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Kosimo
March 16th, 2009, 11:11 AM
I beat a Guinness paint with a college :)
We were talking about Laserdisc, and he said that is totally analog. Yes, I know that the video content isn't digitally encoded, (some audio in some specific versions is anyway) but: Laserdisc has to use at some point digital technology in order to save date into the disc isn't it? I mean, the technology is Digital but is used to contain analog content.
Is like D-VHS, was an analog technology saving digital data.

So, is Laserdisc 100% analog? (This is what my friend says)
Or, is a Digital disc containing analog data? (This is what I say)

Please help!!!! :KS:KS:KS:KS:KS:KS

lisati
March 16th, 2009, 11:19 AM
Here's a quote from http://en.wikipedia.org/wiki/Laser_disc

The standard home video laserdisc is 30 cm (11.81 inches) in diameter and made up of two single-sided aluminum discs layered in plastic. Although read and featuring properties similar to a compact disc or DVD, a Laserdisc is for the most part an entirely analog system with video stored in the composite domain with analog sound and/or some form of digital audio. The first laserdiscs featured in 1978 were entirely analog but the format evolved to incorporate simple digital stereo sound to multi-channel formats such as Dolby Digital and DTS.

I'd say mostly analogue

Kosimo
March 16th, 2009, 11:30 AM
Here's a quote from http://en.wikipedia.org/wiki/Laser_disc


I'd say mostly analogue


Yes I've read this... But is hard for me to believe that the Optical Disc doesn't content zeros and ones, but an analog wave.
I still don't believe it!

Kosimo
March 16th, 2009, 11:31 AM
I think that this is the way how Laserdisc's surface is:

http://disc-continued.com/images/cd_microscope.jpg

Kosimo
March 16th, 2009, 11:33 AM
And this, is an analog Vinyl surface containing waves

http://blog.paddlefish.net/uploaded_images/packing_tape-759866.jpg

jespdj
March 16th, 2009, 11:52 AM
It's a bit strange to make a poll for a question like this, because reality is not determined by the opinion of people.

mips
March 16th, 2009, 12:13 PM
i'd say mostly analogue

+1

Kosimo
March 16th, 2009, 12:21 PM
It's a bit strange to make a poll for a question like this, because reality is not determined by the opinion of people.

True.
But I have no answer now and I want to collect people's opinion to compare it with mine.

mips
March 16th, 2009, 01:49 PM
True.
But I have no answer now and I want to collect people's opinion to compare it with mine.

Your or my opinions don't count, only the facts do.

Kosimo
March 16th, 2009, 02:14 PM
Your or my opinions don't could, only the facts do.

Can you confirm that the Laserdisc Surface contains analog waves? Do you have references?

damis648
March 16th, 2009, 02:28 PM
http://www.access-one.com/rjn/laser/legacy/ld96.html
That's what google turns up.

aaaantoine
March 16th, 2009, 04:47 PM
http://www.access-one.com/rjn/laser/legacy/ld96.html
That's what google turns up.

So the data is stored as a series of pits and lands. The pits do not consist of varying depth, so why is there a difference between this and binary (pit = 1, land = 0), the very essence of digital?

The data may consist of analog components, but the medium used to store that data is still digital.

mips
March 16th, 2009, 05:03 PM
Can you confirm that the Laserdisc Surface contains analog waves? Do you have references?

http://www.access-one.com/rjn/laser/legacy/ld96.html
http://www.blamld.com/DiscoVision/Disco-VisionReview.htm See menu on left of page.

You are not going to see things resembling sine waves stamped on the disc.
General info,
http://www.modeemi.fi/~leopold/AV/
http://www.modeemi.fi/~leopold/AV/HowLDsLookLike.html

mips
March 16th, 2009, 05:10 PM
So the data is stored as a series of pits and lands. The pits do not consist of varying depth, so why is there a difference between this and binary (pit = 1, land = 0), the very essence of digital?

The data may consist of analog components, but the medium used to store that data is still digital.

](*,)

So by your definition it would be safe to say thet barrel organs, musical clocks & musical boxes have a digital storage mechanism?

http://en.wikipedia.org/wiki/Barrel_organ
http://en.wikipedia.org/wiki/Musical_clock
http://en.wikipedia.org/wiki/Musical_box

ice60
March 16th, 2009, 06:03 PM
I beat a Guinness paint with a college :)
how did you manage to do that??!? i don't even know what that means, it sounds like you single-handedly beat two inanimate objects in a race lol. or am i misreading it??

damis648
March 17th, 2009, 12:49 AM
So the data is stored as a series of pits and lands. The pits do not consist of varying depth, so why is there a difference between this and binary (pit = 1, land = 0), the very essence of digital?

