dBu battle recordings

Original compositions: ZUN / 上海アリス幻樂団. Arrangements and recordings: どぶウサギ / dBu music (artist site).

Imported on 2026-10-10 from the three matching NCM files supplied by the site owner in their local music library. The embedded media was MP3. Its audio packets were copied without re-encoding; container metadata and cover art were removed. Packet hashes were compared before/after the copy. Original library files were left unchanged. These music recordings do not inherit the website’s software license. The archived ensemble arrangements have separate credits and permissions.

Final-file SHA-256:

80113f6048c1e00ca16e4b0cffe4a4cc7c824210aeaf42163d50327d35bd1eed  alice-dbu.mp3
33c80e30f1212dc7feb1f6878279eb55ddbe54593301824621a01e3caad1615b  marisa-dbu.mp3
d8bc51cc6ff26f263af0e0af9ca246d2b29e126cc9c82610393405aacf700b74  patchouli-dbu.mp3

Musical timeline

assets/js/games/danmaku-score.js stores estimated onset-aligned beat times and per-four-beat normalized RMS energy. Nominal tempo guides are 159 / 167 / 150 BPM; the actual arrays retain timing changes instead of assuming an exact, constant tempo. These are automatically measured musical cues, not an official note chart or hand-transcribed score. Runtime analysis is unnecessary, so muted play neither downloads nor decodes music.

Reproduce the analysis in an isolated Python environment with librosa and numpy, and FFmpeg available:

python scripts/analyze-danmaku-music.py --ffmpeg /path/to/ffmpeg --output /tmp/beatmap.json

The script uses mono 22,050 Hz decoded PCM, a 256-sample hop, beat tracking with tightness 110 and a fixed nominal tempo guide, and RMS normalized by its 85th percentile. MP3 container duration can include encoder padding; timeline durations above use decoded PCM. Beats trigger waves and half-beat accents; six encounters are spaced across each recording at sixteen-beat boundaries. The last 24 beats of each encounter allow its result and distinct nonspell; consecutive quieter bars can begin that passage earlier. The mixer follows the fixed-step game clock, including late enable, pause, resume countdown and looping. Radio/PV music is independent.