Tempo ↔ Milliseconds Converter mechanism

Model scope

The implementation should document the note-value factor table and require BPM > 0. The empty honest_label is a concern: the user-facing label should explicitly state that BPM is quarter-note BPM and that note values are converted using factors relative to a quarter note.

• The formula is standard only when BPM means quarter-note beats per minute and noteValueFactor is explicitly defined relative to one quarter note.
• The spec does not define the allowed note values or their factors, so “any note value” is ambiguous.
• The spec does not state whether BPM must be a positive number or how invalid and zero BPM inputs are handled.

Units and conventions

• BPM is quarter-note beats per minute.
• 60000 is the number of milliseconds in one minute.
• noteValueFactor is dimensionless: quarter note = 1, half note = 2, whole note = 4, eighth note = 0.5, sixteenth note = 0.25, dotted quarter = 1.5, and so on.
• The output ms is milliseconds per specified note value.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "BPM": 120,
    "note_value": "quarter",
    "noteValueFactor": 1
  },
  "expected_outputs": {
    "ms": 500
  },
  "working": "60000 / 120 = 500 ms per quarter note; 500 × 1 = 500 ms."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The specification does not define input-domain rejection or note-value parsing. BPM = 0 is undefined, negative BPM yields an invalid negative duration, and the notation 1/4 can produce 125 ms or 2000 ms depending on convention.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json