1015 lines
54 KiB
Plaintext
1015 lines
54 KiB
Plaintext
EXCHANGING VHS CASSETTES WITH FOREIGN VIEWERS AND
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USING VHS RECORDERS ABROAD
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INTRODUCTION
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Exchanging any video program with someone living abroad is complicated by
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the fact that most of the world does not use the American TV system.
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Regardless of the tape format used (i.e., VHS, SVHS, Beta, 8 mm, etc.)
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foreign video recordings cannot be played on an incompatible player, or
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displayed on an incompatible TV receiver.
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I will try to describe here some "tips and traps" of exchanging video
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recordings with foreign viewers and on using your NTSC camcoder in foreign
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countries. Since the VHS home recording system predominates at-present, I
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will describe here only the specific problems that relate to VHS.
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Since the SVHS format differs only in the way in which the luminance
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information is separated and recorded, all of the information below applies
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equally to SVHS. The details regarding the TV standards themselves are
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applicable to all recording formats.
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THE WORLD'S TV STANDARDS
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The color television system in use in the United States was adopted in
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1953, and because the United States was the first to widely implement color
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television, we have the oldest (though not necessarily the best) color
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television standard in the world. Considering the era in which it was
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devised, the system represents nothing short of genius on the part of its
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designers. Our TV system acted as the progenitor of all of the other TV
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broadcast systems to come.
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Our TV system is referred to as "NTSC" (National Television System
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Committee), and is used only in the U.S., Canada, Mexico, Central America,
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the UAE, Burma, the Pacific coastal countries in South America, and in
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parts of the Far East. When implemented, it represented a comprised effort
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to transmit color video within a comparatively narrow bandwidth allocation,
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while it maintained compatibility with the 100,000 or so black-and-white
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televisions that had already been sold in the U.S.
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The European countries began broadcasting color television in the late 50's
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and early 60's, and having had the dual advantages of time to improve on
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our system, and wider channel bandwidth assignments; adopted either the PAL
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(Phase Alternating Line) or SECAM (the French acronym for Sequential Color
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with Memory) color TV systems. Both the PAL and SECAM systems were
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intended to alleviated some inherent weaknesses in the early vacuum tube
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based NTSC equipment, although today their greatest advantage over NTSC
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stems from their wider bandwidth allocations. With the narrower channel
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bandwidths used in the U.S., it would be impossible for us to "switch" to
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either the European PAL or SECAM systems.
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Besides PAL and SECAM, there also exist two additional color TV standards:
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PAL-M, which is used only in Brazil; and PAL-N, which is used in Argentina,
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Paraguay, and Uruguay. PAL-M is a "hybrid" of both the NTSC and European
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PAL systems. It is an attempt to "fit" the PAL system within the same
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frequency spectrum that is used by NTSC. PAL-M uses the same
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specifications as NTSC for the black-and-white portion of the program
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(referred to in TV parlance as the "luminance" information), but it uses a
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modified form of the PAL system for its color (or "chrominance")
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information. Thus, NTSC and Brazilian PAL-M VHS recordings are
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interchangeable -- but only for black-and-white playback. While some PAL-M
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VHS machines are capable of playing NTSC, PAL-M televisions cannot
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reproduce the color portion of an NTSC program without using a special
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device known as a "transcoder." A transcoder takes the video program and
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reduces it to its color components - much like a television receiver does -
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and then reassembles these components in the new TV standard. Transcoding
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is a far simpler process than standards conversion, but it can only be used
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when the black-and-white standards of the two TV systems are the same.
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PAL-N on the other hand, uses the same black-and-white system as PAL and
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SECAM, but with a slightly modified PAL system for conveying the color
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information within a narrower RF bandwidth. PAL-N can be transcoded to or
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from either PAL or SECAM.
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TV STANDARDS CONVERSION
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The process of TV standards conversion involves accurately converting video
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information to a receiving rate that is different than the rate at which it
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is being transmitted. In NTSC, 30 (actually 29.97) "frames," or individual
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pictures, are transmitted each second. These frames are very similar from
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a conceptual standpoint to the individual frames in a motion picture. Also
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in NTSC, each frame is made up of 525 individual scan lines. PAL on the
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other hand has only 25 frames per second (5 fewer per second than NTSC),
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and has 625 lines per frame (100 more than NTSC).
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The world today has fortunately settled on only two line and frame
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rate standards:
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NTSC & PAL-M use 30 frames per second and 525 lines per frame.
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PAL, PAL-N, & SECAM use 25 frames per second and 625 lines per frame.
