NTSC
NTSC (National Television Standards Committee) is a standard used in NTSC countries: USA, Antigua, Bahamas, Barbados, Belize, Bermuda, Bolivia, Burma, Canada, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Greenland, Guam, Guatemala, Guyana, Honduras, Jamaica, Japan, South Korea, Mexico, Netherlands Antilles, Nicaragua, Panama, Peru, Philippines, Puerto Rico, St. Vincent & the Grenadines, St. Kitts, Saipan, Samoa, Surinam, Taiwan, Tobago, Trinidad, Venezuela and Virgin Islands. It has the ability to display up to 525 lines of resolution. The engineers refer NTSC as Never The Same Colour because NTSC - Why do engineers lovingly refer to it as Never The Same Color.
The color subcarrier reference frequency must be absolutely stable, as any variation in frequency or phase will result in a color shift. The subcarrier frequency of 3.57954545 is not directly recorded on a videotape for example, or even fully broadcast for that matter. Instead only just 9 cycles (a very tiny sample) is included at the start of each horizontal line of the composite video signal. The 9 cycles of subcarrier reference is called appropriately the Color Burst. It re-syncs and keeps accurate the TV's or VCR's internal subcarrier frequency phase lock loop reference oscillator that must always be locked accurately to the source, be it broadcast or from videotape. Put another way, it re-calibrates the subcarrier reference at the beginning of every horizontal line. Consider that every second there are nearly 15,734 re-calibrations ! (525 lines x 29.97 frames/sec).
It sounds like this should be more than enough to keep the reference tightly locked, but alas, sometimes even this is not quite enough. Broadcast signals are subject to multi-path distortions (the signal arriving at the antenna at slightly different times due to parts of it being reflected off interfering objects). As the frequency is only re-calibrated at the start of each line, multi-path reflections can knock it out of phase by the time the scanning beam reaches the end of the line. The result: a changing color hue from the left side of the picture to the right...... Better tuners and directional antennas greatly reduce the effects, but ultimately, there's no way around it - NTSC shall be forever plagued with the problem. It's designed into the system and too late to change. PAL however, came along later and doesn't have these troubles.
Why is PAL so stable when it comes to Color Stability ?
PAL in part, came about as a result of NTSC's weakness in the area of color stability. It circumvented NTSC's inherent problems by inverting the color phase by 180 degrees on every other line. If the color drifted off by Plus 5 degrees on line 100 for example, then on line 101 the color drifted back minus 5 deg. since the color phase reference was inverted every other line. True, the color errors were still there, but the human eye and brain are wonderfully marvelous devices.... the image processing center of our brains integrate the interleaving lines smoothly all into one coherent corrected image. The effect is that phase shifts are effectively cancelled out using our human brain as a super high speed image integrating processor.
SECAM
SECAM (Sequential Color Memory) is used sparingly around the world and can be found in Albania, Benin, Bulgaria, Congo, former Czechoslovakia, Djibouti, Egypt, France, French Guiana, Gabon, Greece (also PAL), Guadeloupe, Haiti, Hungary, Iran, Iraq, Ivory Coast, Lebanon, Libya, Luxembourg (also PAL), Madagascar, Martinique, Mauritius, Monaco (also PAL), Mongolia, Morocco, New Caledonia, Niger, Poland, Reunion, Romania, Saudi Arabia (also PAL), Senegal, Syria, Tahiti, Togo, Tunisia, the former USSR, Viet Nam, & Zaire. This system uses the same resolution of PAL, 625 lines, and frame rate, 25 per second, but the way SECAM processes the color information is not compatible with PAL (or anything else on the planet for that matter.
http://youtu.be/a4T3OKStOXw
Playing a SECAM tape in a PAL VCR.
Since the line count and frame rates are similar, it will be only black and white, since PAL & SECAM process the chroma information differently. Conversely, the same will be true by attempting to play a SECAM tape in PAL equipment.
PAL/SECAM Recording times when converted to NTSC.
Since NTSC is recorded at 60 frames/sec as compared to PAL and SECAM's 50 frames/second, it stands to reason that NTSC will consume more tape per given amount of recording time.
PAL VS NTSC
DVDs are merely carriers of data files with compressed audio-visual information contained therein. This information can be placed on DVD in one of two resolutions; 720 x 576 pixels (PAL DVDs), or 720 x 480 pixels (NTSC DVDs), and with various frame rates (24, 25, and 30 frames per second are common). The DVD player itself takes this data file and formats it appropriately for display in either PAL or NTSC.
PAL DVDs have 576 pixels of vertical resolution versus 480 pixels of vertical resolution. That's a 20% increase in resolution for a PAL DVD as compared to an NTSC DVD. Increased resolution translates into a better looking image.
For widescreen movies, 16x9 enhanced PAL DVDs provide the highest resolution image, and are theoretically the version of choice. If the PAL version of a widescreen movie is not 16x9 enhanced, then the version of choice is a 16x9 enhanced NTSC DVD.
With video-based source material, there are two predominant worldwide formats; PAL and NTSC, which differ in both resolution and in frame rate. PAL is higher in resolution (576 horizontal lines) than NTSC (480 horizontal lines), but NTSC updates the on-screen image more frequently than PAL (30 times per second versus 25 times per second). NTSC video is lower in resolution than PAL video, but because the screen updates more frequently, motion is rendered better in NTSC video than it is in PAL video. There is less jerkiness visible. When video source material is transferred to DVD, it is usually transferred in the format it was created in - PAL or NTSC, and the subsequent image has either higher temporal resolution (more frames per second - NTSC) or higher spatial resolution (more lines per image - PAL).
CONVERTING NTSC TO PAL
When converting from NTSC to PAL, two things need to be accomplished. 480 lines of resolution have to be upconverted to 576 lines of resolution, and 30 images per second have to be downconverted to 25 images per second.
The resolution upconversion does not actually add any real picture information to the image, as you cannot create real picture information where none existed before. It does, however, make the picture viewable on a PAL display, and often results in a superficially better-looking image.
The frame rate conversion actually results in a loss of temporal resolution, as PAL has a lower frame rate than NTSC.
CONVERTING PAL TO NTSC
The converse situation applies to PAL to NTSC conversions. 576 lines of resolution are downconverted to 480 lines of resolution, and frames need to be inserted to go from the 25 frames per second of PAL to the 30 frames per second of NTSC. Once again, the resultant image is of less actual resolution than the original image, as information is discarded spatially and made up temporally.
2) What will happen if we purchase a TV set in Japan and switch it on in Malaysia??
First of all, Japan uses NTSC while Malaysia uses PAL. In order to switch it on in Malaysia, you'll need what is called a multisystem VCR and a multisystem TV, or a Digital Video Standards Converter and VCR, or a VCR with a built-in Converter.
How do I watch overseas videotapes?
Videotapes come in variety standards, each incompatible with the other. To watch videotapes from overseas that are not the same video standard as your own, you'll need what is called a multisystem VCR and a multisystem TV, or a Digital Video Standards Converter and VCR, or a VCR with a built-in Converter.
http://www.110220volts.com/FAG/WhatisNTSC.htm
