It’s in our culture. How much is enough? More. We always want more. A few inSync readers have inquired about being able to write more than 74 minutes of audio to a 74 minute CDR claiming they’ve “heard” it can be done.
Yes, it in fact can be done under certain special circumstances. CDR’s have a pre-formed spiral track, and the sector addresses are hard-coded into CDR media, so there’s no flexibility. Every disc holds a predetermined amount of data. The capacity of a CDR is calculated to allow enough space to hold at least 74 minutes of Red Book audio data and 90 seconds of digital silence. The silent area is called the “lead-out”, and is included so that a CD player will realize that it has reached the end of the disc, especially when fast-forwarding. When a recording program tells you the exact capacity of the disc, it’s not including the area reserved for the lead-out. There’s nothing magic about this reserved area though. With the right kind of setup — and a willingness to accept write failures as a matter of course — you can put data into the reserved area, and possibly even a few blocks past the end of it. This is often referred to as “overburning” a disc. How much more you can fit depends almost entirely on the media. Some brands will hold as much as 78 minutes, but it varies from batch to batch.
The real trick is you need a CD burner that can do it, and you need software that gives you the option. Most commercially available CD burning programs don’t mention anything about overburning discs, but there are some programs out that do allow this option. Two that come to mind are CDRWIN and Nero Burning ROM. As for mechanisms, the Teac CD-R55S, Plextor PX-R412C, Yamaha 4xx/4xxx, and Memorex/Dysan CRW-1622 units have been used to write “extra long” audio discs successfully. The recent Philips, HP, and Ricoh units don’t seem to be as willing to do so.
Finding exactly how much data your discs will hold is largely a matter of trial and error. You basically just try to burn a disc about 80 minutes long. It will fail somewhere before then. You can put the failed disc in your CD player and see where it stopped writing. Keep in mind that the display in your player will show the full 80 minutes (because this is how the TOC was written), but the disc will actually stop playing before that. This is the “true” capacity of your disc. Other brands and types may record more or less.
So there’s the information. Do with it what you will, but keep in mind that not only are these extended CDR discs going to be harder to make, they are likely going to be less stable over time. Another way to get past the 74 minute barrier is to use the new 80 minute media. While currently much more expensive than 74 minute discs you don’t have to waste as many making a good one. Of course these same tricks work on 80 minute discs as well so it’s just a matter of time before 80 minutes is no longer good enough.