Return to EQ index

All information in these pages is copyright (c) 1989-2003 by Roger Nichols. All rights reserved. Permission for personal reference only, and may not be reproduced by any method without written permission.

I Want My DVD
by Roger Nichols

Actually, I also want my CD-R, CD-RW, CD-ROM, DVD+RW, DVD-R, DVD-RAM, CD-RW, DVD-ROM, DVD-A, DSSD and FEM. Wasn’t it much easier when there was just 33 1/3-rpm, 45-rpm discs and cassettes? I even had a turntable that mounted under the dash so you could play records in your car. I used to make compilations of my favorite songs by copying them to my Rek-O-Kut portable disc cutter, in 1960! But I digress.

DVD+RW.

The DVD+RW Alliance consists of Dell, HP, Mitsubishi Chemical/Verbatim, Philips, Ricoh, Sony, Thomson and Yamaha. Some of these companies have started shipping re-recordable DVD+RW drives. The first version of the drives does not record DVD-R, but only DVD+RW. The next generation of drives will support DVD-R although current drives will not be upgradeable. A DVD+RW disc is compatible with DVD-ROM drives and standard DVD players.

What makes DVD+RW different is that you can record video directly to the drive without authoring first, just like your trusty VHS machine recorded whatever you shoved into it. You can also punch into previously recorded video. This is made possible by the zero gap recording process used in DVD+RW. After you have re-recorded one minute in the middle of a two-hour disc, it will play back without a glitch on your video DVD player. As for current DVD-R/RW discs, the DVD player will not play past the first insert. As far as the player is concerned, the disc is corrupt and nothing can be accessed past the edit.

The drives will record on CD-R and CD-RW, which means you only need one drive for all of your burning desires. Oh, by the way. HP has announced that it will discontinue the manufacture of CD-R/RW drives. With prices down to $79 for some CD-R/RW drives it is time to move on to the next level. Backwards compatibility with CD-R/RW makes the transition easier, but $500 for a drive is a big jump for some. Just remember that one year ago DVD-R drives were $2,000 to $5,000. Maybe I will wait until they come down to $79.

CD-R/RW Leftovers

Well, I still went out and bought a couple of CD-R/RW drives. Plextor is shipping their new 40x write machine. I tried it out, and a full 80minute CD-R burned in 1:52. Yup, that is less than two minutes to burn 80 minutes of music.

The new 40x drive uses what is known as Z-CLV, or Zone-Constant Linear Velocity. Constant Linear Velocity means that the same length of groove goes by the laser whether you are reading the inner part of the CD or the outer part. That is why you see the CD slow down as the music plays. The speed changes from 500rpm to 200rpm, but the groove passes under the laser at a constant 1.2 meters/second. If you recorded the entire disc at 40x the disc would be turning 20,000rpm at the inner diameter, slowing to 8,000rpm at the outer edge. At 20,000rpm someone could get hurt!

Now, if we spin the disc at 8,000rpm, the write speed at the center would be 16x normal. As we get a little farther along, the groove is going past at 24x, and then 32x, and finally at 40x. These are the Zones in the Z-CLV system.
Remember that most CDs burned only contain 350 Megabytes, so you will never get into the 32x or 40x Zone. But if you are like me, you have to have one anyway.

Yamaha has another card up their sleeve with their Lightspeed 3, 24x drives. They have a new slant on CD burning called “Audio Master.” Actually write the disc at 1.4 meters/second instead of 1.2 meters/second. This means that you can only get 63 minutes of audio on a 74-minute disc, but the pits and lands that make up the data are slightly longer. This is still within the Red Book specification of plus/minus 10%.

Yamaha says that this system reduces jitter and produces better sounding CD-Rs. I burned one today and listened back, but it sounded the same as the normal speed disc. I will have to do more checking on this one. Oh, the disc plays back at the same speed as it was recorded. The pits whiz by at the same number of pits per second, the pits are just longer so the disc spins faster. It all works out.

High Speed Burn Errors

Since we are talking about fast CD burners, what about the error rate at higher speeds? Well, it used to be that 2x was the best speed to burn at for low error rates. If you went any higher, you were producing an inferior product. As the disc turned faster the LASER was on for a shorter time to burn the pit because the pit went by faster. The pit geometry suffered and the error rate went up. This is no longer true.
The latest generation of CD-R recorders contain variable power LASERs and therefore pump the same quanta of energy into the pit at all speeds. If the LASER is on for a shorter period of time, then the power is boosted to make sure that the correct amount of energy was used to insure the proper formation of the pit.

After error checking 17 different brands of media on 7 different drives at all speeds from 1x to 40x, none of the drives produced more errors at higher speeds, and most of them produced lower error rates at the higher speeds. Mitsui silver discs showed the lowest overall error rate at all speeds. So, as long as you use media labeled for use at the proper speed, go for it. Charge the client for an hour per disc and burn them in less than three minutes each. That is what I call profit!

Copy Protection Again.

Some labels are using a new copy protection scheme on CDs. It turns out that the copy protected CDs won’t play back on all CD players. They won’t play at all on a Mac, DVD player, or game console. The audio cannot be ripped by a CD-ROM drive, but it also might not play in your car. The record company has agreed to accept returns from irate customers, but most retail CD stores won’t let you return a CD once it has been opened.

I think the way they do it is by pressing the CD with errors imbedded in the audio data. The player will mask the data by substituting the previous good sample. This means that the actual audio will not be exactly the same as what was mixed in the studio, but no one will notice except the artist, so who cares. These errors will be copied when the disk is ripped, and saved on the copy as valid data, but it won’t be valid audio. These errors will play back as distortion, frying, hissing and clicking on the copy.

What these record companies don’t get is that if you can hear it play back on any player, you can copy it. Even if you copy from the analog outputs of your CD player it will still sound ten times better than the MP3 it will be turned into before it hits the web. All they have succeeded in doing is preventing lots of people from buying the CD because they can’t play it back on their CD players. So they will buy the bootleg version that will play back on anything.

Keep in mind that the Red Book standard has no provisions for copy protection, and therefore any copy protection method makes the disc non Red Book compliant. Sony/Philips could actually pull the license of the plant pressing these copy protected CDs. I guess that would be the ultimate copy protection. Don’t press any CDs and they can’t be copied!

Hang on; let me call my patent attorney, I think I could be on to something. I’ll get to the DVD-A, DSSD, and FEM next month.