It merges messy multi-file formats (like .BIN and .CUE ) into a single, tidy .CHD file.
Unlike other compression methods (like ZIP or RAR), CHD is designed specifically for disc images. It compresses the disc's data sectors intelligently, removes redundant headers, and can store metadata about the original disc's structure (tracks, pregaps, ECC data). For PSX games, which were stored on 650–700 MB CDs, the results are remarkable. chd psx roms 2021