If you have souch files burned on XCDs you can read them with XCDextractor and even try to repair them.
Repair algorithm is not so sofisticated, indeed is fairly simple, but the goal here is to read the whole file despite the presence of errors because, if you have the file back on hard disk, you can at last try to repair severly damaged sections.
XCDextractor has another functionality: the creation of info file, that must be burned in the same directory of the .dat file and is really handfull when you want to extract it. It contains the exact file size (lost when creating .dat) and CRC32. Without the info you can activate "Try to guess file size" checkbox and it will remove all tail zeros from the end of the file.
The advantage of burning movies in XCD format is that you have remarkable extra capacity (800Mb from a 700Mb CD) at the expense of error correction codes and the possibility to read back the movie files to the hard disk (or other storage media).