Detecting Capacity Of Media


This may be a simple question, but i’m having troubles detecting whether the inserted blank CD is either 74 or 80 minutes - or better how much space is available whatever media is inserted. I’ve tried using the READ_DISC_INFORMATION command and checking the Last Possible Start Time for Start of Lead-out field, but this gives some strange results with the discs i’ve checked - although obviously i could be doing something wrong here.
I was just wondering which commands / data others used to determine how much capacity is available for writing on a blank disc.


Nero CD-DVD Speed will tell you.

Thanks for your reply, however i am writing my own software and was wondering which mmc commands people use - i’ve written the writing side of it, i just need to tidy up the functions to deal with all cases. One of which is to detect if there is enough available space for the data that needs to be written.


The best bet is to use the READ TRACK/RZONE INFORMATON. This, amongst other things, contains the LBA of the next writable address and the number of free blocks. You can then do the sums to see if it 74 or 80 min.


I had the same problem!
I’m doing it by READ TRACK INFORMATION command, with the track no set
to FFh (Invisible or incomplete track).
I use the “TrackSize” in the “Track Information Block” to determine the
disc size in blocks.