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A standards conversion from NTSC to PAL involves discarding 5 frames per
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second, while literally inventing 100 lines per frame. If the extra frames
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were simply thrown away, the resulting video would be so full of jerks and
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jumps that it would be unviewable, so a good standards converter will
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"interpolate" or average the information from one frame to the next. The
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standards converter does this by storing one or more frames in an
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electronic memory and then performing a comparison between the stored
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frames. The more memory -- the more accurate is this averaging process.
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The extra lines are either invented or discarded by a similar averaging
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system. The inner workings of modern TV standards converters are actually
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much more complex than described above: a modern converter uses high speed
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real-time computing techniques to detect and differentiate between moving
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and stationary objects in every frame of every scene in order to further
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reduce the appearance of jerkiness in the converted video.
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TV STANDARDS IN USE
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The following is a list of TV broadcast standards in use. This information
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is based on the XVIth Plenary Assembly of the Consultative Committee
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International Radio (CCIR), Dubrovnik, 1986.
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NTSC COUNTRIES:
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Bermudas
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Bolivia
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British Virgin Islands
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Burma
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Canada
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Chile
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Colombia
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Costa Rica
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Cuba
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Dominican Republic
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Ecuador
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Guatemala
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Haiti
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Honduras
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Jamaica
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Japan
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Korea (South)
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Mexico
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Montserrat
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Netherland Antilles
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Nicaragua
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Panama
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Peru
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Philippines
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Saint Christ. and Nevis
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Surinam
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United Arab Emirates
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United States
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Venezuela
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PAL COUNTRIES:
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*PAL-N Standard **PAL-M Standard
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Albania
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Algeria
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Angola
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Argentina*
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Australia
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Bahrain
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Bangladesh
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Belgium
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Botswana
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Brazil**
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Brunei
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Cameroon
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China (People's Republic)
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Denmark,
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with Greenland and Faroes
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Equatorial Guinea
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Ethiopia
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Finland
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Germany (Unified) (SECAM is currently being
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simulcast in what was formerly "East"
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Germany)
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Ghana
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Gibraltar
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Great Britain (England, Scotland, & Wales)
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Hong kong
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Iceland
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India
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Indonesia
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Ireland (Northern & Rep. of)
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Israel
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Italy
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Jordan
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Kenya
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Korea (North)
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Kuwait
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Lesotho
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Liberia
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Luxembourg
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Malawi
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Malaysia
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Maldives
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Malta
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Monaco
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Mozambique
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Netherlands
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New Guinea
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New Zealand
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Nigeria
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Norway
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Oman
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Pakistan
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Paraguay*
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Portugal
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Qatar
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Romania
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Sierra Leone
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Singapore
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South Africa
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Spain
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Sri Lanka
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Sudan
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Sweden
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Switzerland
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Syria
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Tanzania
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Thailand
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Tunisia
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Turkey
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Uganda
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Uruguay*
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Yemen (North & South)
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Yugoslavia
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Zambia
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Zimbabwe
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SECAM COUNTRIES:
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(Note: Except for France, either the MESECAM or PAL systems are the
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preferred standards for VHS interchange - refer to text below)
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Afghanistan
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Benin
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Bulgaria
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Burkina Faso
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Burundi
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Central African Rep.
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Chad
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Congo
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Cyprus
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Czechoslovakia
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Djibouti
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Egypt
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France
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Gabon
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Greece
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Guinea
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Hungary
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Iran
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Iraq
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Ivory Coast
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Lebanon
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Libya
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Madagascar
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Mali
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Mauritania
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Mongolia
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Morocco
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Niger
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Poland
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Rwanda
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Saudi Arabia
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Senegal
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Togo
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USSR
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Vietnam
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Zaire
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Occasionally you may encounter suffix letters after the TV standard
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specification, i.e., "PAL-B, PAL-I, SECAM D/K", etc. These suffixes refer
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to internationally agreed upon TRANSMISSION standards (promulgated by the
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CCIR), and are important only for TV receivers/tuners and transmitters/RF
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converters. Except for the two unusual standards of PAL-M and PAL-N, which
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are separate TV systems in their own right, these terms are irrelevant for
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the exchange of PRERECORDED VHS cassettes.
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Finally, there are two methods of recording SECAM on VHS. The first method
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complies with the accepted JVC "standard" for SECAM recording and is
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generally referred to as either the "Standard" or "French" SECAM method.
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(Because of the prevalence of Standard SECAM machines in France, the
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Standard SECAM recording method is often referred to as "French SECAM.")
