density.py
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| 1 | """muse density — note density analysis per bar for a MIDI track. |
| 2 | |
| 3 | Shows how many notes per beat fall in each bar, revealing texture changes: |
| 4 | sparse verses, dense choruses, quiet codas. A swarm of agents editing |
| 5 | different sections can use this to reason about arrangement density without |
| 6 | audio playback. |
| 7 | |
| 8 | Usage:: |
| 9 | |
| 10 | muse density tracks/piano.mid |
| 11 | muse density tracks/melody.mid --commit HEAD~4 |
| 12 | muse density tracks/rhythm.mid --json |
| 13 | |
| 14 | Output:: |
| 15 | |
| 16 | Note density: tracks/piano.mid — working tree |
| 17 | Bars: 16 · Peak: bar 9 (4.25 notes/beat) · Avg: 2.1 |
| 18 | |
| 19 | bar 1 ████████ 2.00 notes/beat ( 8 notes) |
| 20 | bar 2 ██████████████ 3.50 notes/beat (14 notes) |
| 21 | bar 3 ████ 1.00 notes/beat ( 4 notes) |
| 22 | ... |
| 23 | """ |
| 24 | |
| 25 | import argparse |
| 26 | import json |
| 27 | import logging |
| 28 | import pathlib |
| 29 | import sys |
| 30 | |
| 31 | from muse.core.errors import ExitCode |
| 32 | from muse.core.repo import require_repo |
| 33 | from muse.core.refs import read_current_branch |
| 34 | from muse.core.commits import resolve_commit_ref |
| 35 | from muse.plugins.midi._analysis import analyze_density |
| 36 | from muse.plugins.midi._query import load_track, load_track_from_workdir |
| 37 | |
| 38 | logger = logging.getLogger(__name__) |
| 39 | |
| 40 | _BAR_WIDTH = 32 |
| 41 | |
| 42 | def _read_branch(root: pathlib.Path) -> str: |
| 43 | return read_current_branch(root) |
| 44 | |
| 45 | def register(subparsers: "argparse._SubParsersAction[argparse.ArgumentParser]") -> None: |
| 46 | """Register the density subcommand.""" |
| 47 | parser = subparsers.add_parser("density", help="Show note density (notes per beat) per bar of a MIDI track.", description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter) |
| 48 | parser.add_argument("track", metavar="TRACK", help="Workspace-relative path to a .mid file.") |
| 49 | parser.add_argument("--commit", "-c", metavar="REF", default=None, dest="ref", help="Analyse a historical snapshot instead of the working tree.") |
| 50 | parser.add_argument("--json", action="store_true", dest="as_json", help="Emit results as JSON.") |
| 51 | parser.set_defaults(func=run) |
| 52 | |
| 53 | def run(args: argparse.Namespace) -> None: |
| 54 | """Show note density (notes per beat) per bar of a MIDI track. |
| 55 | |
| 56 | ``muse density`` reveals the textural arc of a composition: which bars are |
| 57 | dense, which are sparse. Agents orchestrating multi-part arrangements use |
| 58 | this to avoid over-crowding any single section, and to verify that section |
| 59 | transitions (verse → chorus) are properly contrast-shaped. |
| 60 | |
| 61 | Git cannot do this. Muse stores notes as structured data, so density is |
| 62 | computable at any historical snapshot with no manual inspection. |
| 63 | """ |
| 64 | track: str = args.track |
| 65 | ref: str | None = args.ref |
| 66 | as_json: bool = args.as_json |
| 67 | |
| 68 | root = require_repo() |
| 69 | commit_label = "working tree" |
| 70 | |
| 71 | if ref is not None: |
| 72 | branch = _read_branch(root) |
| 73 | commit = resolve_commit_ref(root, branch, ref) |
| 74 | if commit is None: |
| 75 | print(f"❌ Commit '{ref}' not found.", file=sys.stderr) |
| 76 | raise SystemExit(ExitCode.USER_ERROR) |
| 77 | result = load_track(root, commit.commit_id, track) |
| 78 | commit_label = commit.commit_id |
| 79 | else: |
| 80 | result = load_track_from_workdir(root, track) |
| 81 | |
| 82 | if result is None: |
| 83 | print(f"❌ Track '{track}' not found or not a valid MIDI file.", file=sys.stderr) |
| 84 | raise SystemExit(ExitCode.USER_ERROR) |
| 85 | |
| 86 | notes, _tpb = result |
| 87 | if not notes: |
| 88 | print(f" (no notes found in '{track}')") |
| 89 | return |
| 90 | |
| 91 | bars = analyze_density(notes) |
| 92 | |
| 93 | if as_json: |
| 94 | print(json.dumps( |
| 95 | {"track": track, "commit": commit_label, "bars": list(bars)}, |
| 96 | )) |
| 97 | return |
| 98 | |
| 99 | if not bars: |
| 100 | print(" (no bars detected)") |
| 101 | return |
| 102 | |
| 103 | peak_bar = max(bars, key=lambda b: b["notes_per_beat"]) |
| 104 | avg_npb = sum(b["notes_per_beat"] for b in bars) / len(bars) |
| 105 | |
| 106 | print(f"\nNote density: {track} — {commit_label}") |
| 107 | print( |
| 108 | f"Bars: {len(bars)} · " |
| 109 | f"Peak: bar {peak_bar['bar']} ({peak_bar['notes_per_beat']} notes/beat) · " |
| 110 | f"Avg: {avg_npb:.1f}" |
| 111 | ) |
| 112 | print("") |
| 113 | |
| 114 | max_npb = max(b["notes_per_beat"] for b in bars) or 1.0 |
| 115 | for b in bars: |
| 116 | fill = int(b["notes_per_beat"] / max_npb * _BAR_WIDTH) |
| 117 | print( |
| 118 | f" bar {b['bar']:>3} {'█' * fill:<{_BAR_WIDTH}}" |
| 119 | f" {b['notes_per_beat']:>5.2f} notes/beat" |
| 120 | f" ({b['note_count']:>3} notes)" |
| 121 | ) |