🚀 go-pugleaf

In article <NEWTNews.18021.810769274.ralphp@prysm.unicomp.net>,
 <ralphp@ns1.unicomp.net> wrote:
>
>In article <42r823$g62@horus.infinet.com>, <georges@cdarchive.com> writes:
>> >A 4x CD and a 1x CD are exactly the same thing -- a CD. There is no
>> such
>> >thing as a 4x CD.  It's like saying there's a 4 minute Big Mac and a
>> 1
>> >minute Big Mac.
>> >Depends on how fast you eat 'em.
>(stuff deleted) 
>> Georges Brown
>
>	Of course, if I was to optimize my data that's put ON the CD to
>match a 4x CDROM player, that's a different story, right? <B-) After
>all, the main reason why some titles don't play any different on a 1x
>than they do on a 4x is that the data structures ON THE DISK (and well
>within the CD standard) is laid out to maximize performance on a 1x
>CDROM drive.

It's not really that complicated.

Computer systems vary a lot, what with hardware and software CD-ROM
caches and different I/O interfaces, so trying to optimize a CD-ROM for
a specific disc speed doesn't really buy you anything.

You could certainly take advantage of a 4X drive by putting better
quality video and/or audio on the CD.  Video compressed for a 4X
drive can contain 600KB/sec worth of data, while video compressed
for a 1X drive can only contain 150KB/sec worth, which is why it
won't look any better when read from a 4X drive.  With audio, you
can't get CD-quality stereo audio from a 1X CD-ROM, so you need
at least 2X to get that (or you can put it in an audio track instead).

But, I wouldn't say that the "data structures" are "laid out to
maximize performance" on a 1X drive.  You can't know what the seek
time will be in advance, nor can you know how the data will be cached,
so you can't really program in rotational information.  The best you
can do is to think "I'm going to get data at X KB/sec", and set up
your software to handle that.

On the issue of 4X vs. 1X CD-R, there are people in the CD-R media
industry who say there is a difference in media that is "certified" for
4X (or 6X).  I have yet to see any tangible difference between them - we
burn 10-30 discs per week of our products during a product development
cycles, and change media brands on a weekly basis (whatever's in stock),
and have had no problems.  We have both 1X and 4X JVC CD-R systems.
-- 
David Elliott - dce@netcom.com - http://www.btw.com/dce/