECAM (VHS) machines will
play back in monochrome. PAL VHS recordings
are interchangeable with SECAM (VHS)
machines, but also for monochrome-only
playback. {See also MESECAM (VHS), SECAM
Bottles (Video)}.
SECAM-East See MESECAM (VHS). Relates only to VHS
(VHS) recordings.
French SECAM A colloquialism. This term is generally used
(Video/VHS) in the vernacular only in reference to VHS;
and in this instance, see SECAM (VHS). When
used in reference to receivers and tuners,
see L/SECAM (RF). When used in reference to
video, see SECAM (Video). "French SECAM" is
often referred to incorrectly as if it were
a completely unique video or VHS standard.
SECAM in France is unique only in the way in
which it is broadcast {see L/SECAM (RF)}.
The confusion regarding the term "French
SECAM" is exacerbated by the fact that France
uses a unique method for broadcasting both
video and audio; and thus, the tuners and RF
modulators in French VHS machines must follow
a slightly different design. However, the
SECAM video signals that are applied to
transmitters in France, and the demodulated
video that is produced by VHS machines in
France; conform to the single CCIR standard
that is used in all SECAM countries.
MESECAM (VHS) Middle-East SECAM. Also called "SECAM-East"
or "Pseudo SECAM." "MESECAM" relates only VHS
recordings, and does not relate to the SECAM
video standard itself. MESECAM derives its
name from the fact that the Middle-East has
many overlapping areas of both PAL and SECAM
broadcast coverage. MESECAM provides an
economical method of using the PAL circuitry
in a PAL/MESECAM VHS machine for recording
and playing back SECAM video. These machines
accomplish this by using the same
mixer/heterodyne circuitry that is used for
recording and playing back PAL video. This
method requires only slight modification of a
PAL recorder/reproducer, and thus it is the
most common and economical method of
recording and playing back both SECAM and PAL
video on these dual standard VHS machines.
Although both (standard or "French") SECAM
(VHS) and MESECAM (VHS) machines will record
and play back SECAM video in color, there is
no color interchangeability of recorded tapes
between standard SECAM VHS and MESECAM VHS
machines. The video quality of MESECAM (VHS)
is generally inferior to that of SECAM (VHS).
In countries where MESECAM (VHS) predominates
(such as in the USSR), you should
consider duplicating in PAL (VHS) since all
MESECAM (VHS) machines possess PAL playback
capability. {See also SECAM (VHS), SECAM
"Bottles"}.
Pseudo SECAM See MESECAM (VHS). Relates only to VHS
(VHS) recordings.
B,G/SECAM A transmission standard that specifies
(RF) channel spacings and bandwidths for
transmitters and tuners. Does not relate
directly to VHS recordings. The "B,G"
designation is of no interest in VHS
duplication. B,G SECAM transmission
assignments have been assigned to countries
in the Middle-East, Northern Africa, and at
the time of this writing to "East" Germany.
ME-SECAM (VHS) is predominate in these markets.
D,K/SECAM A transmission standard that specifies
(RF) channel spacings and bandwidths for
transmitters and tuners. Does not relate
directly to VHS recordings. The "D,K"
designation is of no interest in VHS
duplication. D,K/SECAM relates only to
spectrum and channel assignments for
broadcasting. D,K/SECAM is used in
Bulgaria, Czechoslovakia, Hungary, Poland,
and the USSR. A SECAM television
receiver purchased in Poland, for example,
will not receive television broadcasts in
France -- although the SECAM video in
both countries is exactly the same.
ME-SECAM (VHS) is predominate in these markets.
H,K1/SECAM A transmission standard that specifies
(RF) channel spacings and bandwidths for
transmitters and tuners. Does not relate
directly to VHS recordings. The "H or K1"
designation is of no interest in VHS duplication.
ME-SECAM (VHS) is predominate in these markets.
L/SECAM (RF) A transmission standard that specifies
channel spacings, visual modulation polarity,
and bandwidths for transmitters and tuners.
The "L" designation is of no interest in VHS
duplication. L/SECAM is used in France.
L/SECAM is unique in the way that it is
transmitted. Although the video is the same
as in all other SECAM countries, L/SECAM is
transmitted with the opposite video RF
modulation polarity (positive) from all other
systems, and the audio is transmitted using
AM rather than FM modulation. You
should use standard (frequency division) SECAM
VHS for this market.
Russian SECAM A colloquialism. Used in the vernacular only
(VHS) in reference to VHS. See MESECAM (VHS). (The
SECAM video that is broadcast in the USSR is
not unique and conforms to the single CCIR
standard.)
SECAM I,II, Early phases of development of the television
or III video standard that is now known simply as
(Video) "SECAM." Since the final form of modern
"SECAM" resulted from the optimization of the
model called "SECAM III," modern SECAM will
still occasionally be referred to as "SECAM
III."
SECAM IV A variant of early SECAM that was never
(Video) considered or implemented.
Soviet SECAM A colloquialism. Used in the vernacular only
(VHS) in reference to VHS. See MESECAM (VHS). (The
SECAM video that is broadcast in the USSR is
not unique and conforms to the single CCIR
standard.)
Standard See SECAM (VHS).
SECAM (VHS)
VHS Video Home System. Developed by Japan Victor
Company (JVC). A 1/2 inch helical scan video
cassette format where the luminance
information is recorded by FM means, and the
chrominance sideband information is converted
by either heterodyne or frequency division
methods to a lower frequency for direct
recording.
VHS SP VHS Standard Play. Refers to the linear
velocity of the video tape as it passes
through the transport. The "standard play"
speed for NTSC/PAL-M (525 line standards) is
33.35 millimeters per second, and for PAL/
PAL-N/SECAM/ME-SECAM (625 line standards) is
23.39 millimeters per second. Since the
amount of tape that is commonly loaded onto a
NTSC VHS cassette allows for 2 hours of recording
time in VHS SP mode, this speed is often
referred to as the "2 hour" mode.
VHS LP VHS Long Play. Refers to the linear velocity
of the video tape as it passes through the
transport. The "long play" speed for NTSC
is 16.67 millimeters per second, and for PAL/PAL-N
SECAM/ME-SECAM is 11.69 millimeters per second.
VHS LP speed is one-half (50%) that of VHS SP
speed. VHS LP is not commonly found in NTSC
countries outside of North America. Since the
amount of tape that is commonly loaded onto a NTSC
VHS cassette allows for 2 hours of recording time
in VHS SP mode, this speed is often referred
to as the "4 hour" mode. Because the LP speed
in PAL/SECAM is only slightly faster than EP
speed in NTSC, and because of the inherent
difficulties of recording in VHS PAL/SECAM;
the quality of PAL/SECAM VHS LP recordings is
generally unacceptable. You should
avoid the use of LP in PAL/SECAM.
VHS EP/SLP VHS Extended Play. Also called "SLP" for
Super Long Play. "EP" or "SLP" speed
does not exist in PAL/SECAM VHS.
The recording speed of VHS EP is one-third that
of the SP speed. Since the amount of tape that
is commonly loaded onto a NTSC VHS cassette allows
for 2 hours of recording time in VHS SP mode,
this speed is often referred to as the "6 hour"
mode.
* SuperNTSC is a trademark of Faroudja Laboratories
