Note: perfconv is pretty much incomplete, it may not actually work as intended, or just outright make garbage charts. keep in touch and check back later for new updates.
perfconv is a tool for converting song charts for the Performai rhythm game family:
- CHUNITHM
- maimai DX
- O.N.G.E.K.I
This tool is for converting proprietary arcade charts into a format compatible with other simulators.
This project is for interoperability and educational use only.
It is not a replacement for the official games, nor does it include any copyrighted music or assets.
The Performai series — CHUNITHM, maimai DX, and O.N.G.E.K.I — are still actively developed and supported by SEGA, primarily in Japanese arcades and a few licensed international locations.
This project is not a replacement for the official games. It does not intend to compete with or undermine SEGA's work.
Instead, this tool exists to support:
- Content preservation
- Community-driven simulation
- Cross-compatibility tooling
- Access for regions with no arcade availability
We encourage players to support the official releases where available. This is about keeping the games alive when they’re otherwise out of reach — not replacing them.
Science. Why not? I can go on for hours about how I just see these things as puzzles to solve, but the short answer is:
Because I can. Fuck you.
...Also they're just plaintext data, no binary shenanigans so eh, no use gatekeeping plaintext either.
No.
The real danger is relying on fragile simulators, closed-source tools, and scene politics to preserve games.
Porting charts keeps content alive when the corporations won’t.
Then so be it.
I’m not here to cater to a single paranoid Japanese indie dev who treats community content like personal property and melts down over people doing things “the wrong way.”
If a sim can’t handle real-world content, it’s not a viable platform — it’s a toy.
This project is a vote of confidence in open source simulators and developers who actually care about openness, contribution, and sustainability — not control, fear, or fragile egos.
Hell, at that point I might as well make another osu!. EBA/Ouendan died and was replaced by a FOSS project that actually cares about the community — why can't we do the same here?
See:
Good. Let them.
Maybe then they’ll notice there’s demand and finally release a real home version — like that other company that offers a subscription-based PC client (VPN-only or not).
Until then? Players will play however they can. Or keep playing the blue hedgehog game instead.
That's not how this works.
Nobody downloads decrypted arcade dumps and builds cross-platform simulators just for novelty. If they’re doing this, they already love the original game.
Arcades will always be the better experience — from cabinet feel to social atmosphere — and people will still go when they can.
This is about keeping games playable when they can’t be played any other way — especially when puritanical soccer moms throw a fit over anime cleavage and kill off international releases.
The scene fragmented itself — by:
- Hiding tools
- Hoarding charts
- Gatekeeping contribution
- Letting fear dictate development
This project exists to reunite players through openness and preservation. Because when the devs give up? We build anyway.
Technically, yes — if a user provides the original files, they can convert them. But:
- This tool does not distribute or include any official content. That’s entirely on you.
- It’s intended for interoperability: reading, converting, and creating charts from modded installs, fan-made content, or simulator formats.
- Redistribution of official charts or converted data is not endorsed or encouraged by this project.
- Use of this tool with proprietary content is at your own risk. The maintainers take no responsibility for what you do with it.
We provide the tool — you are responsible for how you use it.
As per the GPLv3:
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
If you're converting from a real disk dump, do not share the disk image or original data files.
You may use converted charts in compatible simulators, but distributing the original or converted files is strongly discouraged.
Still confused?
➡️ See USAGE_POLICY.md for more.
This project is licensed under the GNU General Public License v3.0. See the LICENSE file for details.
This project contains no original game content, no copyrighted music, and no assets from SEGA or its affiliates.
Use responsibly. Fork freely.