Introducing ManiaGAI v2 — Better Timing, More Control, Faster Generation

ManiaGAI v2 went live on October 1, 2026. This Blog didn’t exist yet, so there was no launch post at the time. This is a look back, written on October 9: what version 1 was, what version 2 replaced, what followed, and what is still missing.

Where version 1 left off

dancegai.com launched on July 7, 2026 with the core loop: upload a song, generate on a cloud GPU, download a playable osu! mania .osz. Within days it detected timing automatically, handled songs that change tempo, and — from July 11 — produced a whole mapset per song, each difficulty named by its measured star rating. Version 1 was closed out on the research side on July 12.

It worked, but it was slow — a minute or more per mapset — and it left players few choices. August and September went into the two things players feel most: timing that is right on every kind of song, and a much larger, cleaner training corpus.

What version 2 replaced

Version 2 wasn’t an update to version 1. It replaced the whole generation pipeline in production on October 1.

Timing v2

A new timing detector, built on the open-source Beat This beat tracker and our own grid fitting. On our benchmark of 2,501 ranked steady-tempo songs, it matches the mapper’s timing within 40 ms on 97.1% of them, up from 90.7% for version 1 — and on those songs it never added a false tempo change. The full benchmark, including where the open-source Mapperatorinator does better, has its own article.

New models, trained on far more data

Both models were retrained on the new timing grid, on a corpus that had grown from about 83,000 charts to 150,622 charts by about 14,500 mappers. A silence guard was added so nothing is ever charted over a silent stretch of a song. (What’s in that corpus.)

Several times faster

A full mapset went from a minute or more to about 20 seconds of GPU time — typically 13 to 25 seconds, depending on the song and the difficulties. Songs are prepared in the browser while you pick settings, every difficulty is generated in one batched pass, and GPU workers start from a snapshot. (How we made it fast.)

A generator with real choices

• 4K to 9K — 8K and 9K were new.
• Any choice of difficulties from ★1 to ★10, pre-selected from ★1 upward as far as the song’s length allows.
• Style controls for long-note ratio, inverse long notes, jacks, short long notes and delay.

Those controls exist because of how v2 is built: a planner decides each section’s gameplay before a note model places the notes, and difficulty and style act on that plan. Why ManiaGAI uses a Planner + Noter.

The weeks after

Version 2 kept moving after launch day:

• October 2 — each difficulty got its own style, calibrated from real charts at that key count and star rating; the models were retrained with three fixes for long songs, tempo changes and section alignment; and the Technology page went up.
• October 3 — import from osu! (paste a beatmap link and only its song is used), the whole site in 15 languages, a redesigned three-step generator, a preview player and share pages.
• October 4–5 — sharing settings and a public Gallery, then Gallery maps that play with their song and download for their first 7 days.
• October 7 — ManiaGAI v2.1, a major quality upgrade to both models. Every generated chart now carries the version that made it.
• October 8 — generation about twice as fast, with exactly the same charts.
• October 9 — the Gallery became Community Beatmaps, where new maps appear by default.

The full list, entry by entry, is in the changelog.

What version 2 means for players

Version 1 answered “can an AI make a playable osu! mania chart of my song?” Version 2 changes the question to “which chart do I want?” — which key count, which difficulties, which style — and answers fast enough that trying another option is cheap. A generator you can steer is a different product from one you can only re-roll.

What’s still missing

• Fixing one section. The note model can regenerate a selected part of a chart while keeping the rest, but the editor built on it is still in internal testing — today, a change means a new generation.
• Style by example. Style is five dimensions on sliders; describing a mapping style by example is a direction, not a feature.
• Long songs. A song gets fewer difficulties the longer it is, and songs over 10 minutes are flagged before you generate.
• Timing evidence on tempo changes. Our published timing benchmark covers steady-tempo songs only.
• Other games and modes. osu! mania is still the only output format.

If you want the whole arc rather than one release, our story tells it month by month.