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I've read about the new 650 meg md's coming out, but I've also read that
they will only be data MDs. I'm pretty sure that this is not the most
current news, so can anybody enlighten me as to the current situation
for 650 meg md's?
Will they be for audio also? I really hope so, it can only be good for
Minidisc...74 minutes of uncompressed music (to give it a more status as
a robust recording medium) or almost 6 hours of compressed music!!!!
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If an "extended density" audio MiniDisc is to be released, there are a lot
of issues to be discussed and truths have to be realized. For example, the
format will need to be promoted under a logo which embodies the MiniDisc
logo. This logo cauld be referred to as an ED MiniDisc logo, and discs and
hardware that work to the specifications would have to have this logo.
An assurance of backward compatibility would have to be guaranteed in the
form of players being able to play either standard MiniDiscs or ED MiniDiscs
in all recording modes; and recorders being able to record in the standard
modes when a standard disc is mounted as well as the ED modes when an ED
disc is mounted.
A recorder; such as a low-end portable, boombox, low-end stereo, or low-end
MiniDisc component deck can be able to be "quasi-compatible" by being able
to play the ED discs recorded in all ED modes but only able to record on
standard MiniDiscs. This could be a cost-effective way of bringing ED
MiniDisc into lower-price equipment.
The recording modes allowed would have to support 74 minutes of stereo
linear PCM audio, 148 minutes of mono linear PCM audio, approx 296 minutes
(nearly 5 hours) of stereo ATRAC-compressed audio, or 592 minutes (nearly 10
hours) of mono ATRAC-compressed audio.
By using these various modes, it allows for an existing stereo MiniDisc
design to be modified for playback or recording of these formats. Signal
routing can be performed based on the recording mode -- go via the ATRAC
codec or go straight to the SP-DIF outputs and analogue-digital conversion
department.
As for buffering, this can be achieved on PCM nowadays as the cost of memory
silicon is reduced -- as we know through the use of buffering on portable CD
players.
Control logic is just about the same except for more positions on the
recording mode switch; and some extra "behind the scenes" logic to cope with
the recording modes and the extended-density MiniDiscs.
The only major change required would be the transport which would have to be
designed for narrower resolution and also to be able to detect and react to
the difference between the two types of discs.
So theoretically, it would mean that there is very little need for major
chassis revision to occur when implementing an extended-density MiniDisc.
Support for these discs at various levels would be considered a "product
differentiatior" feature for different MiniDisc units, thus allowing a
manufacturer to have a large line-up of models at varying price ranges.
With regards,
Simon Mackay
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