MAN - Doc #04 - OverBurn CD-R's

> L'OVERBURNING <

INTRODUZIONE
L'overburning è il sistema che permette di scrivere circa 30MB / 3min. in più sui CD vergini (se supportato dal masterizzatore).
Almost every CD-R can hold between 660 and 690 Mb DATA but usually the CD-R TotalSpace is physically set to 650 - 659 Mb. The extra space is normally used for the mandatory 90 seconds lead-out area. By shortening this lead-out area, extra DATA can be written to the CD-R. This methode of writting a CD-R is called OverSizing (or OverBurning).

SCRIVERE CD-R OVERSIZE
The reason that the TotalSpace of a CD-R is set to maximum 659 Mb is because most CD-Writers are not able to write more than this value to a CD-R (because of mechanical or firmware shortcomings). Thus bigger CD-R's are useless for these CD-Writers. Only a few CD-Writers can go beyond this 659 Mb boundary, the most common are mentioned below.
A CD-R is in fact recordable up to the end of the physical pre-groove which contain information so the recorder can position the laser for recording, normally somewhere in the 77 minutes.
To be able to OverSize CD-R's the Disc-At-Once (DAO) mode of the CD-Writer is utilized. DAO mode, instead of TAO, must provide it's own lead-out (which now can be moved to the very end of the CD-R).
Disc-at-Once has only been added/available with the recent generation of CD recorders and recent firmware upgrades. At the moment about 95% off all CD-Writers support DAO but not all of them support OverSizing!
In DAO mode the CD-R software sends a CUE Sheet (TOC) to the CD-Writer, this CUE Sheet holds information needed for the leadin area (tracksizes & more). A CD-Writer which is not able to OverSize will reject the CUE Sheet when it contains track information which ends past the blank media reported length. The length is read from the pre-groove of the blank media and specifies the last possible position where DATA can be safely written to. A CD-Writer which is able to OverSize will just ignore this length and will try to burn the blank media up to the end of the pre-groove.
Keep in mind that OverSizing is not totally without risk. OverSizing is writing DATA to a place which is outside the original CD-R specifications. This can result that some CD readers (Audio & Data) can have problems reading the last 90 seconds of an OverSized CD-R. There is no garantee that the quality of the pre-groove, dye and reflective layer, past the reported length, is as good as it is before!
A few CD-Writer software packages warn you that it is possible to damage your CD-Writer when trying to oversize a CD-R. At the moment there is totally no evidence supporting this warning. They just put it in their software just in case it happens and they then can say that you have been warned!
Just take the following in consideration when OverSizing a CD-R:
1. There is a possibility that it can damage the CD-Writer.
2. Some CD-Writers can't physically move the carriage up to the end of the pre-groove and so can't overburn up to the quantity of the blank.
3. Some CD-ROM player can't move their carriage far enough too play an OverSized CD-R.
4. The quality of media can be lower than in the normal part of the CD-R.

INFORMAZIONI PRE-GROOVE
Every blank CD-R has important information encoded on the CD-R itself. This information is called the pre-groove or ATIP and without it no recording is possible.
The following information is stored in the pre-groove:

The capacity of the disk

The manufacturer of the disk

The formulation of the disk

The type of disk (for example the audio CD-R's for audio CD recorder)

The supported writing speed

Hint at each speed for the recording algorithm to use

Absolute time from the start of the disk

last possible address where data can be written (TotalSpace)

last possible address for the last lead out. This is the last possible address/position where a lead out can start (from this point on, a complete lead out can be written on the CD-R).
Only a CD-Writer can read the pre-groove, a CD-ROM drive usually can't (as it doesn't need this info to play/read a CD)

CD-R DA 80 MINUTI
80 minutes CD-R's can also be OverSized upto 83:30 minutes DATA (= 734 Mb DATA & 842 Mb AUDIO)!

TERMINI IMPORTANTI

OverSize: Write DATA past the physically set TotalSpace, this is accomplished by shortening the lead-out area and using this area for DATA.
This feature can only supported by a few CD-Writers.

OverTime: This term has nothing to do with OverSizing, it is used in EasyCD Creator (3.5) to define the time between 74 minutes and the TotalSpace time.
For normal 74 minutes CD-R's the Overtime is maximum 1 minute, for 80 minutes CD-R's it is around 6 minutes.
This "feature" can be used by any CD-Writer.

DAO: Disc-at-Once is a method of writing in which one or more tracks are written in a single operation. The laser will not stop until the whole CD-R recording is finished and the CD-R is closed. Hence no Run blocks and no clicks between audio tracks.

TAO: Track At Once is a method of writing where the laser beam stops at the end of each track and then restarts. This can cause a glitch when playing audio CDs recorded in this way. Track-At-Once is generally used to create multisession and ISO CD's.

Lead Out: Every CD-R manufacturer has to put at least 90 second of pre-groove past the reported length because the standards say there should be a
lead-out of 90 seconds past the end of user data.

SCRIVERE UN DISCO OVERSIZE USANDO NERO
Perform the following steps to perform an OverSized CD-Copy:

Start Nero

From the action-bar select File and select Preferences.

In the Preferences window, select Expert Features (or Advanced settings for older versions) and select the Enable oversize disc... feature.

Choose a Maximum CD Length and click OK (82:59:59 is the maximum value that can be entered) and be aware of the risks explained in the warning.

From the action-bar select File and select CD Copy.

A window will appear when a CD is copied which is bigger than 74 minutes, click [OK] to start the oversize copy.
The OverSize feature also works fine when creating your own projects. Keep in mind that it will only work with CD-Writers that support OverSizing.

SUGGERIMENTI DI SCRITTURA
When you create a normal ISO9660/Joliet CD-R then the following settings must be set to write as much data as possible to this CD-R:

CDR Fixation
Close the CD-R so that no further session can be added. This saves about 10 Mb of Leadin/Leadout space which otherwise is needed for the next session.

CDR Write Mode
Select the Disc-At-Once mode (also called Session at once)