Film-Tech Forum ARCHIVE: 90 Minute CD-R's

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Topic: 90 Minute CD-R's

Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 05-07-2001 06:07 PM

I've heard that new 90 Minute CD-Rs exist, but they are not yet available in the USA. Has anyone else heard this? If so, would they be able to play on most normal CD players? Or would new CD players capable of playing these CDs need to be purchased?

Also, has anyone else noticed that 74 minute CDRs say they can hold only 650 megs, but 74 minutes of audio is actually about 750 megs? Same holds true with 80 minute CDRs...they claim to hold only 700 megs, but 80 minutes is slightly over 800 megs!

Must be a data vs audio thing.

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Evans A Criswell
Phenomenal Film Handler

Posts: 1579
From: Huntsville, AL, USA
Registered: Mar 2000

posted 05-07-2001 09:23 PM

My guess would be that the overhead of putting a file system on the disc (formatting information) would reduce the amount of storable data.

Let's see: 74 minutes times 60 seconds per minute times 44100 samples per seconds times 4 bytes per sample (stereo) gives a total of 783216000 bytes, or 746.9 megabytes. Interesting. I wonder if parity or redundancy in storing the information may be part of the reason as well? I'm curious about this. Using the above logic, 80 minutes is 846720000 bytes, or 807.5 megabytes. I'm also curious if the 74 minute and 80 minute nominal CD capacities are exact.

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Evans A Criswell
Huntsville-Decatur Movie Theatre Info Site

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Sean Weitzel
Jedi Master Film Handler

Posts: 619
From: Vacaville, CA (1790 miles west of Rockwall)
Registered: Dec 1999

posted 05-07-2001 09:38 PM

Haven't heard or researched the new 90 min discs, as for storage sizes, Evans is partly correct, in that in storing data on a CD-R, formatting takes up some of the available space. In addition, computer data must be very exact and very immune to surface defects on the CD media, thus, additional storage space is used as sort of an added redundancy to counter possible read errors due to defects. I believe this error correcting code is called reed-soloman.

Audio, does not need as much media based error correction as audio cd players have this error correcting ability built into the hardware.

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Jonathan Haglund
Film Handler

Posts: 81
From: Irvine, CA, USA
Registered: Apr 2001

posted 05-07-2001 11:57 PM

90 minute cd's are not an official spec, just like 150mhz ram. You can technically use the CD to 90 minutes using "overburn," a featre only found in certain burning software, but there could beproblems because the CD-R standard says the max is 79:59 min, and thus readers based on this standard may be unstable.
Titles able to do overburning include, but are not limited to:

Nero 5.0.3.8
CDRWIN 3.8C
WinOnCD 3.8 Power Edition
DiscJuggler 3.00.758
Feurio 1.52

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Jonathan Haglund
Edwards Theatre Circuit, Inc
Park Place 10

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Mike Blakesley
Film God

Posts: 12767
From: Forsyth, Montana
Registered: Jun 99

posted 05-08-2001 01:42 PM

I once made up an 80-minute CD, but then mistakenly burned it onto a 74-minute blank. I got about 78 minutes onto it.

I've been meaning to put together a 90-minute program and then see how much will ACTUALLY fit onto an 80-min. disk.

BTW I use Sonic Foundry CD Architect and a Yamaha CD burner, if anyone's wondering.

I'm sure that many players would choke on overburned disks.

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Jonathan Haglund
Film Handler

Posts: 81
From: Irvine, CA, USA
Registered: Apr 2001

posted 05-08-2001 07:48 PM

BTW, the only way to copy Playstation games is to use overburn.

Also, the difference between 74 and 80 minute discs is that the "tracks" are placed closer together. In a 90 minute, the tracks are a little closer, but most of the extended space comes from overburning.

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