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The second, and most common method, is referred to as "MESECAM," or Middle
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East SECAM. The "Middle East SECAM" method derives its name from the fact
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that the Middle East has a checkerboard of PAL and SECAM broadcast
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services. MESECAM was developed to allow a PAL VHS machine to record both
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PAL and SECAM broadcasts with only a very slight modification of the PAL
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circuitry. Unfortunately, not only is MESECAM video quality inferior to
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"Standard" SECAM VHS, but the method of recording SECAM video on the tape
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itself makes the recording incompatible with a "Standard" or "French" SECAM
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VHS machine -- SECAM recordings that are interchanged between MESECAM and
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Standard SECAM VHS machines will play back in black-and-white only. (For
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those who are interested in the technical reason for this incompatibility:
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MESECAM uses a heterodyne method for deriving the color-under subcarrier --
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the same method that is used for PAL and NTSC VHS, whereas Standard SECAM
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digitally divides the two SECAM FM chrominance subcarriers by 4. If the
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wrong reverse-process is used on playback, it results in the SECAM
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subcarriers being at the wrong frequencies, and the sidebands being too
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wide or too narrow.)
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With the exception of France, MESECAM is by far the most common VHS system
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used in SECAM broadcast countries. This is partly a matter of
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supply/demand economics, and partly because many of the countries that are
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broadcasting SECAM have had closed socialist economies in the past. As a
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result of these closed systems, most of the video software that has been
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obtainable has had to be smuggled in from the West -- and was recorded in
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PAL. Everyone who has a MESECAM VHS machine also has the ability to play
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PAL recordings, and with the addition of a simple transcoder, a SECAM TV
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receiver can display PAL recordings in color. If the intended recipient of
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a VHS cassette has the ability to play PAL recordings I suggest that you
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send recordings in PAL rather than MESECAM due to the differences in
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recording quality.
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BLANK VHS CASSETTES
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As described above, there are 5 color television standards in use
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throughout the world, and 6 ways of recording video on VHS. Without
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"standards conversion," the only foreign standard that can be played at all
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on an American VHS machine is PAL-M (the Brazilian standard), and then only
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in black-and-white.
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Fortunately, the situation is far less complicated with regard to BLANK VHS
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cassettes. VHS cassettes are mechanically identical in all TV standards.
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The only difference is that the tape SPEED is higher in NTSC (and PAL-M),
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and therefore, the recording time in NTSC is shorter for a given amount of
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tape.
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NTSC consumes tape at a rate of 2.0 meters per minute in standard play (SP)
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mode, and both PAL and SECAM consume tape at a rate of 1.42 meters per
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minute. Although it isn't necessary to take blank VHS cassettes along with
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you on a trip to Europe, you will need to do a little math to determine the
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recording time allowed on a blank European VHS cassette. The tape
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manufacturers generally make this easier for you by showing both the length
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(in meters) of the blank tape, and by designating the labelled European or
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American length with a code letter. American (NTSC) blank cassettes are
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marked with the letter "T" preceding the length, e.g., T-120; and European
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PAL/SECAM cassettes are marked with the letter "E" before the length, e.g.,
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E-180.
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An E-180 (180 minutes in PAL/SECAM) cassette will contain approximately 258
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meters of blank tape, and on this blank tape you can record: 258 divided by
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2 minutes of NTSC video; or 129 minutes of NTSC program.
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The following is a conversion table of tape lengths and recording times:
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Length code Blank tape length * NTSC/PAL-M time PAL/PAL-N/SECAM time
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----------- ----------------- --------------- --------------------
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T-20 44 meters 20 minutes 28 minutes
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T-30 64 meters 30 minutes 42 minutes
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T-40 84 meters 40 minutes 56 minutes
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T-45 94 meters 45 minutes 63 minutes
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T-60 125 meters 60 minutes 84 minutes
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T-80 165 meters 80 minutes 112 minutes
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T-90 185 meters 90 minutes 126 minutes
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T-120 246 meters 120 minutes 169 minutes
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T-130 266 meters 130 minutes 183 minutes
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T-160 326 meters 160 Minutes 225 minutes
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E-30 45 meters 22 minutes 30 minutes
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E-60 88 meters 44 minutes 60 minutes
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E-90 130 meters 65 minutes 90 minutes
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E-120 173 meters 86 minutes 120 minutes
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E-150 215 meters 107 minutes 150 minutes
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E-180 258 meters 129 minutes 180 minutes
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E-240 346 meters 173 minutes 240 minutes
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* Most tape manufactures add 3 to 6 meters of blank tape to their cassettes
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to allow for tape threading in the mechanism and for recording speed
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inaccuracies.
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EXCHANGING VHS RECORDINGS BETWEEN TV STANDARDS:
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There are only four possible methods of viewing a VHS recording in a
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foreign TV standard:
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1) purchase a multistandard converting VCR (such as the Panasonic AG-W1),
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2) purchase a VCR and television (and usually a voltage conversion
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transformer) designed for the foreign standard,
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3) "transcode" the video to the viewer's TV standard or,
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4) have the tape standards converted to the viewer's "home" television
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standard.
