From: corwin@ensta.ensta.fr (Gilles Gravier)
Newsgroups: rec.arts.sf.movies
Subject: Re: Laserdiscs - general questions??
Date: 14 Aug 92 10:30:34 GMT
Organization: Ensta, Paris, France
NNTP-Posting-Host: ensta.ensta.fr

In article <5021@sersun1.essex.ac.uk> woocm@essex.ac.uk (Chris Wood) writes:
>
>	I've read alot about laserdiscs and the quality etc of
>them for some time. So I thought I might invest in one soon
>when I have some spare cash :-). Now I gather that there are
>a few different types of laserdisc player, i.e. I've seen some
>second hand ones, I just want to check a couple of points before
>buying one, and it ssems that on this newsgroup that many people
>have one....
>
>1) Are there different types? If so which is the best IYO.
>
>2) How easy is it to get laserdiscs in the U.K., are there any
>high-street retailers that also do discs or do most people get
>theirs by mail-order?
>

	Chris,

	There are 2 types of Laserdisk players... The mono-standard ones, and
dual standard ones...

	If you take a mono standard one, then choose it to be PAL (the UK and
European standard), not NTSC (US/JAPAN standard). But I sugest that you choose
a dual (PAL/NTSC) standard, so you'll be able to buy also US/JAPAN disks.

	Then there are several formats of Laser disks and related. There is
the compact disk (small 8cm and normal 11cm). Then there is the Videodisk,
15 or so cm and 30cm. Be sure your player reads all (usually the case).

	There are several types of encoding schemes. (well, of course, PAL
and NTSC). But also CAV (standard play) and CLV (extended play). In CAV, the
images are stored on the disk as on a Hrd Disk drive, i.s. the disk is 
formated in sectors, always the same number of sectors per track. The
advantage is that you can access each sector specifically, and thus stop on
a particular image and keep it displayed. The drawback is that there are
exactly the same number of sectors on the outside tracks then there are on
the inside tracks... So, density is lower on the outside... The disk
is not used to it's full capacity of storing information. In CLV, on the
opposite, the image is stored with the same density on all the tracks, 
linearly layed out, but not sectored. The advantage is that you store
twice the amount of info on a CLV than on a CAV disk... The drawback is
that since there are no sectors, you can't identify a specific image...
if you want to pause a film, your display goes blank (well, green or blue),
and the only information the player has is the track number... when you
unpause, you'll go back to the beginning of the track that was playing (to 
avoid any confusion, I mean by TRACK the equivalent of a TRACK or CYLINDER
on a floppy disk, not a TRACK as in a SONG). Also, in CAV, you can show
your film image by image, or slower, or faster, which is not possible in
CLV.

	If you want to make pauses on a CLV disk, you need a laserdisk player
with frame memory - VERY EXPENSIVE!

	If you want some slick features, some players are autoreverse... You
don't need to open the door, pick the disk, turn it around, insert it again,
and play again, when you come at the end of a side... Pleasant if you have
an NTSC CAV disk (say Terminator 2 collection), since there are only 30
minutes per side. A normal PAL/CLV record is one hour per side.

	Personally I have a SONY MDP 533, which has no frame memory, but
reads PAL/NTSC records, all formats of disks (audio/video). Works well!
It is not autoreverse. It has shuffle play for music and movies (not as
usefull when watching a movie, but for video clips, great!). I like it.


	My experience, as to finding records, is that in the UK, they are
not as common as, say, in France... But about 20 to 30 percent cheaper!
For example in the Virgin shops in London, you'll only find a choice of
about 20 disks, whereas in Paris Virgin Megastore, you'll find a few
hundred different disks!

	You might want to order directly from the US... but then, be
sure you have an NTSC compatible player and TV. Or you could try germany.
I have addresses in the US where you can order by phone. They'll ship to
you directly. I don't have any in germany.

	Does this answer your question?

	Gilles.

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Newsgroups: rec.arts.sf.movies