CHD, which stands for , is a lossless compression format originally developed for the MAME arcade emulator. It is designed to perfectly preserve the data of disc-based systems—like the PSP’s UMDs—while significantly reducing file sizes.
: It converts multi-file disc images into a single, clean file. Why "Extra Quality"? psp chd internet archive extra quality
: Optimized settings (like 2048 or 4096 sector sizes) that ensure the best performance on emulators like RetroArch and PPSSPP . PPSSPP warns about bad performant CHD while using ZSTD CHD, which stands for , is a lossless
: Modern emulators like PPSSPP can read CHD files more efficiently than heavily compressed CSOs, often preventing audio stuttering or long load times. Why "Extra Quality"
: Being lossless, it ensures no game data is discarded during compression.
Unlike older compression methods like CSO, CHD is often preferred because it:
: Use of the Zstandard (ZSTD) compression algorithm, which offers an excellent balance between high compression ratios and fast decompression speeds.