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Digital Domesday Defies Doom
Hulver writes "The BBC Domesday project, originally completed in 1986 and under threat (as reported in this old slashdot story) has had its data recovered. The contents of the laserdiscs have been put on DVD, and new programs written so that PCs can access the data. Interestingly, most of the images and films were not recovered from the laserdiscs, but were instead re-digitised from the original analog films at a higher resolution than the laserdiscs contained. Full details of the recovered data are at the Public Record Office website."
laserdisc is, in fact, analog...so how can 're-digitised' be correct?
Sorry about the reply to my own post, but the article refers to Francis Bacon's shrieking pope paintings. Here's a link.
To make laws that man cannot, and will not obey, serves to bring all law into contempt.
--E.C. Stanton
Read your history and learn about the Domesday [sic] Book. It's not a mistake.
YFI
-uso.
Dreams, dreams, don't doubt dreams, dreaming children's dreaming dreams. Sailor Moon SS
Language drifts and changes. Pick up a copy Beowulf, circle AD 800. Chances are you won't understand a whole lot, it's written in old english. What with the great vowel shift, the meanings of most of those words have significantly changed. Now, instead of 1200 years, imagine what 100,000 years of language evolution would do to such a warning. That's why ANY warning they choose will probably be pictoral, not script.
To make laws that man cannot, and will not obey, serves to bring all law into contempt.
--E.C. Stanton
LOL , it's doomsday not "Domesday"
I think (and this will go down really well here) that the problem is of licensing. The copyright clearance obtained for the original project didn't include republication rights, so they're not able to republish the content in a different form without contacting all the copyright holders. That would be
expensive and timeconsuming, even if they could find all the information...
from your statement it seems you think that just because data is not digital, it will degrade.
it is actually the medium that degrades, data corruption is a side-effect. film is vulnerable to heat and light and laserdisc is vulnerable to scratching. the format of the data is irelevent.
you should also realize that just the act of digitizing data is degrading it. the digital version will always be a subset of the analog version. really the only upside to digital is the ability to make exact copies.
the only thing you can do is preserve the original in analog format the best you can, digitizing it once in a while whenever better digitizing technology is available.
bite my glorious golden ass.
But the book is a proper noun, so regardless of whether it's old english or not, that's still how it's spelled.
>whereas IIRC the resolution of laserdisc is only somewhat better than VHS and not as good as DVD.
Laserdisc stores infinite horizontal resolution, and carries a full NTSC (or PAL, or whatever you like) signal, which, if done properly, ensures most of the 525 (or 625) lines of resolution are on a disc without laser rot. According the the FAQ it's actually 420 lines, but since they are 100% wrong on the resolution of DVD (500 lines is NOT a standard NTSC DVD resolution and won't play back on a great number of players, PAL or NTSC, *ONLY* 480 is compatible, *NO* other vertical resolution is supposed to be playable), and they can't make up their minds about LD resolution (it also suggests 482 lines), I doubt it's validity on these measurements.
Knowing now that laserdisc and DVD vertical resolutions are virtually identical, and knowing that laserdisc stores more horizontal information, we seem to see that laserdisc is superior. However, being an analog composite signal, it has the usual drawbacks, such as poor chroma separation, noise, and quality -- the effect of all depends highly on your equipment (modern comb filters are nearing perfection) and disc quality (laser rot, scratches, etc).
But, balanced with the obvious MPEG artifacts found in crappily encoded DVDs, it can be a tossup. I'd probably take the DVD anyways, because there's a lot more tangible features it has over LD (portability and ubiquity being two big ones).
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
>It is analogue. That does not make it infinite.
i son/
Yes, it does make it infinite. In fact, that is the very DEFINITION of analog.
analog: <electronics> (US: "analog") A description of a continuously
variable signal or a circuit or device designed to handle such
signals. The opposite is "discrete" or "digital".
Continuously variable, of course, means infinite.
If it were finite (like digital) you would be able to discern points if the image were blown up large enough. As you increase the size of a laserdisc image, you can clearly see each scanline, but you will not be able to discern any horizonal points if the source were analog, ever. It will simply become a smear, so there is simply no point giving LD a horizontal resolution -- doing so is a complete insult to the very idea of an analog signal. It would be like suggesting your skin has a "resolution" by counting the pores. It doesn't work.
The fact is that with an analog signal, with better technology the signal can be improved to any point you like by improving the signal to noise ratio.
In contrast, the definition of digital:
<data> A description of data which is stored or transmitted
as a sequence of discrete symbols from a finite set, most
commonly this means binary data represented using electronic
or electromagnetic signals.
Which clearly specifies that digital is finite.
A sufficiently advanced analog device will always be better than a digital one, but far harder to design, and normally more expensive to record, so digital is preferred for its simplicity.
(Both definitions courtesy of The Free On-line Dictionary of Computing, © 1993-2003 Denis Howe)
>According to:
http://www.cs.tut.fi/~leopold/Ld/ResolutionCompar
laserdiscs are 560x360 which is worse than DVD's.
Actually, that's the letterbox resolution, which it specifies has the same amount of scanlines (vertical resolution) as DVDs. As I (and every EE in the world would also do so) have exlpained, because LD is analog, there is positively no point giving it a horizontal resolution. So, in fact, the quality of the picture, on a well designed, new (which they don't make, sadly) player can range from worse than DVD to better than DVD -- it's impossible to tell.
Now, when DVD gets more scanlines than NTSC video, we can reconsider this. But until then, the formats are relatively equivalent, and on my ancient LD player, (an old Pioneer industrial model) the output, apart from the usual analog signal problems (sparklies, etc) introduced by the aged crappyness of this player, is the same as DVD for quality.
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC