SDTV resolution by nation; countries using 480i are in green.
Although related, it should not be confused with the analog "525 lines" resolution, mandated by CCIR Systems M and J and usually paired with NTSC color. This association explains why 480i is sometimes inaccurately called "NTSC", even though NTSC only exists in the analog domain.
Technical details
Interlaced scanning: display of odd (green) and even (red) scanlines, and line return blanking periods (dotted)
For analog NTSC, there are a total of 525 scanning lines per frame of which originally 483 lines were visible (241.5 visible lines per field + 21 lines of vertical blanking per field = 483 + 42 = 525 lines per frame) and later 480 (240 complete lines per field). [For quad video recording systems, the math suggests 15 transverse head passes, each consisting of 16 lines of video, are required to complete one field.]
A full frame consists of two fields. One field contains the odd-numbered lines and the other contains the even ones. 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 equalizing pulses (or 2 and a half lines) earlier than on all other systems, including Systems A (405-line) and E (819-line) even though they had no equalizing pulses, on the first equalizing 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.[3]
For DV-NTSC only 480 lines are used. The digitally transmitted horizontal resolution is usually 720 samples (which includes 16 samples for the horizontal sync and horizontal blanking) or 704 visible pixels with an aspect ratio of 4:3 (with vertically rectangular pixels) and therefore a display resolution of 640 × 480 (VGA); that is standard-definition television (SDTV) with a 4:3 aspect ratio (with square pixels).[4][5][6]
The field rate (not the frame rate) is usually (60/1.001) = 59.94 hertz for color TV and is often incorrectly rounded up to 60 Hz. There are several conventions for written shorthands for the combination of resolution and rate: 480i60, 480i/30 (EBU/SMPTE always use frame rate to specify interlaced formats) and 480/60i. 480i is usually used in countries that conventionally use NTSC (most of the Americas and Japan), because the 525 transmitted lines at 60 hertz of analogue NTSC contain 480 visible ones.
In each case of the use of the ‘60’ terminology, it is merely shorthand for 59.94, to differentiate it from 30 (29.97) or 24 (23.976).
Color information is stored using the YCbCrcolor space (different from NTSC that used YIQ) with 4:2:2 sampling (also different from NTSC) and following Rec. 601 colorimetry.
^"What means 480i? - AfterDawn". www.afterdawn.com.
^"Recommendation ITU-R BT.601-7, Studio encoding parameters of digital television for standard 4:3 and wide-screen 16:9 aspect ratios" (PDF). International Telecommunication Union. March 2011.
^Report 308-2 of the XIIth Plenary of the CCIR - Characteristics of TV systems.
^"rpsoft 2000 software". rpsoft2000.com. Retrieved 1 June 2015.
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This article is about the digital resolution For the analog NTSC color system see NTSC For the analog 525 line TV system see 525 line 480i is the video mode used for standard definition digital television 1 in the Caribbean Japan South Korea Taiwan Philippines Laos Western Sahara and most of the Americas with the exception of Argentina Paraguay and Uruguay The 480 identifies a vertical resolution of 480 lines and the i identifies it as an interlaced resolution The field rate which is 60 Hz or 59 94 Hz when used with NTSC color is sometimes included when identifying the video mode i e 480i60 another notation endorsed by both the International Telecommunication Union in BT 601 2 and SMPTE in SMPTE 259M includes the frame rate as in 480i 30 The other common standard definition digital standard used in the rest of the world is 576i It originated from the need for a standard to digitize analog TV defined in BT 601 and is now used for digital TV broadcasts and home appliances such as game consoles and DVD disc players SDTV resolution by nation countries using 480i are in green Although related it should not be confused with the analog 525 lines resolution mandated by CCIR Systems M and J and usually paired with NTSC color This association explains why 480i is sometimes inaccurately called NTSC even though NTSC only exists in the analog domain Technical details Edit Interlaced scanning display of odd green and even red scanlines and line return blanking periods dotted For analog NTSC there are a total of 525 scanning lines per frame of which originally 483 lines were visible 241 5 visible lines per field 21 lines of vertical blanking per field 483 42 525 lines per frame and later 480 240 complete lines per field For quad video recording systems the math suggests 15 transverse head passes each consisting of 16 lines of video are required to complete one field A full frame consists of two fields One field contains the odd numbered lines and the other contains the even ones 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 equalizing pulses or 2 and a half lines earlier than on all other systems including Systems A 405 line and E 819 line even though they had no equalizing pulses on the first equalizing 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 3 For DV NTSC only 480 lines are used The digitally transmitted horizontal resolution is usually 720 samples which includes 16 samples for the horizontal sync and horizontal blanking or 704 visible pixels with an aspect ratio of 4 3 with vertically rectangular pixels and therefore a display resolution of 640 480 VGA that is standard definition television SDTV with a 4 3 aspect ratio with square pixels 4 5 6 The field rate not the frame rate is usually 60 1 001 59 94 hertz for color TV and is often incorrectly rounded up to 60 Hz There are several conventions for written shorthands for the combination of resolution and rate 480i60 480i 30 EBU SMPTE always use frame rate to specify interlaced formats and 480 60i 480i is usually used in countries that conventionally use NTSC most of the Americas and Japan because the 525 transmitted lines at 60 hertz of analogue NTSC contain 480 visible ones In each case of the use of the 60 terminology it is merely shorthand for 59 94 to differentiate it from 30 29 97 or 24 23 976 Color information is stored using the YCbCr color space different from NTSC that used YIQ with 4 2 2 sampling also different from NTSC and following Rec 601 colorimetry 480i can be transported by all major digital television formats ATSC DVB and ISDB and on DVD See also Edit Television portalEnhanced definition television EDTV List of common resolutions 4320p 2160p 1080p 1080i 720p 576p 576i 480p 360p 240pReferences Edit What means 480i AfterDawn www afterdawn com Recommendation ITU R BT 601 7 Studio encoding parameters of digital television for standard 4 3 and wide screen 16 9 aspect ratios PDF International Telecommunication Union March 2011 Report 308 2 of the XIIth Plenary of the CCIR Characteristics of TV systems rpsoft 2000 software rpsoft2000 com Retrieved 1 June 2015 480i afterdawn com Retrieved 1 June 2015 Glossary 480i Retrieved from https en wikipedia org w index php title 480i amp oldid 1107009917, wikipedia, wiki, book, books, library,
