Drag and drop your .cso files directly into the ISO folder.
A classic, user-friendly graphical user interface (GUI) tool for Windows. It allows you to easily convert files bidirectionally between ISO, CSO, DAX, and JSO formats.
Another legacy GUI tool that supports converting between ISO, CSO, DAX, and JSO formats. Step-by-Step: How to Compress an ISO to CSO
When archiving a PSP ISO into a CSO file, you can choose a compression level ranging from 1 to 9:
When developers or users dump physical PSP Universal Media Discs (UMDs), the resulting file is an ISO. While ISOs are perfect structural clones of the disc, they often contain large amounts of dummy data or uncompressed audio and video files. The CSO format compresses this data, significantly reducing the file size. ISO vs. CSO: A Quick Comparison
In the broader context of PSP archiving, the community utilizes several formats, but CSO remains the "de facto" standard.
Note which games run flawlessly as CSOs and which ones require ISO format on your specific custom firmware. Conclusion
For a truly robust "CSO PSP archive," moving beyond basic compression can be very helpful.
To clarify:
The format wasn't static. Its evolution has brought notable improvements:
While CSO archives are highly efficient, compression can occasionally introduce quirks. Here is how to solve the most common issues: 1. Game Lag or Audio Stuttering
Maximizes your storage savings but compresses the data tightly. The Impact on Hardware vs. Emulation