Turbo codes don't add a lot of overhead if you just want to protect against 1 bit flip per byte or so via FEC (forward error-correction), they're close to the Shannon information entropy limit in efficiency but I don't know of any open source implementations, and implementation details such as "I want to protect against at most 2 bits per byte" or "I want to protect at most 5 bytes per kilobyte" directly matter in the implementation.

I've been wanting to try to understand them to see if I could implement something myself for a while now