[7558037]

Power Calibration Tests:

Run on Blank/Unfinalized DVDs EVERY TIME THEY'RE LOADED!


Blank DVDs have a Power Calibration Area (PCA) near the inner hub for performing a 15-step test to determine the optimum power for writing to the DVD. A DVD-R can hold up to 7,088 separate calibrations.


These tests are performed each time you insert an unfinalized/blank disc and at various times as the burn progresses, and it stores the cumulative results of the power tests in a Recording Management Area (RMA).

A good explanation of PCA and RMA is here.

Cleaning Your Burner's DVD Gripper


If your burner's spindle/gripper surface (rubber or silcone) get dirty and/or greasy over time, it will not be able to grip the disc securely, which is an absolute necessity for this Performance Calibration test series. With a slipping disc, these tests will tell the OS that this disc is "unreadable" or "can't be recorded on" or similar message.


Since a DVD drive also changes speed when reading from inner hub to outer edge, a slipping gripper could allow the disc to slip at the speed-change point, which might show up as "unrecordable" or "unplayable" at that point.


If you operate your burner in a smoky/dusty room and/or handle discs with the center hub, the dirt and grease from your finger can be deposited and accumulate on the gripper over time.


You might be able to remove the top cover on your DVDR and see if your burner is open, like in the Philips 3575/3576 or Magnavox 2160, you might be able to clean the gripper with a Q-tip lightly moistened with alcohol. Some burner also have a top cover that might have to be removed before the gripper becomes accessible.



P. S. I got on this latest "kick" cuz I was intrigued by the following in the Troubleshooting section of my Philips 3575 manual:


"Recording Error - You cannot record on this disc as Power Calibration Area is full.


• When recordings are performed repeatedly onto an unstable disc, this area may come up to be full.


• Every time you insert a disc for recording, the disc’s working area will be taken up. And if you repeat this frequently, it will be used up sooner and you may not be able to record full 49 titles."

 

[crabboy]



Quote:
Originally Posted by wabjxo /forum/post/12049504

ONE MORE THING TO KNOW ABOUT BLANK DVDs I LEARNED TODAY:


Blank DVDs have a Power Calibration Area (PCA) near the inner hub for performing a 15-step test to determine the optimum power for writing to the DVD. A DVD-R can hold up to 7,088 separate calibrations.


Also, each time you insert a disc, it stores results of the power test in a Recording Management Area (RMA). This storage is cumulative.

A good explanation of PCA and RMA is here.


The only thing I would have liked to find is if the PCA and RMA are zeroed out on -RW/+RW-RAM discs by an "Erase" or "Format" operation?



P. S. I got on this latest "kick" cuz I was intrigued by the following in the Troubleshooting section of my Philips 3575 manual:


"Recording Error - You cannot record on this disc as Power Calibration Area is full.


When recordings are performed repeatedly onto an unstable disc, this area may come up to be full.


Every time you insert a disc for recording, the disc's working area will be taken up. And if you repeat this frequently, it will be used up sooner and you may not be able to record full 49 titles."

Are they trying to send people back to VCRs?

 

[Roger Lococco]

I doubt if anyone would insert an unfinalized disc so many times that the RMA area would be all used up.

Now what I'm wondering is if the calibrations are done every time the recorder powers up with a dvd already inside, sometimes I leave an unfinalized partially recorded dvd in for days.

 

[7558037]

Since a disc left in a unit loads each time the unit is turned on, it probably does the power calibration tests each time. I guess the worst case is you're giving the disc multiple chances to screw up somehow, e.g., hit a tiny bad spot in the PCA area and return an error???


I'm wondering how "they" can say a -RAM disc can be written to 100,000 (or even 10,000) times unless the rewriteables are different and zero out the PCA and RMA areas with an Erase or Format!?

 

[7558037]



Quote:
Originally Posted by wabjxo /forum/post/12049504


The only thing I would have liked to find is if the PCA and RMA are zeroed out on -RW/+RW-RAM discs by an "Erase" or "Format" operation?

Found one "tantalizing" tidbit in a TKEemporium.com Glossary that might begin to answer my question. It's on CDs but says the PCA area is "deleted" which makes it rewriteable 1000 times...some odd wording, but here it is:


"Power calibration area


Each CD-R and CD-RW at the beginning has got a so-called Power calibration area, in which the CD Writer can determine the laser power necessary to burn. Unfortunately this does not mean that every CD Writer can write on every CD-R. For most CD Writer there are makes of CD-Rs which cause problems. Often an update of the firmware can help. But then again a firmware update can make it impossible to write on some makes of CD-R.