The data may consist of analog components, but the medium used to store that data is still digital.

This sums it up pretty well:



In over-simple terms, the video signal is represented by the pit-to-pit spacing and the audio is represented in the difference between pit/land length.

While pits and lands are digital-ish, the lengths of them are what counts. The variation in the lengths' of the pits define video, while the variation in the lengths' of the spaces between the pits define audio.

gletob
March 17th, 2009, 12:59 AM
how did you manage to do that??!? i don't even know what that means, it sounds like you single-handedly beat two inanimate objects in a race lol. or am i misreading it??

I think maybe he means a pint of Guinness bear with a Colleague. IDK my best guess.

In other news Pioneer just halted their manufacturing of laser disc players, thereby officially letting the format die in peace.

MikeTheC
March 17th, 2009, 02:29 AM
In other news Pioneer just halted their manufacturing of laser disc players, thereby officially letting the format die in peace.

Rest in peace, o carrier of un-digital data.

Kosimo
March 18th, 2009, 08:25 PM
Curious the poll result then...

issih
March 18th, 2009, 08:58 PM
As mips said, this isn't a matter for a poll, and the poll result certainly won't alter the facts. It is analog, those who voted otherwise are wrong. People, including me, sometimes make mistakes.

Simplistically, the length of the pits or the length of the gaps between them encode the data, as the length is a continuously variable, infinitely adjustable value, you are dealing with analog data.

dvd/cd's use the same storage mechanism but each bit is a predefined length around the track and is either a 1 if there is a level change or a zero if not.

Its exactly the same way you can store digital data on an analog magnetic tape, where a burst of tone for a set period of time is a 1, and the lack of that tone is a 0.

The medium is just a way to store data, that data could be analog or digital.

In my opinion you owe your colleague a pint of Guiness, sorry about that :)

aaaantoine
March 18th, 2009, 10:22 PM
](*,)

So by your definition it would be safe to say thet barrel organs, musical clocks & musical boxes have a digital storage mechanism?

http://en.wikipedia.org/wiki/Barrel_organ
http://en.wikipedia.org/wiki/Musical_clock
http://en.wikipedia.org/wiki/Musical_box

Point taken.

I will point out, however, that those musical mechanisms each have several tracks of data, and that each track represents a different note, whereas all the data for a laser disc is stored on a single track. So there is at least that key difference.

damis648 and issih's posts were more helpful in marking the distinction between analog and digital.

Kosimo
March 19th, 2009, 05:48 PM
Ok guys... :(

Kosimo
March 19th, 2009, 05:51 PM
So then... A question comes to my mind.. What about these discs with digital audio? How is then the audio recorded? using the same technology?

billgoldberg
March 19th, 2009, 07:13 PM
So then... A question comes to my mind.. What about these discs with digital audio? How is then the audio recorded? using the same technology?

Dude, seriously, google or wiki that stuff.

issih
March 20th, 2009, 01:37 PM
Its called sampling

http://en.wikipedia.org/wiki/Sampling_(signal_processing)

Its how we represent an analog signal as digital data. As you lower the sampling rate the amount of data needed to store the signal goes down, but so does the range of frequencies you can accurately reconstruct (aliasing).

The point of it all is that once its in a digital form we can use parity checks and other coding techniques to ensure that the data isn't corrupted, and therefore ensure that the signal is recreated as originally recorded, analog techniques are much more prone to degradation over time. At least that is the theory, in practice a compact disc sat in the sun for too long is as unuseable as a magnetic tape left near an electromagnet.

Kosimo
March 20th, 2009, 02:38 PM
Its called sampling

http://en.wikipedia.org/wiki/Sampling_(signal_processing)

Its how we represent an analog signal as digital data. As you lower the sampling rate the amount of data needed to store the signal goes down, but so does the range of frequencies you can accurately reconstruct (aliasing).

The point of it all is that once its in a digital form we can use parity checks and other coding techniques to ensure that the data isn't corrupted, and therefore ensure that the signal is recreated as originally recorded, analog techniques are much more prone to degradation over time. At least that is the theory, in practice a compact disc sat in the sun for too long is as unuseable as a magnetic tape left near an electromagnet.


Thanks for the elaborate answer. I will definitelly read the wikipedia link.