Unix or Linux command to compare binary files

I'm looking for a command that compares binary files. Of course, I know about diff, but it is not very good at binaries. I have two files from a error-prone source (scratched dvd) which should be equal but aren't. (Well, realy more than two, and I get about 6 different md5sum out of 15 samples.) I'm looking for a tool that lists the positions where the files differ. --- In addition to the accepted answer, xxd looks good as it can also be used to change back edited hex-files to binary.