Rings on reflective side of DVD media

vbimport

#1

Greetings, I have a question regarding the DVDs I burn. When I started checking the disks I noticed that some of them have rings on the reflective side. The rings are only noticeable if I use some heavy light on them like a camera flash. Check the following photo:

The ring I am talking about is marked by a white arrow. It is very thin but not distinctive. From observing I noticed that the ring is like a seprator between a lighter (in color) and less lighter areas on the reflective surface. Is this what is referred to as jitter? I copied the DVDs back to the HDD and did byte by byte comparison and everything checked out without issues. Anyone has any information on this?

Regards.


#2

No, it’s not what is referred to as jitter.

The rings occur when drives recalibrate (the laser) during the burn process. Some drives do a more aggressive recalibration than others, and the change in intensity or strategy (maybe short bursts of high power, short bursts of low power, long bursts of high power, etc etc; a different focus, a different pulse width, and the like.) means a change in how one burned area looks in comparison to another.

Jitter is the measure of how well the pits and lands are formed, and isn’t directly visible to our eyes. Jitter may change at these recalibration points (the drive is modifying its behavior, after all), but it’s not a given.


#3

The media that sell in Brazil, the vast majority use fake media codes … is very common I see this kind of “ring” in my recordings … the poor people of the recorders are struggling to get a good recording and … is not that they can? :smiley:

I am seriously thinking of starting to buy only imported media, as I did with my Blu-rays … the media sold here are very bad …


#4

Albert, thanks a lot for the detailed explanation.

vdsacchi, Thanks. I noticed that using two different DVD brands makes a difference. I mean on the other brand I used, I noticed that the ring is less visible and the areas before and after the ring are almost the same color.

Should I worry about this happening? By the way, I forgot to mention that I do not have desktop PC. So, I am using my drive externally using an IDE/SATA USB Adapter. Will that make any difference? I am using a an ASUS DRW-24D3ST drive that I purchased 10 months ago. Also, I am using the 8x speed not 16x on the drive (Nero Express 8 Essentials) if that makes any difference.


#5

Should you worry? No, it’s normal for many drives at many speeds.

You’re using a rebadged LG drive, and LG drives are known (1) for doing drastic recalibrations due to their very…specific write strategies and (2) for sticking to these write strategies, consistently. Their newer drives seem to be a little less aggressive, but they can easily still produce rings.

On older LG drives, these recalibrations occurred every 2x or so, so on a 16x burn, hitting 8x - 10x - 12x - 14x each resulted in a chance for a new ring.

It might be similar here, though the newer LG drives (like the one your drive might be based on) do recalibration checks more often; you could see one ring until the drive reaches 8x, then another ring for the remainder of the burn at 8x, and there might be more smaller rings if the drive decides to readjust itself.

Every little dip on this graph is the drive making a decision, and is a chance for a new ring:

(your drive may be based on an NS95 instead of NSB0, but the graph would be similar)

Even with this, assuming the drive makes a good decision & assuming the media is OK, write quality is fine.

On mediocre or bad media (or media with very bad firmware support, or with a bad drive), the drive might have a greater chance to make rings because it has to figure out the best way to compensate for a problem it encounters. It might decide to make drastic changes at every single checkpoint (trying feebly to improve quality), rather than only once or twice.

Different disc models will respond differently to the drive’s changes, and the drive will decide differently depending on the disc model. So yes, it is normal for two different models of disc to have different ring patterns. :slight_smile:

(Note that different brands may use the same disc model, with the same OR different quality, and discs vary in quality anyway).


#6

Albert, thanks a lot for the information. One last question, though. Are all drives like this? Are their any better drives that make solid DVD discs without those rings and differentiation in color? Going back to my old DVD spindles, I noticed that some of the disks are 100% solid without any rings while others have one ring but with less noticeable color difference between the two areas before and after the rings.


#7

All drives now have the capacity to do this; they all recalibrate, and have done so for a long time.

Maybe LiteOn drives can be set to burn without recalibrating during the burn, but I believe they also force recalibration during the burn for some disc models.

For your drive (and most high speed desktop drives): if your drive supports 4x or 6x on your media (I’m not sure it does in this case), they write at a constant speed across the whole disc at that speed. That means that the drive might not recalibrate at any of the checkpoints (and there’s no change in the speed, so there’s no need to force a recalibration at a speed change). But even then it might still happen.


#8

I guess the only option I have is to get the best of brands and hope for the best. Thanks, Albert.