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If the exchange is between NTSC and PAL or SECAM countries, the first two
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options will involve an expense of around $2,000. The third option,
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transcoding, is inexpensive and quite popular in Eastern Europe where
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there are very few pre-recorded movies available in SECAM. (In fact, in a
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recent survey of Leningrad, USSR - a SECAM country - I was unable to find
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any SECAM recordings at the video rental shops - all of their recordings
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were in PAL. The Soviet Union now manufactures color televisions that
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eliminate the need for a transcoder by automatically detecting and
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transcoding PAL programs, such as the "Raduga" or "Rainbow" TV receiver
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manufactured by Elektornika in Leningrad.) Unfortunately, the transcoding
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method can only be used when converting video between two TV standards that
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have the same line and frame rate standards (the same black-and-white
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system). Transcoding is not an option when converting between PAL or SECAM
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and NTSC. The fourth option, standards conversion, is an economically
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appropriate method for an occasional exchange of video programs between
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NTSC and PAL/SECAM countries. Standards conversion of a VHS cassette will
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cost approximately $20 per hour of program, and this service can be
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provided usually with a 4 or 5 day turn-around to any location in the U.S.
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by firms such as Video Bridge (telephone: 800-877-4015).
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When having a VHS cassette standards converted, it is important to make
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sure that a digital process is being used for the conversion. The results
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of the older analog standards converters are inferior in all respects, and
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most laboratories today use digital "8 bit/2 field" - and more recently -
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"8 bit/4 field" systems. The biggest difference between the 2 field and 4
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field systems is in the accuracy of their motion interpolation. With the
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older 2 field systems, moving objects in the video, particularly background
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scenes during a camera pan, will occasionally appear to jump from point-to-
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point rather than moving smoothly. Although the video output from a 4
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field converter still represents something of a compromise, moving objects
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appear much more natural. (Since the typical cost of an 8 bit/4 field
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converter is $90,000, some laboratories have yet to upgrade their
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equipment.) The most rudimentary method of standards conversion involves
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literally pointing a TV camera of one standard at a TV display of another
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standard. This method produces results that are absolutely unacceptable to
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most viewers today.
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If you are sending a converted VHS cassette to Europe, it is also important
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to determine if the conversion service is recording audio using the Hi-Fi
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(sometimes called "HD") FM recording system. Hi-Fi audio capability is far
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more common in Europe than in the U.S., and some conversion services here
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in the U.S. try to skimp on this point.
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TV standards conversion today costs only a fraction of what it cost just a
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few years ago, and with the power of real-time computing performing motion
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detection, time-base correction, interpolation, noise reduction and image
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enhancement; the quality of converted video has improved to the point that
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the conversion process has not only become essentially transparent, but
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often the converted copies are superior to the original. In fact, most of
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the international programming that we see today was converted using the
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same technology that will be applied to your videos. If you intend to
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exchange video programs with someone living abroad, you can do so today by
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using any of the quality standards conversion services.
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The following glossary of terms is intended to assist you
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with the specialized terminology used in international
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television standards.
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Glossary:
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Glossary:
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Legend: The following designations have been used to avoid
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confusion, and to separate the definitions of terms
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that have multiple meanings:
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(Video): Applies to a video standard.
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(VHS): Applies to the method of recording or
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reproducing video with a VHS machine.
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(RF): Applies to radio frequency spectrum
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allocations, usually embodied in
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international treaties. Used to
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describe the design of television
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transmitters, receivers, and tuners.
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(Receivers): Applies to terms used to describe the
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design of television receivers.
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CCIR (Video) The French acronym for International Radio
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Consultative Committee. The CCIR has
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established recommendations for the video and
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transmission characteristics of all of the
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world's television systems. The term "CCIR
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video" is often encountered and is
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meaningless unless the television video
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standard to which this term applies is
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further specified. As a colloquialism, the
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term "CCIR video" is most frequently
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used in reference to the monochrome
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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.
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VHS EP/SLP VHS Extended Play. Also called "SLP" for
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Super Long Play. "EP" or "SLP" speed
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does not exist in PAL/SECAM VHS.
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The recording speed of VHS EP is one-third that
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of the SP speed. Since the amount of tape that
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is commonly loaded onto a NTSC VHS cassette allows
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for 2 hours of recording time in VHS SP mode,
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this speed is often referred to as the "6 hour"
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mode.
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* SuperNTSC is a trademark of Faroudja Laboratories
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