A CD-R or CD-RW can be tested up to 99 times. This means that a CD-RW can not be written on more than 99 times. When deleting a CD-RW the Power calibration area also deleted so that a CD-RW can be written on up to approx. 1000 times. The UDF standard says that files which are changed can be written on a different place. This means tha if a file is changed often, that the CD-RW is not written on again and again in the same place but the whole CD is written on evenly (or as a general rule the resepective free area on the CD). It is possible that not all Packet Writing Programs use this method."

 

[vferrari]

This may explain why some people's unfinalized DVD+/-R discs become unreadable after repeated viewings/initializations. This has been reported on this forum from time to time. Finally, a good technical explanation that holds some water. Good info wabjxo.

 

[Roger Lococco]

according to the cdfreaks ''why dvd+r(w) is superior to dvd-r(w)" article, +r discs give better information to the burner, and has more calibration sectors to work with, 32768 sectors vs 7088.


Also a DVD+R(W) disc allows a drive to achieve better writing quality (independently of media quality), because it gives more information to a drive than a DVD-R(W). Indeed, just like with CD-R(W), the best writing settings for a given disc are found at startup during the OPC (Optimum Power Control) algorithm, which use data contained in the pre-pits blocks/ADIP words. And regarding OPC, a DVD+R(W) gives not only more information (e.g. power dependency on wavelength) but also more precise ones (e.g. startup laser power). Moreover, all these information are available for 4 different speed ranges (primary and upper speeds, normal and 4x+ mode), while - format only provides one set of data. This is very important because optimal writing settings are very sensitive to burning speeds. Also the OPC test area of DVD+ is 32768 sectors in total, compared to 7088 sectors for DVD-.

 

[Sasquatch7]

@wabjxo

Great find...thanks.

 

[UnknownVT]



Quote:
Originally Posted by wabjxo /forum/post/12049504


Blank DVDs have a Power Calibration Area (PCA) near the inner hub for performing a 15-step test to determine the optimum power for writing to the DVD. A DVD-R can hold up to 7,088 separate calibrations.

Can someone please clarify if that is

7,088x calibrations (which consists of 15-steps) -

or 7,088/15 calibrations?

Quote:
Originally Posted by vferrari /forum/post/12053767


This may explain why some people's unfinalized DVD+/-R discs become unreadable after repeated viewings/initializations. This has been reported on this forum from time to time.

7,088 viewing/initializations is quite a lot -

allowing for say 6 times a day -

that is still every single day for 1181 days

= about 3 years 3 months.


This is of course dependent on my question above -

is each of the 15-steps counted as one calibration -

or is one cailbration the full 15-steps?


If each step is counted as a calibration then (obviously) all the figures are 1/15th the above -

so every single day for about 79 days or 2 months 18 days

that's still quite a lot for a single DVD-R/-RW to spend in a DVD recorder

(and don't forget we are viewing/initializing it 6 times a day everyday....)

 

[7558037]



Quote:
Originally Posted by UnknownVT /forum/post/12057306


Can someone please clarify if that is

7,088x calibrations (which consists of 15-steps) -

or 7,088/15 calibrations?


7,088 viewing/initializations is quite a lot -

allowing for say 6 times a day -

that is still every single day for 1181 days

= about 3 years 3 months.


This is of course dependent on my question above -

is each of the 15-steps counted as one calibration -

or is one cailbration the full 15-steps?


If each step is counted as a calibration then (obviously) all the figures are 1/15th the above -

so every single day for about 79 days or 2 months 18 days

that's still quite a lot for a single DVD-R/-RW to spend in a DVD recorder

(and don't forget we are viewing/initializing it 6 times a day everyday....)

I'm just guessing, but the words suggest 7,088 separate power calibrations, each consisting of 15 tests?


But, as I said above:

"Since a disc left in a unit loads each time the unit is turned on, it probably does the power calibration tests each time. I guess the worst case is you're giving the disc multiple chances to screw up somehow, e.g., hit a tiny bad spot in the PCA area and return an error???"


And, I should add, as a disc ages ("fades"), especially one that is unstable from the manufacturer (Memorex et al?), eventually the law of averages *will* catch up and report that "this disc cannot be recorded"???


From everything I've read, an "unstable" disc (poorly made, aged badly, etc.) is one that might fail the OPC and will become unrecordable from the get-go if it fails the power calibration test.


By the way, I've since read that the OPC is repeated while the disc is recording...don't remember how often or when. I might try to find that ref. again but not sure how important it is.


