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FAQ - What is Resolution (Active Lines)? (Historical Purposes)

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Updated late 2017. 3803 Previous views.

What is the relative "resolution" of various pieces of hardware and TV signals? These should probably be called active scanning lines, not resolution.

480i (Standard Definition - SD)

NTSC broadcasts are 480i.
DVD players, without progressive scan, provide signals at 480i.
The information on commercial DVDs is stored at 480i.

480P (Enhanced Definition - ED)

P stands for progressive scan - this can provide a smoother image.
Progressive Scan DVD players output 480P after the original 480i signal has been deinterlaced.


Some CRT-based HDTVs provide the option to "convert" incoming SD signals to 540P.

The following are High Definition:


This is High Definition programming.
HDABC, HDFox and some other broadcasters broadcast in 720P.
Some HDTVs do not "accept" 720P signals, so the STB needs to provide 1080i output in order to see these signals on those TVs.
Component Video Cables (or DVI/HDMI/Firewire) are necessary to carry these High Definition signals

768P, 788p 1024P

These are not broadcast formats, however, the native resolution of quite a few HDTVs is as indicated above. All incoming signals are converted to this native display format. See the FAQ on Native Display Resolution.


This is the most common High Definition format.
Component Video Cable (or DVI/HDMI/Firewire) can carry 1080 lines.


This is the highest High Definition format.


Ultra High Definition - 3,840 x 2,160 pixels.

P - Progressive - means that the entire image is "painted" on the screen in one step.

i - Interlaced - means that the image is "painted" on the screen in two steps - first the odd lines, then the even ones. This is done so quickly you don't usually notice, the same way you don't notice that movies are actually 24 still images per second. CRT-based TVs are the only TVs that display interlace. All fixed pixel displays display progressive scan.

The horizontal resolution (vertical lines) is limited typically by the type of HDTV.

Direct View CRTs - 700 - 1000 typically
7" CRT-based RPTVs - 1000-1200 typically
Fixed pixel displays - look at the specs - typically 1200-1400.
1080P HDTVs typically have 1920 vertical lines.
4k UHD TVs typically have over 8 million pixels.

Please PM 57 if you have any comments or suggestions for this post.'
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