sysutils/dvdisaster 0.79.10_1 FreeBSD

dvdisaster provides a margin of safety against data loss on CD and DVD media caused by aging or scratches.

\* dvdisaster creates error correction data to compensate read errors which
  are not correctable in the CD/DVD drive.

\* dvdisaster tries to read as much data as possible from defective media.
  Afterwards unreadable sectors are recovered using the previously created
  error correction data. The maximum error correction capacity is
  user-selectable.

\* dvdisaster operates at the image level and does not depend on the file
  system.

If you create the error correction data in time and keep it at a safe place, you have a good chance of recovering the medium contents from typical read errors and to transfer your complete data onto a new medium.