Infinite ideas. Human music.
XJ is a music engine — patented machinery that composes continuous, never-repeating music from material recorded by human musicians. Authored by composers. Running in games, streams, and spaces.
XJ turns composition into a system. Composers author a library of musical modules — melodies, rhythms, harmonies, instruments, transitions — and the engine assembles them, live, into one continuous score that never repeats.
Every sound in an XJ score was played by a person. The machine decides only what to play next — no models, no training data, no cloud. The engine runs on your hardware, and every output is rights-clean by construction.
Compose
Musicians author the source material: chords, grooves, phrases, stems. Real performances, recorded by people, organized into templates the machine can read.
Arrange
The engine selects and voices that material in real time, obeying the composer's rules of harmony, meter, and tempo — segment by segment, forever.
Evolve
Each segment builds on the one before it. The score develops like a living thing: hours of coherent music from a finite library, and no two passes alike.
Meme
State goes in. Your game, stream, or app sets memes — mood, chapter, intensity — and the engine honors them in the very next bars it writes.
Sequence
Macro and Main programs chart the long arc: which song, which chords, which voicings, in what order.
Arrangement
Beat and Detail programs choose the parts, and Instruments supply human-recorded audio for every voice.
Morph
Transitions are composed, not crossfaded. Meter, tempo, and key stay continuous through every change of scene.
Output
The C++ engine renders one coherent mix — in your game, on your stream, in your space. No servers required.
| Model | XJ · generative music engine |
|---|---|
| Patent | U.S. Patent 10,446,126 B1 — System for Generation of Musical Audio Composition |
| Workstation | Desktop DAW for authoring adaptive music — Windows · macOS · Linux |
| Engine | Portable C++ runtime library — embeds in any audio stack |
| Game integration | Unreal Engine 5 plugin |
| Source | Open source at github.com/xjmusic/xjmusic |
| Station | 37.7536°N, 122.4884°W — San Francisco, California |
THE HERO'S JOURNEY · UNVEILED AT GDC 2024
Author possibility spaces, not tracks.
The XJ workstation is a DAW built only for adaptive music: a vertical timeline, program types made for variation, and aleatory tools that keep a score alive.
Ship an adaptive score, not a middleware fight.
The engine is a portable C++ library that plays the composer's export verbatim — and the Unreal Engine 5 plugin drops it straight into your project.
“XJ is an extraordinary tool in the kit for composers, allowing them to elevate their capabilities and produce a new level of work”
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