How to diagnose/repair bad FLAC files?

I was trying to listen, on my iMac (10.14.1) to some FLAC files I'd gotten a while back and never tried. While some are fine, others stop 30 seconds in or fade out halfway through. I've tried playing them on VOX and VLC, and the result is the same on both. Is there a Mac app to scan a folder of music to identify bad files and/or to repair these corrupted files?

Thanks in advance