From: mike@BRL.MIL (Mike Muuss)
Newsgroups: rec.video
Subject: Re: S-video input for Laser Disc player
Date: 20 Jul 92 19:56:15 GMT
Organization: The Internet


Bob Niland wrote:

> Hook your LD player to a "video" input and save the "S-video" input
> for your VCR/TV interlink (not that it buys you much there, either).

I have to take exception to the parenthetical remark:  if you have
a good VCR, and a well recorded tape, my own experience has been that
using the S-video output has resulted in substantially better final
picture quality.

For myself I have verified this by connecting both the composite and
S-video outputs of a VCR to both the composite and S-video inputs of a
Microtime TX-3FIT format transcoding 4:2:2 digital timebase corrector.
I observe the output of the TX-3 on a Sony PVM-1944Q fine-pitch monitor,
fed by both the composite and S-video outputs of the TX-3. Even using
the composite path to the monitor, the image quality is *substantially*
better when the TX-3 is fed from the S-video output of the VCR, as
opposed to feeding it from the composite output.  This makes a good
test setup, as the different paths can be checked by flicking a switch,
allowing good A/B comparison.  The same results can be observed by
omitting the TX-3 and going straight to the monitor, although results
are a bit harder to judge, owing to the time inaccuracies of the signal
seeming to blur the image slightly.

I reason for this I explained in my previous note:  analog videotapes
are recorded in Y/C form, not composite.  Avoiding one encoding and
one decoding step (where the intermediate (composite) format is of lower
overall bandwidth than Y/C) should generally give better results.

Whenever you have the option of taking Y/C output of a VCR, do so.
At least experiment with it, and see what looks better.  Have a friend
at a local TV station or computer graphics facility record you a tape
with SMPTE color bars and the "multiburst" pattern, so that you can make
reasonable accurate judgements of your system's performance by eye.
(If you have an LD player, these are on "A Video Standard" from Reference
Recordings, along with an explanation of how to use them).

It is quite reasonable to take the S-video output of your LD player,
feed it into the S-video input of your VCR, and then run S-video from
the VCR to the monitor.  By selecting the "S-video line in" setting on
your VCR, you can watch a LD.  The only drawback to this strategy is
that you have to turn on the VCR to use the LD player.  I have my own
system wired this way, and it causes no problems, and offers one
benefit: my VCR has a digital noise reduction (NR) circuit in it.  A few
LD's have enough video noise to make the NR artifacts less objectionable
than the noise itself, so on them I just click on the VCR's NR circuit,
and clean up the video from the LD.

On the subject of purchasing a LD player...

Having been trained as an engineer, I'm perhaps a bit more of a
technophile than some.  Before I buy equipment, I spend a lot of time
judging it subjectively, and then I make measurements to see if I can
explain what I observed.  When I was preparing to buy my LD player, I
brought along a 250 MHz o'scope, NTSC waveform analyzer, and NTSC
vectorscope, so that I could conduct accurate measurements.  Once I had
decided on the model I wanted (I picked the Pioneer CLD-91, because it
provided fairly acceptable video quality [for 'pro engineer standards]
at a price I could manage), the deal I made with the store was that I
would test the unit I was acutally going to purchase, and if it "looked
good" to me, and met manufacturers specs, then I'd take it.  Otherwise,
we would open another box and try again.

Needless to say, this operation was a bit of a spectacle. I had made
arrangements with the manager of the store *in advance*, so that the
staff was prepared for me to drag in my pile of equipment.  I came just
after lunch (their slowest hours) on their slowest day of the week
(Tuesday, I think).  Amusingly, there was a Pioneer rep from California
there that week, and he took copious notes as I announced my
measurements and made a few biting remarks.  A bit of a crowd gathered
to watch.  We were all having a good time, and I took the time to
explain to folks what each measurement was, and what it was good for. It
was not too surprising that along the way I sold two more CLD-91's for
the store, while I was putting mine through it's paces.  As it turns out,
the first carton we opened proved acceptable, and I've been very happy
with it.

[The store is Laserland in WhiteMarsh MD.  I have done business there for
several years, and I've been completely satisfied with them.]

If you take the time to educate your eyes (and ears), and shop around,
you can do very well, without spending a fortune...

	Best,
	 -Mike
Newsgroups: rec.video