Found one ref. to "Active OPC" in a DVD-Recordable.org article discussing a Nero disc check that shows dips at different spots of the graph:


"Some of the graphs have a number of dips in them and this is where the Active OPC (Active Optimized Power Control) kicks in. Active OPC monitors writing power and reflection of the media in use, calculating the optimum laser power and adjusting it in real-time. Which should in theory result in better quality burning."


Not sure if Active OPC is hardware or FW based.


For DVD-R/+R, might be a good idea to power calibrate and get the heck out of dodge...record immediately, finalize and put in good storage somewhere????

P.S. I did a Google search for "DVD OPC" and it returned 1,170,000 entries. I've seen "Immediate OPC," "Walking OPC," and "Running OPC" in just the first two pages of the search results!

 

[UnknownVT]



Quote:
Originally Posted by wabjxo /forum/post/12057536


I'm just guessing, but the words suggest 7,088 separate power calibrations, each consisting of 15 tests?

From everything I've read, an "unstable" disc (poorly made, aged badly, etc.) is one that might fail the OPC and will become unrecordable from the get-go if it fails the power calibration test.

Thanks for that -


But an unstable disc is likely to fail - in all sorts of areas -

including the OPC, of course -

however, it is nice to know about this area (as another part of potential failure).


I also wonder if re-formatting a DVD-/+RW would clear up this area and allow the disc a "fresh" start as if it were -

or is the 7,088 calibrations the life of a disc

(32,768 in the case of a DVD+RW)?

 

[7558037]



Quote:
Originally Posted by UnknownVT /forum/post/12057750


Thanks for that -


But an unstable disc is likely to fail - in all sorts of areas -

including the OPC, of course -

however, it is nice to know about this area (as another part of potential failure).


I also wonder if re-formatting a DVD-/+RW would clear up this area and allow the disc a "fresh" start as if it were -

or is the 7,088 calibrations the life of a disc

(32,768 in the case of a DVD+RW)?

My Post #5 describes just one ref. I found that suggests the OPC/RMA area in a -RW/+RW (prob. -RAM also) gets wiped out by a Format, which the article oddly calls "Delete."

 

[7558037]



Quote:
Originally Posted by wabjxo /forum/post/12057536


By the way, I've since read that the OPC is repeated while the disc is recording...don't remember how often or when. I might try to find that ref. again but not sure how important it is.


Found one ref. to "Active OPC" in a DVD-Recordable.org article discussing a Nero disc check that shows dips at different spots of the graph:


"Some of the graphs have a number of dips in them and this is where the Active OPC (Active Optimized Power Control) kicks in. Active OPC monitors writing power and reflection of the media in use, calculating the optimum laser power and adjusting it in real-time. Which should in theory result in better quality burning."


Not sure if Active OPC is hardware or FW based.

Found my answers in the article linked in Post#1:


On whether OPC is hdwe or FW based... it's FW:

"This whole process is controlled by the recorder, and is initiated by programs such as Nero or other disc writing applications." Our DVDRs may have an initial PC in its FW, but may not (?) have Running OPC as described in the next para. since it's FW-based...might depend in the recorder mfgr?


On OPC running while recording...YES:

"The DVD specification also recommends the use of Running Optimum Power Control (Running OPC) to help ensure that the proper recording power is used across the entire disc. Running OPC's ability to deal with variations in hardware and media (as well as dust, scratches, and fingerprints on discs) plays a critical role in ensuring data integrity. If you receive a "Power calibration error" error message the cause will be either poor media, poor power, or a defective recorder."


I don't think DVDR users will receive any "Power calibration error message" as noted in the quote above...most all I've read on receiving this error notation is with external burners or those in computers, and many-many with using Nero. We'll probably just see a "Can't Record" or "No Disc" type error...OR it could stop recording cuz the Running OPC found a defect???

 

[JeffWld]



Quote:
Originally Posted by vferrari /forum/post/12053767


This may explain why some people's unfinalized DVD+/-R discs become unreadable after repeated viewings/initializations. This has been reported on this forum from time to time. Finally, a good technical explanation that holds some water. Good info wabjxo.

I agree that it's good to have a more detailed explanation of this issue. I remember first seeing a reference to it in the manual for my first DVD Recorder (the original Panasonic E-20 from 2001). It was a rather cryptic statement that simply indicated that multiple insertions of an unfinalized DVD-R could render the disc unuseable. Shortly after I got the recorder, I researched more technical detail on the subject.

