Q. I'm running 2 laptops & a dvd through a video switch to 2 lcd monitors & an XGA projector. I've connected everything with svideo cables (not VGA). When I'm using the laptops my lcd's are perfectly clear but the projected image through the XGA is incredibly blurry. Note that if I run the laptops to the projector with VGA the picture is clear. Is it the projector itselft or is this an issue that can't be resolved?
A. Not with S-Video.
If you run the projector straight from the VGA port then you'll get a very clear image (because the VGA connector was designed to handle computer graphics, though it can start to have problems when you push past UXGA) but you'll never get a good image from a computer using the TV out feature (S-Video just can't transmit a very clear image).
If the projector can handle PAL and you're outputting NTSC then switching to PAL might give you better image quality (as PAL tends to transmit with 576 visible scan lines while NTSC only transmits 480) although even then it'll be crap (just a bit less crappy than NTSC).
A VGA matrix would probably be better (and use the projector input select to get S-Video for the DVD player).
If you run the projector straight from the VGA port then you'll get a very clear image (because the VGA connector was designed to handle computer graphics, though it can start to have problems when you push past UXGA) but you'll never get a good image from a computer using the TV out feature (S-Video just can't transmit a very clear image).
If the projector can handle PAL and you're outputting NTSC then switching to PAL might give you better image quality (as PAL tends to transmit with 576 visible scan lines while NTSC only transmits 480) although even then it'll be crap (just a bit less crappy than NTSC).
A VGA matrix would probably be better (and use the projector input select to get S-Video for the DVD player).
What is different between a progressive scaned and none progressive sacned image?
Q. Do they effect on the image quality or not. Or is the the progressice scan effective in all tvs?
A. Progressive scan creates a complete image in one field (1/60 sec in the US) by displaying every line one after the other. The other method, called interlace, takes two fields to complete an image; the first field displays only every other line (the odd-nombered lines, e.g.), and the second field displays the remaining lines. Interlace scanning was used when television was first developed to reduce the required bandwidth needed to transmit the signal. For images that are stationary or slow-moving, your eye retains the image of the first field while the second field is being displayed, so you have the illusion of a complete picture with all the scan lines.
There are two problems with interlacing: 1) fast-moving objects will contain only half the number of lines in any position and will suffer loss of resolution. Edges of moving objects will appear jagged. 2) Cathode ray tube (CRT) displays have difficulty keeping the spacing between the two sets of lines exactly right. This is especially noticeable in text images (even stationary ones) and this is the reason that computer monitors are always progressive scan, and have been from the early days.
New TV sets have gone away from CRTs and use "fixed pixel" displays such as plasma, LCD or DLP. All of these displays are progressive scan; program material that is interlaced is converted to progressive by the electronics in the TV.
There are two problems with interlacing: 1) fast-moving objects will contain only half the number of lines in any position and will suffer loss of resolution. Edges of moving objects will appear jagged. 2) Cathode ray tube (CRT) displays have difficulty keeping the spacing between the two sets of lines exactly right. This is especially noticeable in text images (even stationary ones) and this is the reason that computer monitors are always progressive scan, and have been from the early days.
New TV sets have gone away from CRTs and use "fixed pixel" displays such as plasma, LCD or DLP. All of these displays are progressive scan; program material that is interlaced is converted to progressive by the electronics in the TV.
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