Worldwide TV Standards NTSC PAL SECAM
Differing TV Systems mean Incompatible Tapes and Equipment
Viewers take TV for granted, but people with family and friends overseas sometimes find out the hard way that TV and video is not the same in all countries.
There are three main systems in service - Europe, Australia, and large parts of Asia use PAL, the Americas and Japan use NTSC, and France, Eastern Europe, some African countries and parts of the Middle East use one of the SECAM variants. In general, these are not compatible with each other and tapes made on one system will not play properly on equipment designed for another system.
How the TV Standards Babel Happened
The world got this via a cocktail of historical developments, vested interests and a healthy dose of nationalist politics... The engineering reasons are lost in the mists of time, but that is where it all started.
TV sets work by displaying a number of pictures in quick succession on the screen. In the early days of television it was deemed A Good Thing if the number of frames per second were simply related to the AC power frequency. Unfortunately two AC mains frequencies are used in the world, 50 and 60 Hz, which immediately divided the world into two camps.
As technology improved it was no longer necessary to keep this relationship between the number of frames per second and the mains frequency - when the Americans introduced color they changed their frame frequency to 59.94 Hz while the mains frequency remained at 60Hz.
Nevertheless, the world remains divided into countries that use 60 frames per second, primarily the USA and Japan, and those that have 50 frames per second, which is nearly everyone else. There is a corresponding difference in the number of horizontal lines which make up the picture - 60Hz systems tend to use 525 lines, and 50Hz systems use 625 lines.
The difference in the frame rate is the biggest incompatibility between standards, and is also the hardest to solve.
From Bad to Worse with Color...
The introduction of color was a new opportunity to create further divisions. The Americans were first to develop a color standard, with a system developed by the National Television Standards Committee. Though capable of good results in a closed environment it could exhibit hue variations in a broadcast system, so not one but two incompatible methods of improving things were devised, PAL and SECAM.
Amongst the countries based on 50Hz systems, PAL has been the most widely adopted. PAL is not the only color system in widespread use with 50Hz; the French designed a system of their own - primarily for political reasons to protect their domestic manufacturing companies - which is known as SECAM, standing for SEquential Couleur Avec Memoire.
SECAM was widely adopted in the former Eastern Block countries to encourage incompatibility with Western transmissions - again a political motive. SECAM is further split between several variants.
In general, since the field and scan rates are identical, viewers can expect to get a monochrome picture from a PAL video recording replayed on SECAM equipment, and vice versa. Much standard definition equipment sold in Europe after the year 2000 could display NTSC signals, since grey imports of Region 1 DVDs meant that viewing NTSC material in Europe opened a wider range of movies to consumers. However, the converse is not often the case – much consumer NTSC equipment cannot display or play back PAL signals.
Converting TV Standards between PAL and NTSC
If there is a need to view PAL material on NTSC equipment it is possible to send the tape to a company that can perform standards conversion, making a copy through a standards converter which turns a PAL signal into NTSC.
The process is not transparent. There is some loss of signal quality due to the copying process and there are usually some motion artefacts which appear as a juddering or jerky movement particularly visible on panning shots. However, the slight loss is often worth it to me able to watch a wedding video or the first steps of a child from faraway relatives.
Worldwide TV Standards Map
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