The dvdisaster project:
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.

WWW: http://dvdisaster.net/