Sign in with
Sign up | Sign in
Your question

I was reading Laserdisc is actually analog...?

Last response: in Home Theatre Legacy
Share
Anonymous
October 16, 2004 9:33:06 AM

Archived from groups: alt.video.laserdisc (More info?)

Does this mean that just the optical lens is analog, but it converts
into binary just like CD's and DVD? Or is the actual analog signal is
just received fast enough to reproduce a direct analog line picture?
The article I read didn't explain it much.

If binary, is it an uncompressed image or compressed(similar to MPEG)
or what?

-Mike


--
half_eaten
------------------------------------------------------------------------
half_eaten's Profile: http://forums.yourdomain.com.au/member.php?userid=9
View this thread: http://forums.yourdomain.com.au/showthread.php?t=50403
Anonymous
October 16, 2004 7:37:43 PM

Archived from groups: alt.video.laserdisc (More info?)

"half_eaten" <half_eaten.1e7u1j@no-mx.forums.yourdomain.com.au> wrote in
message news:half_eaten.1e7u1j@no-mx.forums.yourdomain.com.au...
> Does this mean that just the optical lens is analog, but it converts
> into binary just like CD's and DVD?

Laserdisc video is fully analog. The pits and lands on the disc vary in
size and spacing. It is not a 1/0 binary process.

Here's the official laserdisc FAQ.

http://www.access-one.com/rjn/laser/laserdisc.html
Anonymous
October 16, 2004 8:04:47 PM

Archived from groups: alt.video.laserdisc (More info?)

>Does this mean that just the optical lens is analog, but it converts
>into binary just like CD's and DVD?

No. It means that the information encoded as pits and lands is dynamic instead
of being in a binary sequence.

The whole signal in LaserDisc is frequency modulated with seperate carriers for
audio and video and the FM signals are expressed as pits and lands of various
sizes and arranged in a linear sequence. It should also be noted that the disc
rotation speed has a direct effect on how the LD player can remodulate the
video signal for display on your television, which further proves that the pit
and land pattern is linear. CAV discs for NTSC must always rotate at 1800 RPM
to maintain the 60 Hz refresh, while CAA/CLV discs for NTSC must always
precisely vary the speed between 1800 RPM and 600 RPM to maintain a video
signal with 60 Hz refresh.

With digital, the pits and lands are fixed in size and expresses ON and OFF
sequences which are written in a mathematical modulation pattern (like 8-14
modulation for CD) and arranged in a block sector format strategy. Block
sector formatting, as opposed to linear formatting, provides an extra layer of
protection against read errors from a damaged disc. The information read from
the disc has to be reassembled into a linear format within the player
electronics.

The whole idea of reading is all the same, but it's zero-crossings of an FM
signal that is expressed with LaserDisc as opposed to I/O sequences with CD and
DVD. - Reinhart
Related resources
Anonymous
October 17, 2004 7:42:33 AM

Archived from groups: alt.video.laserdisc (More info?)

Roger Blake wrote:

> Hey, kid! Laser disc hails from the late 1970s! There was no such
> thing as digital audio back then!

So all those laserdiscs I play through my Yamaha Z1
receiver via the Ac3 connection from my Pioneer
CLD-D704 and the Yamaha reports digital 5.1 sound
don't exist?


drc :) 
Anonymous
October 17, 2004 8:39:14 AM

Archived from groups: alt.video.laserdisc (More info?)

"Darrel Christenson" <darrel.christensen@comcast.net> wrote in message
news:JSlcd.194825$wV.41016@attbi_s54...
> Roger Blake wrote:
>
> > Hey, kid! Laser disc hails from the late 1970s! There was no such
> > thing as digital audio back then!
>
> So all those laserdiscs I play through my Yamaha Z1
> receiver via the Ac3 connection from my Pioneer
> CLD-D704 and the Yamaha reports digital 5.1 sound
> don't exist?
>
>
> drc :) 
>
>

Not on disks from the early days of the format. It was only the last dying
breath of LDs that they had DD or DTS releases...
Anonymous
October 17, 2004 5:18:11 PM

Archived from groups: alt.video.laserdisc (More info?)

"Biz" <biznospam@notatt.net> wrote in message
news:SHmcd.1435$OD2.226@bgtnsc05-news.ops.worldnet.att.net...
>> > Hey, kid! Laser disc hails from the late 1970s! There was no such
>> > thing as digital audio back then!
>>
>> So all those laserdiscs I play through my Yamaha Z1
>> receiver via the Ac3 connection from my Pioneer
>> CLD-D704 and the Yamaha reports digital 5.1 sound
>> don't exist?
>
> Not on disks from the early days of the format. It was only the last
> dying
> breath of LDs that they had DD or DTS releases...

