is a lossless compression format originally developed by Nicola Salmoria for the MAME (Multiple Arcade Machine Emulator) project. Unlike the more common ISO or CSO formats used for PSP games, CHD is designed specifically for archiving media.
The ultimate dream for archivists is a submitted to the Internet Archive as a single torrent — possibly as a “PSP Redump CHD Collection” with official metadata. Several groups are working on this, though legal concerns keep them anonymous. psp chd internet archive extra quality
Devices like the Steam Deck, Retroid Pocket 5, and Anbernic RG556 can emulate PSP flawlessly — but storage is often limited. A full PSP CHD set (~400 games) can fit on a 512GB microSD card, whereas the same games in ISO format would exceed 1TB. For mobile gamers, that efficiency is transformative. is a lossless compression format originally developed by