Delta Patcher is the graphical window in front of xdelta, maintained as a GPL-2.0 program for Windows, Linux, and macOS. The version I cite is 3.1.6 dated 18 Aug 2025. It creates and applies VCDIFF patches. That is the job the browser refuses once the image is a DS card, a GameCube ISO, or a PS2 DVD. The desktop tool can stream. A tab has to hold the bytes. I send people here when the online apply stalls, not because the patch is fake.
The settings that matter are the ones xdelta3 already has. Secondary compression is the trap. A patch built with the default LZMA secondary compressor opens here and may fail in an old browser decoder. This site's pinned engine understands DJW and LZMA. If you are creating a patch for someone on an older site, set the secondary compressor to none so their tool can read it. Delta Patcher is where that choice is visible. The browser module does not create xdelta at all.
Smash Remix and other large N64 diffs are a common reason this program is named in a readme. The base file is still a byte-order problem. Delta Patcher will not swap .v64 to .z64 for you. Do that first, then apply. I keep the N64 page for the shuffle and this page for the window.
xdelta3 on the command line is the same math without the window. I mention both so a Linux user who already has the package does not think the GUI is required. Related pages: xdelta format, NDS, GameCube, PS2, and the secondary decompressor error.
