[RndTbl] Problem Reading DVDs

For some reason we have a stack of DVDs that must have been burned in some strange format. When I put one in my DVD drive the drive refuses to recognize it. When I try to mount it, it simply says "no media". What I would like to do is take a "raw" image off the disk, so I can try to recover it. Something similar to what would be done with "dd" on a hard disk. dd if=/dev/hdc of=/tmp/file But again, it just says "no media". Is there a way to "force" a mount or some other technique so I can read the disk? Or any other suggestions as to how to recover the data? John