FactPAL/NTSC i an analog concept. Since the advent of HD, everything about PAL/NTSC have become quite obsolete. If you plan to use HDMI cable to connect your LCD and DVD player, you don't need to worry about PAL and NTSC at all.
This is not entirely true.
NTSC and PAL/SECAM standards were introduced during the days of your cathode ray tube. They use the FIELD concept as against a movie film's concept of displaying a complete frame. Because of this fundamental difference in display methodology, all TV system (receivers, transmitters, cameras) use 'Frame Rate' as a primary foundation.
Though a digital TV can display a full image, the Frame Rate video standard, is still the foundation of the new Digital TV and HDTV standards. In both analogue and digital TVs images are displayed as frames. But there are some very basic differences.
How Frames Are Displayed in Analogue
Till some time ago we used to see TV using what is called a cathode ray tube (CRT). This is an analogue device. In all CRT monitors, the image is painted on the screen by an electron beam that scans from one side of the display to the other drawing thin lines. This scan is used to display the transitions in color, intensity and pattern, and each complete pass of the electron gun is called a FIELD. Analogue TV uses a process that relies on the brain's ability to integrate gradual transitions in pattern that the eye sees as the image is painted on the screen. Each picture or frame on a television screen is composed of 525 lines, numbered from 1 to 525. During the first phase of screen drawing, even-numbered lines are drawn - 2,4,6,8 and so on. During the next phase, the odd lines are drawn 1,3,5,7 and so on. The eye integrates the two images to create a single image. The fields are said to be interleaved together or interlaced. A frame or complete picture consists of two fields.
In flat panels such as LCD and plasmas, instead of using alternate fields, the fields are displayed sequentially. This is called progressive scanning.
NTSC & PAL/SECAM
There are two display standards followed around the world. One is followed in the US, Mexico, Canada, Korea, Japan and a few other countries. Termed NTSC, this is a TV standard developed in the U.S. in 1953 by the National Television System Committee. NTSC uses a Frame consisting of 486 horizontal lines in the active area and a frame rate of 29.97 frames per second (fps). The frame is interlaced, meaning it's composed of two individual fields with a Field rate of 59.94fps, usually termed as 60fps. Since this uses 60 fields per second it is also called as a 60Hz system.
The PAL (Phase Alternating Line) TV standard was introduced in the early 1960's in Europe. It has better Resolution than NTSC, having 576 lines in the active area of the frame. The Frame rate is 25fps, much closer to the 24 fps frame rate of a reel film. The Field rate is 50 or 50Hz.
How Frames Are Displayed in Digital TVs.
While displaying a traditional video content, digital TVs yet use the 30 or 25 frames per second to display images. These frames are displayed using either the Interlaced Scan or Progressive Scan method.
But what about Digital Content? Even here, countries are implementing the 30 or 25 frames per second concept.
In NTSC, when frames are displayed as an interlaced image (1080i), each frame is composed of two fields, with each field displayed every 60th of a second, and a complete frame displayed every 30th of a second. When the frame is displayed as a progressive scan format (720p or 1080p) it is displayed twice every 30th of a second. In both cases, a unique high definition frame is displayed every 30th of a second.
Similarly in PAL, when frames are displayed as an interlaced image (1080i), each frame is composed of two fields, with each field displayed every 50th of a second, and a complete frame displayed every 25th of a second. When the frame is displayed as a progressive scan format (720p or 1080p) it is displayed twice every 25th of a second. In both cases, a unique high definition frame is displayed every 25th of a second.
The Frame Rate is valid even when the connection between the DVD Player and the TV is purely digital.
Thus these standards will continue to rule the TV display methodologies for quite sometime. Yes, NTSC and PAL/SECAM will be replaced by ATSC and DVB standards around the world. When this happens everything will be purely digital and we can forget about de-interlacing and progressive scanning. But till that happens, we have to live with NTSC and PAL/SECAM standards for TV display. A lot of things have to change for that - from shooting, storage, film-to-video conversion, transmission, to finally the last mile connectivity and TV display methodology. .
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