LD#92: "S-video" output on LaserDisc players              Edition: 28 Oct 92

re: > Does anyone have a definitive answer to whether there is a clearly
    > noticable improvement in picture quality when using an 'S' output from
    > a laser disk player as opposed to standard RCA jacks?
      
This needs to be added to the list of Frequently Asked Questions.

In two words, the answer is: usually no (with qualifications).
In a few more words:         if you can't tell, then it doesn't.

Y/C "consumer component" video (S-video) makes some sense on Super VHS tape
because the luminance (Y) and chrominance (C) information is independently
stored on the tape.  As long as Y/C separation is maintained from image
capture (camera/telecine), through storage (S-VHS) and display (TV/monitor),
it confers some benefits.  If at any stage the signal is converted to
composite ("video", or worse "RF"), the Y/C sep benefits are lost (although
regular VHS is so crummy that S-VHS via composite is still preferrable.
Once a signal is in the Y/C domain, additional cycles of compositing and
separating are best avoided.

In the IEC 857 (aka Philips/MCA LaserVideo, aka LaserDisc) standard, the
signal is already in composite form on the disc, not component.  Doing the
composite-to-Y/C separation step in the player, and having "S-video" Y/C
output on LD only makes sense if:

  - the player has digital TBC (time base correction) that operates AFTER
    the signal has been Y/C separated.  The composite output of these
    players is "re-composited" and is worth avoiding.  Some high-end players
    are architected this way.

For mid-range and low-end players, Y/C only makes sense if:

  - the Y/C separator circuit of the player is better than the one in the
    monitor/TV, and...

  - the rest of the monitor/TV (the one with the inferior Y/C sep) video
    circuitry is still good enough so you can tell that there is a difference.

If the monitor/TV does a poor job of Y/C sep, it is likely to have other
deficiencies that mask any difference between the two inputs.

          So LD "S-video" either doesn't matter,
          or it only matters when it doesn't matter :-)

The reality of mid-range and low-end LD Y/C is that some folks report that
Y/C is a tiny bit better than composite, some (like me) can't see a
difference, and some report that Y/C is slightly worse.  One correspondent
even changed his mind.  It depends on your particular equipment.  If you are
using a multi-standard (NTSC-PAL) LD player and multi-standard TV, you may
very well see better results with a Y/C connection, due to the poor NTSC
circuits in many multi-std PAL TVs.

With the exception listed below, no one has reported any startling
differences between composite video output and Y/C output on LD players.  I
have a Pioneer CLD-3070 player and Sony KV32XBR TV, calibrated with the
"Video Standard" LD.  I see no difference between composite "video" and Y/C
"S-Video" connects.

Theoretically, it is possible for the LD player to do a better job of Y/C
sep than the monitor.  The LD player can be tuned to the properties and
problems unique to LD, particularly in the area of rotational time-base
correction prior to Y/C sep.

There are a few Pioneer "Elite" players on the market that have Y/C output
that superior to their composite video.  Examples include the LD-S2, CLD-91
and CLD-92.  They have expensive TBC and sep circuits, to be sure, but that
is not why the Y/C output is better than the composite.  The composite video
is NOT tapped at the output of the TBC prior to Y/C sep.  It is synthesized
by recombining AFTER on-board Y/C sep.  You'll want to use the "S-Video"
outputs on these players.  Otherwise, you'll be performing Y/C sep TWICE.
Owners of these players consistently report that Y/C provides a better image
than composite.

One other note:  Using either Y/C or composite is definitely superior to
using the "RF" or "ANT" jacks, on any player.

Bottom line for me:  If Y/C output were an extra-cost option on LD players,
I would not pay more than $20 for it, and if not available at all, I would
not allow the lack of it to deter me from choosing a player.  I have it
today, and I'm not presently using it, even though I invested $20 in a Y/C
cable.

On the other hand, if you are for some reason taping LDs to S-VHS, always
play back the signal in the Y/C domain.  It's "component" on the tape, so
there's no point in recompositing and reseparating it.

Regards,                           PO Box 248
Bob Niland                         Enterprise
mailto:name@isp-name.domain        Kansas 
which, due to spam, is:            67441-0248 USA
rjn AT access DASH one DOT com

Unless otherwise specifically stated expressing personal
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