IDM Mailing Archive

+------ grievous iv - gymkata! wrote:

quoted 3 lines but does it compress the information? will people _buy_ it? personally,

> > but does it compress the information? will people _buy_ it? personally, > i hope not, i'm sick of the format-change-of-the-year games.

+----- I read somewhere, in a technical article, that DVDs main asset in it's storage capacity was not data compression but a laser that had a much more focussed beam and that the laser light was at a different wavelength than the regular laser companies now use for scanning CDs. Can someone with more info confirm or trash this speculative opinion? I also thought that data compression often leads to all sorts of problems in a playback mode. Alec McKay

On Thu, 24 Oct 1996 10:34:52 -0400 (EDT), you wrote:

quoted 6 lines I read somewhere, in a technical article, that DVDs main asset in it's

>I read somewhere, in a technical article, that DVDs main asset in it's >storage capacity was not data compression but a laser that had a much >more focussed beam and that the laser light was at a different wavelength >than the regular laser companies now use for scanning CDs. > >Can someone with more info confirm or trash this speculative opinion?

I have posted about this before but once again, basically DVD is a fuck off storage medium which consolidates various technological advances ie shorter wavelength laser more closely packed 'tracks' double 'depth' double sided The first implementation doesn't use all of these technologies but the the double depth double sided ones wich are about another year off hold 17+ gigabytes... There have been proposals to vastly improve improving the 16bit 44khz CD standard to a 24bit 96kHz standard to soak up some of that extra capacity which is not a bad thing IMHO as this still leaves 2+ hours to fill. I'm sure someone knows more about it than I do on this list. Not that it's relevant or anything. g.

quoted 13 lines +------

>+------ >grievous iv - gymkata! wrote: >> >> but does it compress the information? will people _buy_ it? personally, >> i hope not, i'm sick of the format-change-of-the-year games. >+----- > >I read somewhere, in a technical article, that DVDs main asset in it's >storage capacity was not data compression but a laser that had a much >more focussed beam and that the laser light was at a different wavelength >than the regular laser companies now use for scanning CDs. > >

I believe the spec also allows for a bi-layer format. The laser can refocus through the upper (relatively translucent) layer and read the layer below. Hence a further doubling of data density. 3

For those interested in the specs, there are several sites about the format listed at Yahoo: http://www.accent.net/m_mario/dvd.htm http://e-town.myriadagency.com/html/dvd_html/index.html http://www.sel.sony.com/SEL/consumer/dvd/index.html There's also the Usenet group alt.video.dvd for further discussion. C. -- cspot@hyperreal.com (Chris.Hilker)

Zenon said: :I believe the spec also allows for a bi-layer format... Anyone interested in the mind-numbingly exciting details of laser-pit sizes and dual substrates can experience technological tent piching at: http://www.philips.com/pkm/laseroptics/dvd/brochure/advant.htm and http://www.dtvgroup.com/DigVideo/DVD/SonyDVD/feat.html bring on the 9-hour masterwerks (cough, wheeze) Who said prog-rock was dead? -d.w. who likes _pink flag_ and _computer world_ alot