brwk@doc.ic.ac.uk (Bevis King) (01/18/89)
I thought I would post out what info I have on the CAA process in the
hope that if I'm wrong somebody will correct me, or that someone may
be able to add to what I know, so here goes:
CAA - CONSTANT ANGULAR ACCELERATION
As understand it, CAA mastering for CLV disks was first introduced
about two years ago to increase the running time of NTSC LV CLV disks
to almost exactly 1 hour per side. The intention being to reduce
the number of films that required a second disk to be used. This
apparently resulted in the new CAA-mastered disks being able to
hold 108,000 frames (with digital frame stores now becoming realistic
maybe CLV-disks can be used for frame stores where capacity is more
important than speed).
Interestingly, in the PAL environment, the introduction of CAA-mastering
opens the way for CLV disks to contain up to 72 minutes per side. There
have however been a number of problems with the CAA process, or more
specifically with the master recorder at PDO Blackburn (or so I understand)
which for a period produced disks which would not play on Pioneer PAL
players. Apparently, the same problems have been found to occur with
the new Philips CDV-475 PAL combi. I have recently tried to play a disk
which was known to be one of these faulty disks on my CDV-475 and I
found the following symptoms:
a) between minutes 54 and 57 on side 1 of the disk, a loud
"poping" became apparant on the audio track.
b) during minute 58 a number of "twists" affected the picture.
Thereafter, the side terminated.
I am also somewhat puzzled by the very presence of a new type of mastering
(ie CAA) and assume this meant that previous methods of CLV mastering
involved a step progression of some sort... does anyone know why this
was?
Regards, Bevis
Bevis King, Systems Programmer | Email: brwk@doc.ic.ac.uk
Dept of Computing, Imperial College | UUCP : ..!mcvax!ukc!icdoc!brwk
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