PCM digital audio was added to the laserdisc format in the mid-80s.
Anonymous
October 18, 2004 12:38:46 AM

Archived from groups: alt.video.laserdisc (More info?)

The video IS analog and ALWAYS HAS BEEN analog, FM encoded just like the
radio in your car. In the mid-80's they decided to take a section of the
bandwidth and encode a digital PCM bitstream there, FM encoded digital PCM.
Then in the 90's Dolby decided to encode on the right analog audio channel
the AC-3 bitstream. The players output the raw audio analog RF signal, the
AC-3 RF demodulators filter and demodulate the right channel to get a AC-3
bitstream. DTS decided to use the PCM bitstream, DTS replaced the stereo
PCM sound with their DTS encoded bitstream.

Yes, changes were made in the audio to try to keep LD alive with the average
consumer but the video always stayed analog.

Kurtis

"Darrel Christenson" <darrel.christensen@comcast.net> wrote in message
news:JSlcd.194825$wV.41016@attbi_s54...
> Roger Blake wrote:
>
> > Hey, kid! Laser disc hails from the late 1970s! There was no such
> > thing as digital audio back then!
>
> So all those laserdiscs I play through my Yamaha Z1
> receiver via the Ac3 connection from my Pioneer
> CLD-D704 and the Yamaha reports digital 5.1 sound
> don't exist?
>
>
> drc :) 
>
>
Anonymous
October 19, 2004 2:29:31 PM

Archived from groups: alt.video.laserdisc (More info?)

On Sun, 17 Oct 2004 03:42:33 GMT, Darrel Christenson
<darrel.christensen@comcast.net> wrote:

>Roger Blake wrote:
>
>> Hey, kid! Laser disc hails from the late 1970s! There was no such
>> thing as digital audio back then!
>
>So all those laserdiscs I play through my Yamaha Z1
>receiver via the Ac3 connection from my Pioneer
>CLD-D704 and the Yamaha reports digital 5.1 sound
>don't exist?

All facetiousness aside, in a limited respect I suppose that's
technically correct. At least when refering to the disc itself and
the signal at the pickup. Unlike CD & DVD, the digital elements
(PCM,AC3,DTS) must be modulated onto the FM carrier for storage on the
LD where the native signal is analog. So, yeah... up until the demod
stage I guess you could say those digital signals don't exist!
;-)
-K

--
To reply via email: this ID @<a well known service related to yodeling>.com
Anonymous
October 23, 2004 2:05:20 AM

Archived from groups: alt.video.laserdisc (More info?)

On Sun, 17 Oct 2004 03:42:33 GMT, Darrel Christenson
<darrel.christensen@comcast.net> wrote:

>Roger Blake wrote:
>
>> Hey, kid! Laser disc hails from the late 1970s! There was no such
>> thing as digital audio back then!
>
>So all those laserdiscs I play through my Yamaha Z1
>receiver via the Ac3 connection from my Pioneer
>CLD-D704 and the Yamaha reports digital 5.1 sound
>don't exist?
>
>
>drc :) 
>


Sorry to burst your bubble. The Dolby Digital 5.1 soundtrack on
LaserDisc is encoded as an RF signal on the LaserDisc. That is why
you need an RF demodulator to take the RF signal and unpack it into
the Dolby Digital signal, which is then decoded by the AC-3 decoder.

Blaine
blam1@oz.net
http://www.blamld.com
Anonymous
October 23, 2004 7:26:31 PM

Archived from groups: alt.video.laserdisc (More info?)

>Sorry to burst your bubble. The Dolby Digital 5.1 soundtrack on
>LaserDisc is encoded as an RF signal on the LaserDisc.

The Yamaha RX-Z1 as well as the successor RX-Z9 are one of the few receivers
sold today that have an internal AC-3 RF demodulator built-in.

http://www.yamaha.com/yec/products/RECEIVER/RX-Z1.htm

http://www.yamaha.com/yec/products/RECEIVER/rxz9/RXZ9.h...

The Denon AVR-5803 and its replacement AVR-5805 also have an AC-3 RF
demodulator integrated.

Here are rear panel photos.

http://www.usa.denon.com/catalog/photo.asp?s=home&p=AVR...
21302.jpg&c=2

http://www.usa.denon.com/catalog/photo.asp?s=home&p=AVR...
Back.jpg&c=2

I would advise Darrel Christenson to double check his connections.

On the player, make sure the cable is connected to the AC-3 RF out, not the
PCM/Digital out. Check the labeling of the ports and connect only to whatever
indicates it as an AC-3 **RF** feed.

On the receiver, make sure that the cable is connected to the "LD RF (AC-3)"
port located on the back left corner of the receiver. This port will be on top
of all the digital ports. - Reinhart
!