arpeggiate.py
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| 1 | """muse arpeggiate — convert simultaneous chord notes into a sequential arpeggio. |
| 2 | |
| 3 | Takes notes that overlap in time (chord voicings) and spreads them out |
| 4 | sequentially at a specified rhythmic rate. Agents that receive a chord-pad |
| 5 | track and want to convert it into a rolling arpeggio pattern can do this in |
| 6 | one command. |
| 7 | |
| 8 | Usage:: |
| 9 | |
| 10 | muse arpeggiate tracks/chords.mid --rate 16th |
| 11 | muse arpeggiate tracks/pads.mid --rate 8th --order up |
| 12 | muse arpeggiate tracks/piano.mid --rate 8th --order down |
| 13 | muse arpeggiate tracks/chords.mid --rate 16th --order random --seed 7 |
| 14 | muse arpeggiate tracks/chords.mid --rate 16th --dry-run |
| 15 | |
| 16 | Order values: up (low→high), down (high→low), up-down, random |
| 17 | |
| 18 | Output:: |
| 19 | |
| 20 | ✅ Arpeggiated tracks/chords.mid (16th-note rate, up order) |
| 21 | 12 chord clusters → 48 arpeggio notes |
| 22 | Run `muse status` to review, then `muse commit` |
| 23 | """ |
| 24 | |
| 25 | from __future__ import annotations |
| 26 | |
| 27 | import argparse |
| 28 | import logging |
| 29 | import pathlib |
| 30 | import random |
| 31 | import sys |
| 32 | |
| 33 | from muse.core.errors import ExitCode |
| 34 | from muse.core.validation import contain_path |
| 35 | from muse.core.repo import require_repo |
| 36 | from muse.plugins.midi._query import NoteInfo, load_track_from_workdir, notes_to_midi_bytes |
| 37 | |
| 38 | |
| 39 | type _FloatMap = dict[str, float] |
| 40 | logger = logging.getLogger(__name__) |
| 41 | |
| 42 | _RATE_FRACTIONS: _FloatMap = { |
| 43 | "quarter": 1.0, |
| 44 | "8th": 0.5, |
| 45 | "16th": 0.25, |
| 46 | "32nd": 0.125, |
| 47 | } |
| 48 | |
| 49 | _VALID_ORDERS = ("up", "down", "up-down", "random") |
| 50 | |
| 51 | |
| 52 | def _cluster_notes(notes: list[NoteInfo]) -> list[list[NoteInfo]]: |
| 53 | """Group notes into time-overlapping clusters (chords).""" |
| 54 | by_time = sorted(notes, key=lambda n: n.start_tick) |
| 55 | clusters: list[list[NoteInfo]] = [] |
| 56 | current: list[NoteInfo] = [] |
| 57 | window = max(n.ticks_per_beat // 8 for n in notes) if notes else 1 |
| 58 | |
| 59 | for note in by_time: |
| 60 | if current and note.start_tick > current[0].start_tick + window: |
| 61 | clusters.append(current) |
| 62 | current = [note] |
| 63 | else: |
| 64 | current.append(note) |
| 65 | if current: |
| 66 | clusters.append(current) |
| 67 | return clusters |
| 68 | |
| 69 | |
| 70 | def _order_cluster(cluster: list[NoteInfo], order: str, rng: random.Random) -> list[NoteInfo]: |
| 71 | s = sorted(cluster, key=lambda n: n.pitch) |
| 72 | if order == "up": |
| 73 | return s |
| 74 | if order == "down": |
| 75 | return list(reversed(s)) |
| 76 | if order == "up-down": |
| 77 | return s + list(reversed(s[1:-1])) |
| 78 | # random |
| 79 | shuffled = list(s) |
| 80 | rng.shuffle(shuffled) |
| 81 | return shuffled |
| 82 | |
| 83 | |
| 84 | def register(subparsers: "argparse._SubParsersAction[argparse.ArgumentParser]") -> None: |
| 85 | """Register the arpeggiate subcommand.""" |
| 86 | parser = subparsers.add_parser("arpeggiate", help="Spread chord voicings into a sequential arpeggio pattern.", description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter) |
| 87 | parser.add_argument("track", metavar="TRACK", help="Workspace-relative path to a .mid file.") |
| 88 | parser.add_argument("--rate", "-r", metavar="RATE", default="16th", help="Arpeggio note rate: quarter, 8th, 16th, 32nd.") |
