CD Burning – The Differences Between Track-at-once and Disc-at-once

All of us who own a personal computer have burned at least a CD or two in our days. Being able to download music and create your own mix CDs has been one of my favorite features since the beginning. Software such as iTunes and Nero has made this task even easier, pretty much doing all the work for us. All you need to do is insert your CD-R into your CD burner, pop open either one of those programs, drag in your audio files, and hit the burn button. In a couple minutes your CD is ready to go. But wait a second, what about these options like burn speed, and should I choose disc-at-once or track-at-once? Well, today we’ll be attempting to get to the bottom of one of these confusing options. We’ll be discussing what the differences are between these two CD burn modes; track-at-once and disc-at-once, and to decide which one is the right option to choose for your project.




Track-At-Once



This is the first option that was introduced when CD duplication software was first created. With this mode, each time a track is finished burning, the laser recording the information stops. When it stops, two run-out blocks of data are written. After that, one link block and four run-in blocks are written when the next track begins to record. With track-at-once, you may burn both data and audio on the same disc. These blocks in between tracks are not a problem when data is being read, but you may hear a click on some CD players when playing back audio. This is something that may cause you problems if you are having your disc mastered and duplicated or replicated at a professional facility. In that regard, track-at-once is best suited for CDs for personal enjoyment.

In Detail Track-at-Once recording is what most recorders and software support today. Each time a track is finished, the recording laser is stopped, and two run-out blocks are written. When the laser is started again to write another track, one link block and four run-in blocks are written.




These blocks don't affect data tracks because you never read between data tracks, but they are a problem for audio because in some audio players you might hear a click when the link and run blocks are encountered between tracks. These link blocks may also cause problems if a disc is to be mastered and duplicated at the factory, and many disc replicators refuse or remaster Track-at-Once discs. For professional audio use, you need Disc-at-Once.



Note: Another cause of clicks between tracks is the CoolWave audio-editing shareware. It includes header information which is recorded as a click on CD-R. Use another editor, or check the Internet for patches to CoolWave which strip the header information




Disc-At-Once



This burn mode takes all of your data, be it audio data or regular data, and burns it all to disc in one big block. No gaps are added between tracks, the laser never stops burning the data to disc. This is a newer feature, which should be an option in most modern CD burning software. One option you have with disc-at-once mode, which is kind of interesting, is that you can place allows any amount of audio data (or no data at all) to be written in the "pre-gaps" between tracks. With this option, you can place track introductions between each song. This is cool, because you can create “hidden tracks” on the CD in the pre-gap areas, that are only accessible by rewinding backwards into the pre-gap area. This is the ideal choice for CD masters that will be going to a CD duplication or replication house.


In Detail Disc-at-Once recording, all tracks are recorded without ever stopping the laser, and the disc is closed. Hence no link blocks and no clicks.




Disc-at-Once has only been added/available with the recent generation of CD recorders and recent firmware upgrades.



Note: Track-at-Once recording has nothing to do with the length of the gap of silence between audio tracks! Disc-at-Once recording is a prerequisite for being able to control the length of the gap (down to zero seconds), but it is not the only one. For the moment it is not possible to control the length of the gaps between tracks with any version of Easy-CD Pro.


I hope that this fully explains these two different CD burning modes for you, or at least explains it enough for you to successfully create your next CD mix or master. I was going to leave out explaining burn speed for another article, but it really is simple enough to explain at the tail end of this article. Basically, your burn speed should be15-30% of the drive's maximum capacity. I.e. For a 52x burner, the optimal burn speed would be from 12-16x. It’s as simple as that. Thanks for reading this article, and best wishes on your next project!

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