38 lines
2 KiB
Markdown
38 lines
2 KiB
Markdown
# Sonification v1
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Sonification is an interpretive presentation layer, not an objective artwork feature. The API
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returns deterministic synthesis parameters; sound is produced only after a user action by the
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browser Web Audio API. The frozen profile set is `1.0.0` and is materialized as
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`data/processed/sonification-profiles-v1.json`.
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## Weighted color tone
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`weighted-color-tone-v1` maps the enrichment-weighted OKLab centroid to one sustained tone:
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- hue uses twelve equal 30-degree bins, `floor(hue / 30)`, mapped C through B;
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- undefined achromatic hue maps explicitly to A and reports `achromatic_neutral`;
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- centroid OKLab lightness sets a target register from MIDI 36 through 84, rounded to the nearest
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MIDI note in the selected pitch class;
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- centroid chroma controls velocity, palette spread controls harmonic richness, normalized
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palette entropy controls a small noise component, hue concentration controls tonal purity, and
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dominant weight controls attack and release.
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All controls are clamped to documented safe ranges in `sonification/profiles.py`.
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## Physical artwork tone
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`physical-artwork-tone-v1` uses the same hue and timbre mapping, but inverse log-area percentile
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sets register: larger physical works sound lower. Signed log aspect ratio produces subtle stereo
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pan via `0.6 * tanh(log_aspect)`. The profile is explicitly unavailable unless both a weighted
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palette and reliable Netto width/height-derived normalized geometry exist. Pixel dimensions never
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substitute for physical measurements.
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## Palette arpeggio
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`palette-arpeggio-v1` plays weighted palette entries in descending weight, with palette rank as a
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stable tie-break. Each color maps hue to pitch class and lightness to octave; its weight controls
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duration and velocity. The API includes the color, weight, note, MIDI number, frequency, duration,
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and pitch-source explanation for every step.
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These mappings are deliberately simple, explainable, and deterministic. They do not claim that an
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artwork has an inherent sound or that musical distance is visual similarity.
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