PFI, lead-in information, etc

I’d like to learn everything I can about the lead-in area (which contains PFI, etc).
I’m working with a very thin mini-CD that seems to work about 50% of the time in some of the newer drives. It was more reliable in older drives.
Currently, I can put it in a drive and sometimes it’ll recognize it as a CD and sometimes it can’t tell. Eventually, after multiple tries, it’ll work. I’d like to get this percentage of success up to a greater degree and so I was wondering if there’s a problem with the lead-in.
I had the company that stamps the CD to check it out on their diagnostic machine. This thing costs around a million bucks. It says the discs are 100% correct. However, I’m still having this problem, so I’m trying to figure out what’s different with the newer drives.
I was wondering if I were to relocate the lead-in slightly, would it possibly be in a more readable area, or if there is error recovery areas that I can place in the lead-in, to push the PFI and other stuff further a bit, so that they’re more readable by the newer drives.

Anyway, I know this isn’t the type of thing that usually gets asked, but since the drive manufacturers aren’t real cooperative, I was trying to figure out how to solve this problem.

Since it is a pressed disc, you can not alter it in anyway. Also, CDs do not have PFI. The PFI (physical format information) is a part of DVD.

Maybe you can make a CD-R copy of your mini CD that would be more reliable.


I.m authoring the cd and it needs to be with this thin miniCD. whatever I need to fix the lead-in I want to learn more about

Perhaps there lies your problem: “thin” mini-CD, which sounds out of spec. As RichMan said, you can’t alter the pressed CD, unless you meant to say blank “thin” mini CD-R, so you can’t use a normal mini CD-R?

Maybe the clamping mechanism of newer drives are weaker than older ones. If this is so then it has nothing to do with the lead-in.

Anyway, here’s some info about lead-in:

Lead-in are just normal sectors formatted as CDDA or CD-ROM. It contains the TOC which is defined by the sub-channel Q data, and not from the main channel 2352 bytes.

TOC contains:

  • first track number
  • last track number
  • index 1 times of each track - considered as start of track
  • start time of lead-out
  • data type: CDDA or data

TOC is repeated in the lead-in.

So, you are talking about a CD and not a DVD, correct? What type of CD is it (ROM or Audio)? What software are you using to burn the disc?

If you are sending your files to a factory and having them make replicas for you, what types of files are you sending or are you sinding them a playable CD-R? Also, the encoder that they use is what is writing the leadin so this is out of your control. You only get to tell them how many tracks and where they start.

If you make a new copy of the CD and it also has problems, you should try a different burning software.