Subject: Re: [Fwd: VGA cards and SE100]
       Date: Sat, 17 Jun 2000 14:29:21 -0400
      From: Terry Jones 

At the risk of telling all of you something you already know, here are a few
tips about capture cards (video overlay) and computer video cards and all their
interactions. Unfortunately many of these lessons were learned the hard way,
hope you do not have to.

NTSC video (and I apologize for those that might be PAL users on the list,
things are different for them and I don't know the actual numbers) uses a 60Hz
(not MHz, 60Hz or 60 times per second) vertical refresh rate. Your video card
should be set to do 60Hz vertical refresh to work best with the SE100. This is
not to say that it will not work at other settings, but you will almost
certainly experience a kind of "snow" on the display when you use a faster
(higher) refresh rate. Computer displays are not NTSC video and so they do not
normally have to stick to 60Hz vertical refresh. They try to refresh faster so
that there is less "flicker" noticed by the user.

SE100 cards work best when the display is set to 256 colours. It has to do with
one magic colour (that magenta) being a "transparent" colour. Unfortunately when
you have your display set to 16262 or 65535 or millions of colours (true colour
or 24 or 32 or 36 bit colour) then sometimes you do not get that perfect match
to the "transparent colour" and things do not show through. Stick to 256
colours.

SE100 cards work at either 640x480 resolution or 800x600 resolution. You will
not be successful at higher resolutions and you are not really getting any more
real resolution from your capture card. Truth is, even 800x600 doesn't really
buy you any more resolution than 640x480 since the SE100 really doesn't capture
at that high a resolution, and even if it did, there simply is not that much
resolution available in your NTSC signal. Period.

Resolution and colour depth are no brainers. Easy to set them in win31, win95/98
etc.

Refresh can be a nightmare.

Keep in mind that for most video cards, you set the refresh rate for EACH
resolution. So I may set it to 60Hz for 640x480 and then try to run at 800x600
resolution and find that I get snow because in reality at 800x600 my card may be
doing 72 or 75Hz refresh.

Setting refresh rates is difficult because of the variety of approaches to doing
it. Some video cards use a utility that sets the refresh rate in permanent
(flash) memory on the card so all you have to do is set it once (for each
resolution). Some video cards are built onto the motherboard of the computer and
things like the refresh rate are set in the CMOS or BIOS settings, either by
hitting a special key combination on startup, or using some other magic
keystroke or even a utility program to set BIOS settings. On some machines with
a seperate video card there is a utility program that has to be run each time
the computer boots. On these I have seen many ways to do things. Some you give
it 3 or four pairs of numbers that are different resolutions and different
refresh rates, others you run it once for each resolution. Other video cards try
to hide the technical details of refresh rates by selecting refresh rates for
you automatically when you tell it your  monitor type and they use the maximum
refresh rates that a particular model of monitor can handle (for best flicker
free computer display, unfortunately not for NTSC video overlay!) This is often
the case as we get into Win95/98 with more modern plug and play monitors and
newer video cards. They detect the monitor and set refresh rates to "optimal"
automatically. Optimal is not necessarily right for NTSC video overlay tasks,
their idea of optimal is minimal flicker for your eyes. There are usually ways
to override this, for example by using "card default" and then finding the
utility for your card that sets the card refresh rates for each resolution.
Other times you have to choose a model of monitor that only supports 60Hz
refresh (hopefully they tell you the refresh rates in your video driver).

The last thing, and one I just ran into recently that sucked a zillion hours out
of my life, is that some cards have a utility that enables the VESA feature
connector. I have seen that for the same video card, the companies win31 drivers
DID enable the VESA connector and the companies win95/98 drivers did not enable
the VESA feature connector.

The next two biggest problems I have are human intervention problems. It is
difficult to keep the "helpful" people that use the computer from changing
resolutions and refresh rates. They are sure you will be better off at 1024x768
so you can see more on the screen or at 75Hz refresh to stop that annoying
flicker, without knowing the implications for your video capture programs.

The other problem is usually the human ME problem doing upgrades in the off
season. Add a new card, change this, update that, then comes the ski season and
I have FUBARed the VJ setup in the off season upgrades.

To solve both these human problems, I dedicate computers to the task of video
jump. They get put away in the off season, and unless the hard drive fails, when
I turn them on in the spring they work and there have been no helpful users
installing software and making setup changes...

Sorry this got so long, but I hope this helps some...

Terry Jones