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In Reply to: how may lines of resolution are there in a letter boxed dvd image posted by Tom M on September 8, 2002 at 18:07:07:
Well let see... If NTSC has about 525 max resolution. Cut some to sinchro, and other coded signals and geometry hiden behind tube and you are left with less than 500. Now just measure how much of the screen is mising, get ratio from total hight of the screen, apply same ratio to this 500 lines, and you'll end up with less than bad VHS in 4:3 ratio.
But when they tell you that you have 400 resolution, this is not horisontal resolution like you think of resolution in computers.
TV signal have only horisontal resolution that compared to computer is vertical. So they are different. TV signal does not have vertical resolution that is actually horizontal in computers. Instead signal is defined as bandpass. This can be converted into frequancy, but it could be more or less than vertical resolution of the tube/display.
In this case one will cut down another. This is why TV resolution can not be expressed as it is. But most technical terms are alien to most people, so they come up with some resolution that actually does not tell real quality of the picture.TV and DVD that are rated both up to 400 resolution can actually have beter picture than one rated for 450. It is meaningles how they come to this resolution.
Some TVs have feature (forgot how they call it). But what it does, it detects how much of the picture is black under black, than increase horizontal frequancy to get more resolution, (this shrinks picture more) then increase vertical size of the picture to bring it to same size. In this way you can still have about 500 of horizontal resolution and letter box. But this lower bandpass, and how much you will be cut out depends of quality of the componnents. But it will be cut for sure.
If your TV does not have this feature, then measure what portion of screen is missing, and this is how much less horizontal resolution you actually have.
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Follow Ups
- Re: how may lines of resolution are there in a letter boxed dvd image - SysInfo 17:08:27 09/09/02 (0)
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