| 89 | parser.add_argument("--order", "-o", metavar="ORDER", default="up", help="Arpeggio order: up, down, up-down, random.") |
| 90 | parser.add_argument("--seed", metavar="INT", type=int, default=None, help="Random seed (for --order random).") |
| 91 | parser.add_argument("--dry-run", "-n", action="store_true", help="Preview without writing.") |
| 92 | parser.set_defaults(func=run) |
| 93 | |
| 94 | |
| 95 | def run(args: argparse.Namespace) -> None: |
| 96 | """Spread chord voicings into a sequential arpeggio pattern. |
| 97 | |
| 98 | ``muse arpeggiate`` groups overlapping notes into chord clusters, then |
| 99 | replaces each cluster with an arpeggio — sequential notes at the specified |
| 100 | rhythmic rate in the specified pitch order. |
| 101 | |
| 102 | Durations are set to one grid step; original velocities are preserved. |
| 103 | Use ``--order up-down`` for a ping-pong arpeggio. |
| 104 | """ |
| 105 | track: str = args.track |
| 106 | rate: str = args.rate |
| 107 | order: str = args.order |
| 108 | seed: int | None = args.seed |
| 109 | dry_run: bool = args.dry_run |
| 110 | |
| 111 | if rate not in _RATE_FRACTIONS: |
| 112 | print(f"❌ Unknown rate '{rate}'. Valid: {', '.join(_RATE_FRACTIONS)}", file=sys.stderr) |
| 113 | raise SystemExit(ExitCode.USER_ERROR) |
| 114 | if order not in _VALID_ORDERS: |
| 115 | print(f"❌ Unknown order '{order}'. Valid: {', '.join(_VALID_ORDERS)}", file=sys.stderr) |
| 116 | raise SystemExit(ExitCode.USER_ERROR) |
| 117 | |
| 118 | root = require_repo() |
| 119 | result = load_track_from_workdir(root, track) |
| 120 | if result is None: |
| 121 | print(f"❌ Track '{track}' not found or not a valid MIDI file.", file=sys.stderr) |
| 122 | raise SystemExit(ExitCode.USER_ERROR) |
| 123 | |
| 124 | notes, tpb = result |
| 125 | if not notes: |
| 126 | print(f" (track '{track}' contains no notes — nothing to arpeggiate)") |
| 127 | return |
| 128 | |
| 129 | rng = random.Random(seed) |
| 130 | step = max(1, round(tpb * _RATE_FRACTIONS[rate])) |
| 131 | clusters = _cluster_notes(notes) |
| 132 | arpeggiated: list[NoteInfo] = [] |
| 133 | |
| 134 | for cluster in clusters: |
| 135 | ordered = _order_cluster(cluster, order, rng) |
| 136 | base_tick = ordered[0].start_tick |
| 137 | for i, note in enumerate(ordered): |
| 138 | arpeggiated.append(NoteInfo( |
| 139 | pitch=note.pitch, |
| 140 | velocity=note.velocity, |
| 141 | start_tick=base_tick + i * step, |
| 142 | duration_ticks=step, |
| 143 | channel=note.channel, |
| 144 | ticks_per_beat=note.ticks_per_beat, |
| 145 | )) |
| 146 | |
| 147 | if dry_run: |
| 148 | print(f"\n[dry-run] Would arpeggiate {track} ({rate}-note rate, {order} order)") |
| 149 | print(f" Chord clusters: {len(clusters)}") |
| 150 | print(f" Output notes: {len(arpeggiated)}") |
| 151 | print(" No changes written (--dry-run).") |
| 152 | return |
| 153 | |
| 154 | midi_bytes = notes_to_midi_bytes(arpeggiated, tpb) |
| 155 | workdir = root |
| 156 | try: |
| 157 | work_path = contain_path(workdir, track) |
| 158 | except ValueError as exc: |
| 159 | print(f"❌ Invalid track path: {exc}") |
| 160 | raise SystemExit(ExitCode.USER_ERROR) |
| 161 | work_path.parent.mkdir(parents=True, exist_ok=True) |
| 162 | work_path.write_bytes(midi_bytes) |
| 163 | |
| 164 | print(f"\n✅ Arpeggiated {track} ({rate}-note rate, {order} order)") |
| 165 | print(f" {len(clusters)} chord clusters → {len(arpeggiated)} arpeggio notes") |
| 166 | print(" Run `muse status` to review, then `muse commit`") |