014e636889
- section-energy: track activity matrix + volume/velocity multipliers per section - smart-chords: ChordEngine with voice leading, inversions, 4 emotion modes - hook-melody: melody engine with hook/stabs/smooth styles, call-and-response - mix-calibration: Calibrator module (LUFS volumes, HPF/LPF, stereo, sends, master) - transitions-fx: FX track with risers/impacts/sweeps at section boundaries - sidechain: MIDI CC11 bass ducking on kick hits via DrumLoopAnalyzer - presets-pack: role-aware plugin presets (Serum/Decapitator/Omnisphere per role) Full SDD pipeline (propose→spec→design→tasks→apply→verify) for all 7 changes. 302/302 tests passing.
96 lines
2.8 KiB
Markdown
96 lines
2.8 KiB
Markdown
# Transition FX Specification
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## Purpose
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Glue sections together by placing audio FX clips at arrangement boundaries using existing `role="fx"` library samples.
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## Requirements
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### Requirement: FX Track Existence
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The system MUST create a dedicated "Transition FX" audio track with clips at 7 section boundaries.
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#### Scenario: FX track present in arrangement
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- GIVEN a 9-section song
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- WHEN `compose.py` runs
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- THEN a track named "Transition FX" exists with 7+ audio clips at boundary positions
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### Requirement: Riser Before Climax
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A riser/wash FX MUST start 2–4 beats before build→chorus and bridge→final boundaries, ending ON the boundary downbeat.
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#### Scenario: Riser before chorus
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- GIVEN build ends at beat 64 (bar 16)
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- WHEN FX is built
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- THEN a riser at position 60 (beat 60), length 4, `fade_in` ≥ 1.0s
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#### Scenario: Riser before final
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- GIVEN bridge ends at beat 176 (bar 44)
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- WHEN FX is built
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- THEN a riser at position 172, length 4, `fade_in` ≥ 1.0s
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#### Scenario: Riser before chorus2
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- GIVEN verse2 ends at beat 128 (bar 32)
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- WHEN FX is built
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- THEN a riser at position 124, length 4, `fade_in` ≥ 1.0s
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### Requirement: Impact on Section Downbeat
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An impact/stab FX MUST start on beat 1 of CHORUS (beat 64) and FINAL (beat 176).
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#### Scenario: Impact on chorus beat 1
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- GIVEN chorus starts at beat 64
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- WHEN FX is built
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- THEN an impact clip at position 64, length 1–2 beats, `fade_out` ≥ 0.2s
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#### Scenario: Impact on final beat 1
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- GIVEN final starts at beat 176
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- WHEN FX is built
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- THEN an impact clip at position 176, length 1–2 beats
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### Requirement: Transition Sweeps Between Verses
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Short transition FX MUST bridge chorus→verse2 (beat 96) and chorus2→bridge (beat 160).
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#### Scenario: Sweep bridges chorus to verse2
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- GIVEN chorus ends at beat 96
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- WHEN FX is built
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- THEN a transition clip at position 94, length 2 beats, `fade_in` and `fade_out` > 0
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### Requirement: FX Sample Selection
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The system SHALL select FX samples via `SampleSelector.select_one(role="fx")`, favoring short samples for impacts, long for risers.
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#### Scenario: FX role returns candidates
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- GIVEN 57 FX samples in library with ATONAL_ROLES including "fx"
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- WHEN `select(role="fx")` is called
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- THEN non-empty result returned; key scoring skipped (neutral 0.5)
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### Requirement: Fade Curves
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FX clips MUST use `fade_in`/`fade_out`. Risers: `fade_in` ≥ 0.3s. Impacts: `fade_out` ≥ 0.2s.
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#### Scenario: Riser fades in, impact fades out
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- GIVEN riser and impact clips defined
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- WHEN ClipDef is created
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- THEN riser.fade_in > 0 AND impact.fade_out > 0
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### Requirement: FX Track Mixing
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The FX track SHALL have volume ≤ 0.80 and send to Reverb/Delay returns.
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#### Scenario: FX track has moderate volume and sends
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- GIVEN "Transition FX" track created
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- WHEN track is defined
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- THEN volume = 0.72, send_level includes reverb (0.08) and delay (0.05)
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