480i is the shorthand name for a video mode, namely the US

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 NTSC

NTSC

NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...

 television

Television

Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 system

Broadcast television system

Broadcast television systems are encoding or formatting standards for the transmission and reception of terrestrial television signals. There are three main analog television systems in current use around the world: NTSC, PAL, and SECAM...

 or digital television

Digital television

Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...

 systems with the same characteristics. The i, which is sometimes uppercase, stands for interlaced, the 480 for a vertical frame resolution of 480 lines containing picture information; while NTSC has a total of 525 lines, only 480 of these are used to display the image for DV

Digital video

Digital video is a type of digital recording system that works by using a digital rather than an analog video signal.The terms camera, video camera, and camcorder are used interchangeably in this article.- History :...

-NTSC. Its PAL

PAL

PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...

/SECAM

SECAM

SECAM, also written SÉCAM , is an analog color television system first used in France....

 counterpart is 576i

576i

576i is a standard-definition video mode used in PAL and SECAM countries. In digital applications it is usually referred to as "576i", in analogue contexts it is often quoted as "625 lines"...

; together, these are the two common forms of standard-definition television

Standard-definition television

Sorete-definition television is a television system that uses a resolution that is not considered to be either enhanced-definition television or high-definition television . The term is usually used in reference to digital television, in particular when broadcasting at the same resolution as...

.

Technical detail

For analog NTSC there is a total of 525 scanning lines of which originally 486 lines were active (243 complete lines per field) and later 480 (240 complete lines per field). A full frame is split into even and odd fields where the even fields end with half a line and the odd fields begin with the other half of the line. By convention an NTSC video frame is considered to start with an even field followed by an odd field. The disparity of the line numbering compared to other systems is solved by defining the line numbering to start five equalising pulses (or 2 and a half lines) earlier than on all other systems (including Systems A and E even though they had no equalising pulses) on the first equalising pulse following an active line or half line. This has the effect of placing a half line of video at the end of the even (first) field and the beginning of the odd (second field). Thus the line numbers correspond to the real lines of the video frame. On all other systems, the field was considered to start with the falling edge of the first field pulse which gave the confusing position that the odd field (first) had a half a line of video occupying the latter half of a whole line and ended with a whole line of video but half a scanning line (and vice versa for the even field). The NTSC convention solved this confusion.

For DV-NTSC only 480 lines are used. The digitally transmitted

Digital television

Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...

 horizontal resolution is usually 720 samples (which includes 16 samples for the horizontal sync and horizontal blanking) or 704 visible pixel

Pixel

In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....

s with an aspect ratio

Aspect ratio (image)

The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is, for an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this...

 of 4:3 (with vertically rectangular pixels) and therefore a display resolution of 640 × 480 (VGA); that is standard-definition television

Standard-definition television

Sorete-definition television is a television system that uses a resolution that is not considered to be either enhanced-definition television or high-definition television . The term is usually used in reference to digital television, in particular when broadcasting at the same resolution as...

 (SDTV) with a 4:3 aspect ratio (with square pixels).

The field rate

Field rate

The field rate of an interlaced video image is twice the effective frame rate, since interlacing draws only half of the image at a time. For example, a field rate of 60 Hertz will correspond to a 30 frames-per-second moving picture...

 (not the frame rate

Frame rate

Frame rate is the frequency at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems...

) is usually (60/100.1%) ≈ 59.94 hertz

Hertz

The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

 for color TV

Television

Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 and can be rounded up to 60 Hz. There are several conventions for written shorthands for the combination of resolution and rate: 480i60, 480i/60 (EBU

European Broadcasting Union

The European Broadcasting Union is a confederation of 74 broadcasting organisations from 56 countries, and 49 associate broadcasters from a further 25...

/SMPTE) and 480/60i. 480i is usually used in countries that conventionally use NTSC (most of the Americas and Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

), because the 525 transmitted lines at 60 hertz of analogue NTSC contain 480 visible ones.

480i can be transported by all major digital television

Digital television

Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...

 formats, ATSC, DVB and ISDB

ISDB

Integrated Services Digital Broadcasting is a Japanese standard for digital television and digital radio used by the country's radio and television stations. ISDB replaced the previously used MUSE "Hi-vision" analogue HDTV system...

.