PPF vs IPS
PPF and IPS are not really competitors. PPF was designed for CD and DVD disc images, where files are hundreds of megabytes and the size normally stays put. IPS was designed for cartridge ROMs and cannot address past 16 MB. Neither verifies your file on this site, so check it yourself first. Pick based on what you are patching.
PPF for disc images, IPS for cartridge ROMs.
| PPF | IPS | |
|---|---|---|
| Designed for | CD and DVD disc images | Cartridge ROMs |
| Maximum target size | No practical limit | 16 MB |
| Can change file size | Can grow only | Grow or shrink |
| Verifies your file | Not on this site, in any version | No |
| Typical systems | PlayStation, PS2, Saturn, Dreamcast | NES, SNES, Game Boy, Genesis |
Two formats for two different jobs
PPF writes changes at absolute offsets into a large image, which in normal use leaves the size alone and keeps the disc structure and any accompanying .cue file valid. It has no way to shorten an image, though a record past the end will lengthen one. IPS does something similar in spirit but with 24-bit offsets, capping it at 16 MB and ruling out disc images entirely.
You will essentially never have to choose between them, because the file you are patching decides for you.
Frequently asked questions
Can I use an IPS patch on a PlayStation ISO?
Practically never. IPS offsets cap out at 16 MB, so the format cannot describe a change anywhere past that point in a disc image. PPF or xdelta is what those projects use.
Does PPF verify my disc image?
Not on this site. PPF 1.0 stores no verification data at all, and although PPF 2.0 and 3.0 can carry a 1024-byte sample of the original image, this patcher reads that block without comparing it. Check your image against a redump hash before patching.