 

[Vamp9190]



Quote:
Originally Posted by Roger Lococco /forum/post/12056230


according to the cdfreaks ''why dvd+r(w) is superior to dvd-r(w)" article, +r discs give better information to the burner, and has more calibration sectors to work with, 32768 sectors vs 7088.

I have always used +R in my PC and now recorder. Never once messed with -


Glad to have tech data to back-up (no pun intended) my preference.

 

[7558037]

Hey, I just realized that, if a power calibration has to write the date/time of the calibration, that may dovetail into why the DST Bug makes DVD ops run very slowly or freeze up!?


It's trying to decipher what time it really is based on the NEW DST rules in the signal or uploaded to an STB, or on the OLD DST rules embedded in the recorder's FW?


In thinking of how many recorder ops rely on or use a date/time makes me dizzy, and I'm sure there are some not really obvious, like power calibration tests?


Here's a quote from mscience.com on DVD-RW that uses the word "updated" which *might* suggest the data has to have an identifier so it know what to update...could be a date/time or maybe a number ID or ....? It also seems to suggest a -RW disc is just "updated" and maybe not zeroed out???


"DVD-RW Defect Management


DVD-RW drives flag but do not replace defective sectors. The R-Information zone that precedes lead-in contains a Recording Management Area consisting of a Power Calibration Area followed by a Defect Status Bitmap. Every ECC block is represented in the bitmap that results from optional certification by the manufacturer or is optionally updated when the disc is reformatted. DVD-RW is designed for sequential recording, such as streaming A/V. Although conventional DVD-Video players cannot access the Defect Status Bitmap, many A/V applications are not sensitive to defective sectors. Because drive-based defect replacement is not available, DVD-RW discs may not be suitable for computer data storage. Software-based defect management could be provided by UDF."


HEY, THE PHILIPS 3575 (AND MAGGIE?) FILE SYSTEM IS SUPPOSED TO BE "UDF"...COOL!

 

[7558037]

More grist for the DVD mill!

I just learned that DVD+R are GOOD and DVD-R are EVIL!

Check this article which refers to this article as its source.


I looked at a DVD+R and DVD-R under mag. glass and there is an "extra" ring that looks semi-burned near the hub of the DVD-R, plus an ID number.


An interesting thing in the 2nd link is the German magazine test of DVD-R and DVD+R compatibility across various players:

Aug 6, 2006

DVD-R 95%

DVD+R 93%, but with "bit change to DVD-ROM, 95%."

 

[wristpad2]

I've got a problem with DVD+RW that I record on my Philips 3507 (Verbatim 2.4x and Maxell 4x discs). According to the manual, +RW's do not finalize unlike the -RW. I made some edits (changed the thumbnail) and I notice that the "Make Edits Compatible" is grayed out. I think the "Edits Compatible" is only for editing chapters though.


I decided to keep the +RW recording that I made so I transferred the disc to my PC so that I could then re-burn it to a DVD +R. I tried to use DVD Shrink to burn it. However, Shrink would not recognize the contents on my hard drive. I get a "Invalid DVD navigation structure" message. Anyone figure out how to copy a DVD+RW that has been recorded on a DVD recorder?


Also, since the +RW is not finalized, won't the initial power up calibration load up on the disc and make it unusable eventually?

 

[7558037]

+R/RW discs have MANY more calibration sectors than -R/RW so it unlikely you'll fill up the PCA. For going to your computer, try finalizing the +RW?

 

[UnknownVT]



Quote:
Originally Posted by wristpad2 /forum/post/12575830


I decided to keep the +RW recording that I made so I transferred the disc to my PC so that I could then re-burn it to a DVD +R. I tried to use DVD Shrink to burn it. However, Shrink would not recognize the contents on my hard drive. I get a "Invalid DVD navigation structure" message. Anyone figure out how to copy a DVD+RW that has been recorded on a DVD recorder?

I have that exact same situation on DVD+RW recordings made on my cheapo SV2000 WV10D6 DVD Recorder from WalMart


I eventually figured out that this occurs when there are multiple titles/programs recorded on the +RW -

and when using the "Full Disc" method on DVDshrink.


However if I do a ReAuthor - DVDshrink reads the +RW fine - and I can find the titles I want to backUp - and everything proceeds just the way I expect.


Most of the time I just record just one title/program on a +RW - edit that to top/tail and hide ads - and make edits compatible - then go to my PC to DVDshrink backUp and burn to a +R.


I have just one 25-pack of DVD+RW that I use for recording - which is plenty - as I re-cycle those by erasing/formatting on the DVD recorder.


Hope that helps.