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.
77 lines
3.4 KiB
Markdown
77 lines
3.4 KiB
Markdown
# Delta Spec: 808 Bass Sidechain Ducking
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## ADDED Requirements
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### Requirement: MIDI CC11 Event Data Model
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The schema MUST support an `CCEvent` dataclass with controller, time, and value fields, and `ClipDef` MUST accept an optional `midi_cc: list[CCEvent]` field defaulting to empty list.
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#### Scenario: CCEvent round-trips correctly
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- GIVEN `CCEvent(controller=11, time=0.5, value=50)`
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- WHEN serialized/deserialized via dataclass
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- THEN all fields preserved exactly
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#### Scenario: ClipDef with midi_cc
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- GIVEN a `ClipDef` with `midi_cc=[CCEvent(11, 0.0, 50), CCEvent(11, 0.18, 127)]`
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- WHEN clip is processed by builder
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- THEN builder sees `midi_cc` field and can iterate it
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### Requirement: Kick Position Cache
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A kick-cache dict `{drumloop_wav_path: list[beat_positions]}` SHALL be computed once per session, keyed by WAV path. `DrumLoopAnalyzer.transient_positions("kick")` MUST be the source, filtered by `confidence >= KICK_CONFIDENCE_THRESHOLD` (default 0.6).
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#### Scenario: Cache hit
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- GIVEN drumloop WAV already analyzed in same session
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- WHEN `build_bass_track()` requests kick positions for that path
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- THEN cached positions returned without re-analyzing WAV
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#### Scenario: Cache miss
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- GIVEN drumloop WAV not yet cached
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- WHEN kick positions requested
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- THEN `DrumLoopAnalyzer.analyze()` runs, positions cached by path key
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### Requirement: CC11 Ducking on Kick Hits
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For each kick transient position in the bass clip's time span, the system MUST emit CC11 events forming a ducking envelope: instantaneous drop to value 50 at kick time, hold at 50 for 0.02 beats, ramp to 127 by 0.18 beats after kick.
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#### Scenario: Single kick duck
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- GIVEN kick at beat 1.0 within a 4-beat bass clip
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- WHEN CC events generated
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- THEN emits `CCEvent(11, 1.0, 50)`, `CCEvent(11, 1.02, 50)`, `CCEvent(11, 1.18, 127)`
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#### Scenario: No kicks in clip
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- GIVEN drumloop with no kick transients in clip time range
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- THEN `midi_cc` is empty list — no CC events emitted
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## MODIFIED Requirements
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### Requirement: RPPBuilder MIDI Source Encoding
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`_build_midi_source()` MUST emit MIDI CC events as `E B0 0B xx` lines interleaved with note events, all sorted by absolute start time. Delta-encoding MUST continue for all E-lines.
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#### Scenario: CC events interleaved with notes
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- GIVEN clip with `midi_notes=[Note(60, 0.5, 1.0)]` and `midi_cc=[CCEvent(11, 0.0, 50)]`
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- WHEN `_build_midi_source()` called
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- THEN E-lines emitted in time order: CC at 0.0, Note at 0.5
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- AND CC line reads `E 0 B0 0B 32` (delta=0, CC11, value=50=0x32)
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#### Scenario: Delta sequencing across note+CC
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- GIVEN CC at 0.0, note at 0.5 beats
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- WHEN building E-lines
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- THEN CC delta = 0×960 = 0; note delta = 0.5×960 - 0 = 480
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- AND cursor reset correctly after CC event ticks
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### Requirement: Bass Track Generation
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`build_bass_track()` SHALL accept an optional `kick_cache: dict[str, list[float]]` parameter. When kick data is present for the drumloop used in each section, `midi_cc` events SHALL be generated and added to the bass `ClipDef`.
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#### Scenario: Bass clip with ducking CC
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- GIVEN kick cache has `[1.0, 2.5]` for drumloop, section covers beats 0-16
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- WHEN bass track built
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- THEN bass clip at that section has `midi_cc` with 2×3 CC events (one envelope per kick in range)
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- AND note generation unchanged from existing behavior
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#### Scenario: No kick cache provided
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- GIVEN `kick_cache` is `{}` or omitted
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- THEN `midi_cc` is empty — zero behavioral change from current output
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