3500 LD/TDB Z-CLV vs. CAV at 12x

vbimport

#1

Hi!

Summary: With 2.TD, the 12x burns are slower than with 2C8, due to change from Z-CLV to CAV.

Until recently, I used TDB 2C8 firmware on my ND-3500 because it burned my TDK002 better than LD-firmware. Having burnt my last TDK002, and expecting YUDEN000T02 and MCC03RG20 to arrive this week, I flashed to LD 2.TD. I had some RICOHJPNR02 left which had served me well with the 2C8 and I decided to burn one with 2.TD @ 12x. I was very surprised to see that 2.TD burns @ 12x with CAV, whereas 2C8 burnt 12x with Z-CLV.

First pic RICOHJPNR02 @ 12x with 2C8, second pic RICOHJPNR02 @ 12 with 2.TD (dunno why I got thise strange colours with CDSpeed 4.01):

The Z-CLV was faster than the CAV-burn, with 2C8 my 12x burns were sub-7 mins and with 2.TD it took almost 7:30. If you look closer at the burns, you can see that the Z-CAV burn is faster than the CAV burn. It switches to 8x already at 0.5gb whereas the CAV burn reaches 8x at 1gb. The Z-CAV burn hits 12x at 2.4gb whereas the CAV burn hits 12x at 3.5gb.

Liggy and Dee, were you aware of this change in the 12x burning strategy, and if you were, is that something that you have implemented, and if so, why? Do you think it is possible to change back the 12x to Z-CAV as Z-CAV @ 12x actually seems faster than CAV?

Finally, lets compare the 2.TD 12x CAV burn with a 2.TD 16x CAV burn:

As you can see, the 16x CAV-burn starts off much faster than the 12x CAV burn, and the speed increase is also more agressive. The 16x CAV burn hits 12x already at 2gb, compared to the 12x CAV burn at 3.5gb and the 12x Z-CLV @ 2.4gb.

If we could get the 12x CAV burn to start out exactly as the 16x CAV burn hitting 12x at 2.0gb and then maintaining 12x for the rest of the burn, that would be a winner. If not, I prefer the Z-CLV method on the 12x burns.

Thx for you patience, rather long post :o


#2

The drive is using 13x CAV if you select 12x write speed on discs that could be written at 16x, so if your manipulated firmware increases max write speed for Ricohjpn-r02-03 from 12x to 16x, this is the result :slight_smile:


#3

We can set a “flag” in the firmware to force a 12x Z-CLV burn when using a 16x strategy group, but generally 13x CAV burns the disc with better quality, all be it a little slower.


#4

@alexnoe:
Thank you for pointing this out, I didn’t know.

@Dee:
I know you know what you talk about so I take your word on that one, so that brings me back to:

I mean, if it uses 13x CAV, then it should start out like a 16x CAV right? Or at least it should be possible to fix?


#5

Both burns are CAV, so endspeed/startspeed is Constant, identical on both burns.


#6

@ala42
If you look at the pictures in the first post comparing the 12x CAV and the 16x CAV, you will see that the disc rotates faster throughout the 16x burn. At the 12x burn, the disc rotates at about 7000rpm, the 16x burn, at 10000rpm.

What I was trying to suggest was that it would be nice to have the 12x as P-CAV, the disc rotates as fast as it does at the 16x burn at first, and then around 2gb, when it hits 12x, it maintains 12x for the rest of the burn.


#7

riiiight but what alan is saying is that if it started at 10K it would finish @ 10k and be a 16x burn. CAV means constant. it can’t start at 10k (16x start) and slow to 7k by the end of the burn (12x end)

in rereading your second para my response is: this drive does not use p-cav for anything it writes

from the mad dog/3500 review: Please note that the MD-16XDVD9 uses a Z-CLV (Zone-Constant Linear Velocity) write method when burning DVD±R at 12X, 8X, and 6X speeds and CLV (Constant Linear Velocity) for 16X DVD±R writing.


#8

The NEC 35xx series drives all use CAV (Constant Angular Velocity) for 16X burns, meaning the drive rotates at the same speed throughout the burn. As the pickup head moves from the center to the outer edge of the disc, the disc surface is moving past the pickup head ever faster. (starts around 6x finishes 16x)

So if a burn is to end at 13X it must start slower as the same CAV (Constant Angular Velocity) method of burning is used.
To have a PCAV (Partial Constant Angular Velocity) burn strategy. NEC would probably have to completely rewrite the strategies.


#9

A little nitpicking: The NEC 3500 uses P-CAV for many CD-R burns.

If you don’t believe me I have the Nero CD-DVD Speed screenshots to prove it :flower:


#10

ummm drage that would be because your discs are not 48x rated OR their max burn speed in an NEC is not 48x. again from the review

We can see that the MD-16XDVD9 uses CAV (Constant Angular Velocity) to write at its’ rated CD-R speed of 48x. This gives an average speed of 36.38x.


#11

We can see that the MD-16XDVD9 uses CAV (Constant Angular Velocity) to write at its’ rated CD-R speed of 48x. This gives an average speed of 36.38x.
As you can easily see, the drive reaches 48x at about 75 minutes and then switches to CLV. So it does use P-CAV, even though Nero CD DVD Speed is too stupid to realize this.

Although I don’t have a NEC 3500A for testing here, i’m pretty sure it did the same last time I tried



#12

Here from a 3500A.



#13

rotation speed is staying the same so i don’t know if i call that pcav.


#14

That is a matter of how you define ‘same’ :). The rotation speed display resolution is not sufficient to prove that it realy drops, but the constant write speed proves it.


#15

whatever… if you think that makes it PCAV then rave on.

here are some PCAV examples that you could use this as a reference in the future. in each case there is a noticeable decline in spining which is what the OP of this thread was asking for… for the drive to start @10k and end @7… which it doesn’t do in the cd portion of this discussion. in fact it really doesn’t appear to even drop by 100 rpm let alone 3k




#16

the definitions roll in:
http://www.answers.com/topic/cav-1
“Partial CAV” (P-CAV), also known as “CAV/CLV,” breaks the disk into two zones. Used in certain CD-ROM and DVD drives, P-CAV keeps the speed constant for the inner zone (CAV), but varies the disk rotation for the outer zone (CLV).

plextor
“Partial CAV” (P-CAV), also known as “CAV/CLV,” breaks the disk into two zones. Used in certain CD-ROM and DVD drives, P-CAV keeps the speed constant for the inner zone (CAV), but varies the disk rotation for the outer zone (CLV).
http://www.plextor.pl/pdf/PlextorPCAV.pdf

sorry but i do not see 2 “zones” and i don’t think 75 minutes would be considered an inner zone in any event.

time to ask the man


#17

Here’s a couple of Nero CD-DVD Speed Write Transfer tests (simulations) performed at 32x and 40x on 48x capable media.

The writing method is clearly P-CAV.

…unless of course you can come up with a very creative definition of P-CAV such as “it doesn’t count because the drive could write the disc faster if it wanted to”?!

I don’t write all my media at maximum speed because maximum speed rarely provides the best quality.




#18

i have been overruled. the bollrog says it is PCAV…