Real Resolution of a Standard TV?

[Glenn Chan]

DVD Players can't deliver more than 540 lines of resolution. From what I hear most only deliver 500 lines because of poor digital-->analog converters.

2- Best Buy TVs: "There are lies, damned lies, and product specs." The TV specs may be fudged to give a higher number. However, it should be possible for a TV to deliver than much resolution if you feed it a really perfect signal.

Did that answer your question Tim? (I'm not sure if I understood it correctly)

[Mike Rehmus]

Tim,

They can spec any value they want. Those numbers are presented without any statement as to how they achieved them. For all you know (unless the manufacturer states otherwise) they achieved those resolution numbers with a picture nobody in their right mind would want to view.

OTOH, a LCD or Plasma TV probably does make the resolution numbers they state as long as a perfectly synchronous input signal is presented.

Today, you have to recognize that they have Television, Extended definition Television (a pure marketing term) and High Definition Television.

Not only do you have to understand which class, but which input they used to achieve the resolution.

[Tim Frank]

Okay I understand, I was just thinkging well there has to be some difference in the TV's that say they are 325 lines of resolution and the ones that say they are 625...they wouldn't claim those numbers if they weren't trying to say something like "here's our low-end TV and our high-end one...buy the one with bigger numbers."

[Robert Silvers]

It is entirely possible for a TV to have 600 lines res. You might have to feed it from component input to get that.

I know one thing -- my Hdef tube might accept a signal at 1920x1080, but it only has 900 slits in the aperture mask so it really cannot exceed 900 wide. Stills looks terrific.

[Norm Couture]

TV sets are rated in "TV lines", which is the number or distinguishable vertical lines measured on a horizontal line the same length as the screen's height. Not completely accross the screen.
For instance, on a widescreen 16:9 TV set, they count the vertical lines accross the screen and multiply by 9/16.
For a standard 4:3 aspect ratio TV, multiply by 3/4.

On a $200 TV set, I wouldn't expect more than 400 TV lines.
On a $2000 Sony XBR, you'll find 800 advertised TV lines.
From a DV tape, you can't get more than 540 TV lines, mathematically: 720 x 3/4.

But it all depends of the TV's processor also...

Very complex indeed!

[Marc Young]

To further add to the confusion, please read:

http://www.maxim-ic.com/appnotes.cfm/appnote_number/750

Even in High Def DTV 1920 x 1080 (pixels), the TVL comes out to only 756. In NTSC, the number is 338, with an active pixel layout of 451 H x 483 V, according to the engineer who wrote this tech note. I believe his figure of 338 because this is what you can "practically" achieve with the best s-video cable, given the bandwidth limiting that takes place at the s-video output of the camcorder.

Thus, I don't know how some camera and monitor manufacturers come out with a resolution figure of 800 or 900. They are obviously not talking about TVL. In another thread in the DVX-100 forum, we began discussing what you could get out of the firewire spigot if you converted this to RGB or component video. Not owning such pro equipment, I'd like to know what those who work with top-tier broadcast cameras get through their monitors with mini-dv or dvcam tapes?

[Robert Silvers]

I use component video! S video is to be avoided.

[Mike Rehmus]

<<<-- Originally posted by Marc Young : To further add to the confusion, please read:

Thus, I don't know how some camera and monitor manufacturers come out with a resolution figure of 800 or 900. They are obviously not talking about TVL. -->>>

Thats the whole point. They are not discussing TVL, they are discussing the thoretical horizontal resolution of the system. Has nothing to do with NTSC lines.