Re: 2 questions

[dempson@actrix.gen.nz (David Empson)]

JB <jbcole@ix.netcom.com> wrote:

> 2 questions:
> 
> what exactly does the video overlay card do?

If you have a IIc, this is a moot point anyway.  :-)

A video overlay card takes an external video signal as input (e.g. from
a video recorder or camera), and superimposes a computer-generated image
on top of it (with transparent areas as appropriate).  The resulting
image can then be sent out to a video recorder or monitor.  You can also
connect a IIgs RGB monitor to it.

The most obvious application is for adding subtitles to a video.  You
would need two VCRs (or a camera and VCR) to do this.  Another
possibility is to display external video in a window, in a rather
limited manner.

The overlay card is quite easy to use, because almost any software will
work with it.  It works best with programs like HyperCard IIgs or
HyperStudio, where the user has full control over the screen display.

A "key colour" can be selected using the software which controls the
card: any areas displayed in this colour will be transparent, allowing
the external video through.

The video overlay card can be used on a IIgs or an enhanced IIe.  It
will not be quite as flexible on the IIe, because the video modes are
more limited.

One interesting point to note, however: the video overlay card
implements the IIgs graphics modes, so a IIe can generate Super Hi-res
graphics displays if this card is installed.  I don't know if any
software is able to take advantage of this.

> Can I use a IIgs monitor on a IIc?

Not with currently available hardware, but it is possible in theory if
the correct interface was available.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand