Copying using a fast copy (on the fly)
Nero can perform a fast copy (on the fly) straight from the CD-ROM to the recorder without using an "intermediate" image file.
Some of the disadvantages listed below do not apply to recorders which have a mechanism (BURN-Proof, Just Link, Safe Burn, etc.) to prevent a buffer underrun thereby making the burn process more stable. This is a simplified version of how it works: if the data is not supplied quickly enough the recorder interrupts the burn process, waits until there is enough data in the buffer again and continues to write at the same point.
Advantage
This feature, which is often desirable, allows faster copying and also requires no additional storage space on the hard disk.
Disadvantage
The advantage of speed may also become a disadvantage:
- Firstly there must be a CD/DVD-ROM drive available which can supply data fast enough. For example if you want to burn 24x the input data must be able to be read in at least 24x (better with 32x) from the CD/DVD-ROM so that no buffer underrun occurs. It is not so easy to guarantee this because some CD-ROM audio data reads considerably more slowly than "normal" data (Mode 1 or Mode 2). For example there are modern 48x CD ROM drives which read audio data slower than 10x!
- If errors occur when reading the CD - because there is a scratch on the CD for example - the error cannot possibly be eliminated by reading the appropriate point of the CD several times because, unlike the image file approach, there is no time (threat of buffer underrun). In such a situation there is nothing else Nero can do but write the questionable data received or just null data. In other words direct copies are very susceptible to read errors!
- Many CD/DVD-ROM drives are unable to provide information about the number and type of sessions. They can only give information on the number and type of tracks. This means that Nero sometimes cannot prepare an exact copy of a CD.
- Audio tracks may contain index positions. However these can only be identified if the appropriate point on the CD is being read. When producing a "disk-at-once" copy this information does have to be available before the burn process is begun. This means that with fast copies Nero cannot copy audio index positions at the same time. These will therefore inevitably be lost!
- The quality of audio data read in may suffer here. Nero's method of copying a CD is such that some megabytes of data are read from the CD/DVD-ROM and then written onto the recorder. This inevitably occurs because Nero does not have enough main memory to record the entire CD (sometimes more than 700 MB!) and no image file is to be made (even a fast copy (on the fly)). The CD/DVD-ROM drive often reads at higher speed than that at which the recorder can write the data. This means it is possible for Nero's internal buffer to be unable to accept any more data. This can lead to a situation where the CD/DVD-ROM drive has already read audio data in its internal buffer (cache) but has not yet been able to "deliver" to Nero because Nero's buffer is full. This means that the CD/DVD-ROM is forced to reposition the reading head. As the CD is turning continuously in the CD-ROM/DVD drive, the reading head has to jump back to a previous position. Many CD/DVD-ROM drives cannot adjust the reading head for audio CDs accurately and therefore sometimes invalid audio data is transmitted.
The fast copying of a CD requires at least one CD/DVD drive and one recorder to be connected.
Here is a step-by-step account of how to produce a CD/DVD with Nero using a fast copy:
All settings may be left at their default values.
- Place the CD/DVD to be copied in the CD/DVD drive.
- Place an empty CD/DVD in the recorder.
- Start a new compilation by clicking on the appropriate button or the File menu and the command New.
- Click on the Copy CD icon - the Burn tab is in front. Set the procedure for copying CD and/or DVDs on the tabs.
- Click on the Copy Options tab and activate the "fast copy (on the fly)" control field.
Note: If you are unable to activate the control box the read drive is also the burn drive. In this case click on the drop down button and select another drive. If necessary you can also change the read speed of the chosen CD/DVD drive.
- Click on the Read Options tab and decide how Nero is to behave during reading.
- Click on the Burn button to start the burn process (or the simulation - depending on the chosen option). Nero now runs all the necessary stages selected. A status window will appear showing the stages implemented and informing you how the burn process is progressing. As soon as Nero has completed the write process a window will appear showing a result e.g. "burn process 12x (1800 KB/s) successful".
- Click on the OK button to close the dialog box. The CD is then ejected. The messages shown can either be saved, printed or discarded. Close the window by clicking on the Discard or Close buttons.
- You can now check what has been written on your CD by reinserting the CD and clicking on the CD-Info icon.
See also:
Copying using an image file
Verifying audio read quality
Setting speed on CD/DVD-ROM drives