NTSC Video Format Explained
Table of Content
What does NTSC stand for?
NTSC is an abbreviation for National Television System Committee.
What is NTSC?
The NTSC is responsible for setting television and video standards used in North America, most of South America, and some other countries. The NTSC standard for television defines a composite video signal with a refresh rate of 30 interlaced frames per second. Each frame contains 525 lines and can contain 16 million different colors.
The term NTSC may also be used to describe any video, including digital video, formatted for playback on an NTSC TV. This generally includes any Standard Definition (SD) video with a vertical resolution of up to 480 Pixels and a horizontal Resolution no greater than 720, which also has a Framerate of 29.97fps.
NTSC is sometimes referred to as 525/60, about the total number of lines (including lines not in the Active Area) and approximate Fieldrate. Digital formats include only 480 of NTSC’s 486 visible Scanlines due to the need to guarantee mod16 Resolution, meaning it’s divisible evenly by 16.
The NTSC standard is incompatible with most computer video standards, which generally use RGB video signals. However, you can insert special video adapters into your computer that convert NTSC signals into computer video signals and vice versa.
|N T S C|
National Television System Committee
|Horizontal Frequency||15.734 kHz|
|Vertical Frequency||60 Hz|
|Color Subcarrier Frequency||3.579545 MHz|
|Video Bandwidth||4.2 MHz|
|Sound Carrier||4.5 MHz|
The first black-and-white NTSC standard for broadcast was developed in 1941 and had no provision for color transmissions. The entry of the United States into the war halted the civilian development of commercial television. In 1953 a second standard was issued, which allowed color broadcasting to be compatible with the existing stock of black-and-white receivers while maintaining the broadcast channel bandwidth already in use.
NTSC was the first widely adopted broadcast color system. After over a half-century of use. ATSC replaces the vast majority of over-the-air NTSC transmissions.
How does the NTSC video standard works?
The NTSC system specifies 525 individual horizontal scan lines for each image.
Here’s how it works:
- The scanning beam scans every other horizontal line, from the top of the image to the bottom, which equals one field.
- The beam completes one line at a 15,734.27 Hz horizontal scan rate. That’s 15,734.27 cycles per second!
- The beam shuts off at the end of the first field.
- Back at the top, the beam fills in the other half of the lines- the even-numbered lines.
- Every frame scans two fields.
- The two fields are displayed in immediate succession, creating the appearance of a single 525-line frame.
- The beam scans all the lines in a frame at 59.94 Hz. That is a vertical scan rate of almost 60 cycles per second. That rate is compatible with the alternating current (AC) electricity supply of 60 cycles per second found in those regions that use NTSC.
- Color, for NTSC video, is carried at 3.58 MHz.
- Sound, for NTSC video, is carried at 4.5 MHz.
Which countries use the NTFC system?
The following countries use the NTSC system for television broadcasting.
- Canada, NTSC broadcast to be abandoned by August 2013, simulcast in ATSC
- Mexico, By 2022, simulcast in ATSC will replace NTSC broadcast.
- The United States, by February 2011, simulcast in ATSC will replace NTSC broadcast.
Central America and the Caribbean
- Antigua and Barbuda
- The British Virgin Islands
- Cayman Islands
- Costa Rica
- Dominican Republic
- El Salvador
- Leeward Islands
- Netherlands Antilles
- Puerto Rico (USA)
- Saint Kitts and Nevis
- Saint Lucia
- Saint Vincent and the Grenadines
- Trinidad and Tobago
- The USA Virgin Islands
- Paraguay (until 2006 Paraguay used PAL)
- South Korea
- Republic of China (Taiwan)
- Union of Myanmar (Burma)
- North Korea (Propaganda station aimed at South Korea; domestic broadcasts use PAL)
- Cambodia (Historic; Cambodia now uses PAL)
- Vietnam (Historic; all of Vietnam now uses PAL)
- Thailand (Historic; Thailand now uses PAL)
- US Territories
- American Samoa
- Northern Mariana Islands
- Midway Atoll (a USA military base)
Other Pacific island nations
- Marshall Islands (in Compact of Free Association with the USA; USA aid-funded NTSC adoption)
- Micronesia (in Compact of Free Association with the USA)
- Palau (in Compact of Free Association with the USA; adopted NTSC before independence)
- Samoa (closely tied to American Samoa; USA aid-funded NTSC adoption)
- Tonga (USA aid-funded NTSC adoption)
Historic (used NTSC experimentally before adopting PAL)
- Fiji (Historic; used before 1989, Fiji has used PAL since 1990)
- Diego Garcia
- South Yemen (Historic; all of Yemen now uses PAL)
- United Kingdom (Experimented with a 405-line variant of NTSC in the 1950s and 1960s; dropped in favor of PAL)