dvdisaster - provides a margin of safety against data loss on CD and DVD media caused by aging or scratches.
dvdisaster creates error correction codes to compensate read errors which are not correctable in the CD/DVD drive.

It also tries to read as much data as possible from defective media. Afterwards unreadable sectors are recovered using the previously created error correction code. The maximum error correction capacity is user-selectable.
If you create the error correction code file 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.