Videos purchased in Europe cannot be played in the United States, the result of formatting differences across the Atlantic. North American VCRs and DVD players are formatted to play NTSC video. PAL is the standard in most of Western and Central Europe. The difference is not the encoding of the video, but the means in which the video is transmitted.
PAL and NTSC are analog systems of transmission, which means that the growth of digital television around the globe will eventually render this comparison moot.
History
PAL (phase alternating line) video is the result of the European electrical grid, which is 50 hertz alternating current (Hz AC). Power circuits in North America are 60 Hz AC, which provides electricity at a higher frequency that is incompatible with PAL video. Because a new system needed to be designed, engineers tried to create a system that addressed deficiencies with the American video protocol. They called it National Television System Committee (NTSC).
Function
The NTSC protocol calls for 525 scan lines (also called 480i), which is the number of pixel lines transmitted over a signal in standard definition. PAL signals read 625 scan lines (576i). Televisions read the signal and apply it to the number of pixel lines on their screen.
The lower scan-line number of NTSC leads to less color depth. The result is a less-than-true color broadcast, requiring tint control. This is why NTSC televisions are equipped with tint controllers and PAL are not.
Function
The switch to digital broadcasting in February 2009 marks the end of the NTSC standard. The creation of high-definition television sets has standardized the scan lines. High-definition broadcasts in both 720i and 1080i, thanks to a digital-broadcast protocol. This eliminates the confusion between current analog standards. In America, consumers receiving over-the-air broadcasts must use special converter boxes to convert the digital signal and display it on an analog television. People with digital televisions have converters installed inside of the unit to decode the signal for display.
American cable and satellite subscribers will be upgraded to digital converter boxes by their provider to prevent service from being interrupted.
Significance
Film rate also varies between PAL and NTSC. NTSC broadcasts at a faster rate of 30 frames per second, while PAL broadcasts at 25 frames per second, which is very close the film frame rate of 24 per second. The result is that NTSC broadcasts require a "pull-ahead" at a rate of five frames of broadcast per two frames of film. This results in 2.5 more broadcast frames than film frames. The film is essentially slowed down in order to fit the broadcast.
Significance
The legacy of PAL and NTSC remains, as many people still have non-digital televisions. The creation of high-definition television sets also changes the aspect ratio of televisions. Standard-definition NTSC broadcasts in a ratio of 4:3. This means that for every four pixels in width, there are three in height. PAL broadcasts at 1:1. Digital televisions, including high-definition, can still broadcast 4:3, but rely on the 16:9 ratio. While proportionately these are the same, it relies on a wider screen format in order to provide 16 pixels in width per nine pixels in height.
Misconceptions
PAL and NTSC have little to do with the region codes found on video games and DVDs. Region codes restrict play from geographic region to geographic region. When DVD players are set up, typically the user is asked what region it will be used in. This cannot be changed after it is answered. While often confused because of the nearly matching maps, the NTSC-PAL difference resides primarily in technology, not region codes.
Tags: NTSC broadcasts, scan lines, broadcast frames, converter boxes, creation high-definition, creation high-definition television