By '"hi-rez" FLAC vs regular FLAC"' the parent post means something like 24/192 vs 16/44.1, not the amount of compression. It has a higher resolution than the other example.

24/192 flac as opposed to 16 bit flac. flac/mp3 is about compression, bits and khz are about sampling/representation.

Greater than 44.1khz sampling rate and/or 16bit depth.