Date   : Thu, 04 Jan 2001 10:54:52 +0000
From   : Paul Wheatley <p.r.wheatley@...>
Subject: Re: VFS: (BBC Video Disk) : Doomsday Project

Andrew Chesterton wrote:
> 
> I don't know if the doomsday disks use the same storage formats as normal
> Laserdisks, but if they do, you have a choice of two formats each with there
> own storage capacities.
> 
> The capacity depends on how many 'frames' are stored per track on the disk
> 
> Constant Linear Velocity (CLV) disks have the greatest capacity because the
> number of frames per track increases as you progress towards the edge of the
> disk. A film such as 'Armageddon' fits on a single disk when stored using
> this format. The problem is that 'freezing' a single frame does not give a
> very stable picture.
> 
> Constant Angular Velocity (CAV) disks have less capacty because the number
> of 'frames' stays constant accross all tracks. A film such as 'The Matrix'
> takes both sides of two disks when stored using this format. The plus point
> is that 'freezing' a single frame gives a perfect crystal clear picture.

The Domesday discs use the CAV standard. Most of the analogue data on the
disc are still pictures, so as you've pointed out freezing a single frame on
a CLV disc would not be suitable.

> 
> As for GB storage capacity I have know idea.

Not sure of the max amount of digital data that can be stored on 1 side, but
as I've said theres approximately 150 megs of digital data on each side on
the Domesday discs.

Paul