[comp.sys.sgi] CCIR 601, D1, Digital Video

rpaul@dasys1.UUCP (Rod Paul) (11/25/89)

I'm sorry to hear about the kludge; VideoCreator, that has just been anounced
on this newsgroup.

It it such a pity that SGI, who undoubtedly produce one of the finest platforms
for high-end 3D graphics, continue to neglect the field of BROADCAST video.

Just about all the SGI machines I've used have had some form of NTSC out, but
at such poor levels. All I've been using the CG2-boards for is rough tests.

To get some form of decent video out, I've had to use an Abekas A60 via 
ethernet, an option that I'm sure is not within the budget of many a user.

The one problem with the above method is the time it takes to convert RGB images
to the digital video format, CCIR 601, which the Abekas needs as input.

I must admit that dealing with digital video is the easiest, and that is why
I wonder why SGI doesn't seem to be addressing this avenue.

At SIGGRAPH this year I saw a 3rd party's product for displaying video in it's
own window on a graphics terminal. I wonder, how hard would it be to have a
device that accepted CCIR 601 in/out, and its' display memory accessable via
the GL routines lrectread/write and read/writeRGB? This option would speed up
conversion, and be able to tie into both hard-disk and digital tape recorders.

Sure this option would still be beyond the budget of most users, but you'd
have a fast way to record images with very high quality. Also, the more 
products/people using digital video will have some effect on bringing down the
cost of the format.

Well who knows, in 5 to 10 years everything may be HiDef, a whole new ball of
wax, but I sure hope I don't have to wait that long before getting decent
video out of an SGI platform.

charlie@celia.UUCP (Charlie Gibson) (11/27/89)

In article <8911250531.AA27913@dasys1.UUCP> rpaul@dasys1.UUCP (Rod Paul) writes:
>
>I'm sorry to hear about the kludge; VideoCreator, that has just been anounced
>on this newsgroup.
>
>It it such a pity that SGI, who undoubtedly produce one of the finest platforms
>for high-end 3D graphics, continue to neglect the field of BROADCAST video.
....

>To get some form of decent video out, I've had to use an Abekas A60 via 
>ethernet, an option that I'm sure is not within the budget of many a user.
>The one problem with the above method is the time it takes to convert RGB images
>to the digital video format, CCIR 601, which the Abekas needs as input.
>
>I must admit that dealing with digital video is the easiest, and that is why
>I wonder why SGI doesn't seem to be addressing this avenue.


Since Tektronix now offers an RGB-IN 601-OUT framebuffer in
their 88000 based workstations, and because those stations are causing
a bit of a rumble in the video world, I suspect that SGI will soon 
follow suit.  I know that this is not a new request -- we've been 
harping on them for over a year.

Vertigo also manufactures a hardware-based RGB-601 converter, but, alas,
they are only selling it in conjunctionn with their software.  I think
that their feeling is that it will boost software sales.  Also, unlike
the TEK board, I think that the conversion is slow -- like, I've even
heard as slow as 23 seconds per frame, which is far worse than doing
it in software.

If speed is a real problem, and you have an Abekas A60, you might want to
buy an A20, which is a real-time ANALOG RGB to 601 encoder.  I think that
it's only about $5000.  We have one, and you can snap frames onto the A60
as fast as you can display them on a frame buffer.  The quality is obviously
not quite as good as a purely digital transfer, but it sure beats waiting
around for some old tape machine to preroll and edit single frames.

-- 
Charlie Gibson -- Rhythm & Hues, Inc.
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