Resolution question..

[Master Yoda]

OK, i have asked this before on another forum, but i can never get a straight answer....

What is the resolution of vhs and tv??

[Joe Fenton]

That's a very involved question. The resolution depends on factors like bandwidth, filtering, and interlacing. But here's a very general chart (NTSC):

Source: horz x vert
VHS: 240 x 380 (there are more than 380 vertical lines, but they are interlaced, reducing the effective resolution)
LDP: 400 x 380
S-VHS: 480 x 380
Analog Satellite: 480 x 380
S-Beta: 500 x 380

TV's will show different resolutions (no more than the source) based on the type of filter they use. A simple low-pass filter to separate lum and color results in a display res of less than 300 horz. Using a notch filter or comb filter raises the display res to 400 to 500 horz, depending on the bandwidth and dot pitch of the monitor. If the TV is really smart and includes so kind of deinterlacing circuitry, the vert resolution can be higher than the effective values above, but no more than the absolute number of active lines (482 for NTSC).

So a poor TV shows 240 x 380 (matched to standard VHS).
A good TV shows 400 x 380.
A high-quality TV shows 500 x 440 progressive.

All the values given above can vary based on the quality of the design and parts used, as well as the source of the video.

[mf]

And you can capture at a max of 640x480 for NTSC and 768x576 for PAL.

[fccHandler]

I think it's like comparing apples and oranges. VHS and TV don't really have a "resolution" (as we use the term in a digital sense), because they're analog waveforms. A better way to phrase it might be "How much pixel resolution do I need to adequately represent this analog signal?" But then it gets ugly, because you have to start thinking about the Nyquist theorem and Kell factor and so on...

Ultimately I don't think there's one simple answer for this that's going to satisfy everyone. As for myself, I say when in doubt, overestimate. I have yet to see a standard VHS recording that couldn't be "adequately represented" at a resolution of 480 x 480. (IMHO, any more than that is overkill for VHS.) OTOH I hate SVCD, so I will generally capture my VHS at 352 x 480, and broadcast TV at 720 x 480, simply because those are NTSC DVD standard resolutions.

[Master Yoda]

So unlike digital source's like dvd,svcd etc which have set resolution tv and vhs dont asw there analog.... i see, ok that answers my question, thank you ...


One last thing though.Does a tv have a max amont of pixels it can display, as i have a divx that has a res of 1024 x 576 that i want to play on my xbox but i dont know is it would display on a ty properly.

[Soulhunter]

Originally posted by Master Yoda
One last thing though.Does a tv have a max amont of pixels it can display, as i have a divx that has a res of 1024 x 576 that i want to play on my xbox but i dont know is it would display on a ty properly.
Hint... (http://members.aol.com/ajaynejr/vidres.htm) ;)


Bye