Random Swing Timing Dataset Generator

Description

Generate synthetic paired-event timings from supplied ratios and tempos with delegated share and swing labels under caller tolerance.

A musical fixture expresses pitch or timing through explicit numeric conventions such as MIDI numbers, semitone intervals, beats, and durations. A reproducible symbolic sequence is separate from a performed sound or a judgment of musical quality.

Generate synthetic paired-event timings from supplied ratios and tempos with delegated share and swing labels under caller tolerance.

When to use this tool

Use this generator to create reproducible swing timing dataset cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.

How to use the tool and how it works

Supply count, ratios, tempoBpm, startMilliseconds, straightShareTolerance in the field shapes below. Set seed when you need an explicit replay.
Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
Read pairs. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.

Draw an integer BPM and a supplied positive first/second timing ratio. Convert BPM to milliseconds per beat, normalize the ratio into two subdivisions, and accumulate their onset and ending times. A delegated swing classification uses the requested straightTolerance.^[1]

Delegated operations used for this result: bpm to ms; swing ratio percentage classifier. Their calculation or parsing conventions apply to the corresponding result fields.^{[2, 3]}

Input field	Meaning and units	Accepted input
count	Requested count; the mechanics explain whether one draw expands into several returned records.	Required. Safe integer; minimum 1; maximum 128.
ratios	Ratios	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32.
ratios[].first	First	Required. Finite number; strictly above 0.
ratios[].second	Second	Required. Finite number; strictly above 0.
tempoBpm	Tempo Bpm	Required. Object; no unknown keys.
tempoBpm.minimum	Minimum	Required. Safe integer; minimum 1.
tempoBpm.maximum	Maximum	Required. Safe integer; minimum 1.
startMilliseconds	Start Milliseconds	Required. Finite number.
straightShareTolerance	Straight Share Tolerance	Required. Finite number; minimum 0; strictly below 0.5.
seed	Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed.	Optional. Safe integer.

Output field	Interpretation	Returned shape
pairs	Pairs	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 128.
pairs[].index	Index	Required. Safe integer; minimum 0; maximum 127.
pairs[].ratioFirst	Ratio First	Required. Finite number; strictly above 0.
pairs[].ratioSecond	Ratio Second	Required. Finite number; strictly above 0.
pairs[].beatsPerMinute	Beats Per Minute	Required. Finite number; strictly above 0.
pairs[].beatMilliseconds	Beat Milliseconds	Required. Finite number; strictly above 0.
pairs[].firstOnsetMilliseconds	First Onset Milliseconds	Required. Finite number.
pairs[].secondOnsetMilliseconds	Second Onset Milliseconds	Required. Finite number.
pairs[].endMilliseconds	End Milliseconds	Required. Finite number.
pairs[].firstDurationMilliseconds	First Duration Milliseconds	Required. Finite number; strictly above 0.
pairs[].secondDurationMilliseconds	Second Duration Milliseconds	Required. Finite number; strictly above 0.
pairs[].firstSubdivisionSharePercent	First Subdivision Share Percent	Required. Finite number.
pairs[].longToShortSubdivisionRatio	Long To Short Subdivision Ratio	Required. Finite number; strictly above 0.
pairs[].swingTimingClass	Swing Timing Class	Required. Text.
randomness	Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source.	Required. Object; no unknown keys.
randomness.seed	Optional numeric replay seed; normalization and precedence are explained below.	Required. Safe integer. or Null.
randomness.source	Source	Required. Text; one of "context", "seed".

An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.

json

{
  "input": {
    "count": 2,
    "ratios": [
      {
        "first": 1,
        "second": 1
      },
      {
        "first": 2,
        "second": 1
      },
      {
        "first": 1,
        "second": 2
      }
    ],
    "tempoBpm": {
      "minimum": 120,
      "maximum": 120
    },
    "startMilliseconds": 0,
    "straightShareTolerance": 0.01,
    "seed": 42
  },
  "output": {
    "pairs": [
      {
        "index": 0,
        "ratioFirst": 2,
        "ratioSecond": 1,
        "beatsPerMinute": 120,
        "beatMilliseconds": 500,
        "firstOnsetMilliseconds": 0,
        "secondOnsetMilliseconds": 333.3333333333333,
        "endMilliseconds": 500,
        "firstDurationMilliseconds": 333.3333333333333,
        "secondDurationMilliseconds": 166.66666666666666,
        "firstSubdivisionSharePercent": 66.66666666666666,
        "longToShortSubdivisionRatio": 2,
        "swingTimingClass": "long-short-swing"
      },
      {
        "index": 1,
        "ratioFirst": 1,
        "ratioSecond": 2,
        "beatsPerMinute": 120,
        "beatMilliseconds": 500,
        "firstOnsetMilliseconds": 500,
        "secondOnsetMilliseconds": 666.6666666666666,
        "endMilliseconds": 1000,
        "firstDurationMilliseconds": 166.66666666666666,
        "secondDurationMilliseconds": 333.3333333333333,
        "firstSubdivisionSharePercent": 33.33333333333333,
        "longToShortSubdivisionRatio": 0.5,
        "swingTimingClass": "reverse-short-long"
      }
    ],
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

Ratios describe a nominal timing grid, not performed groove or perceptual swing. BPM bounds must be ordered and accumulated times must remain numerically representable.
A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.

Alternative or Complementary methods

For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.

References

Tool behavior and example: Random Swing Timing Dataset Generator — tool.io
Calculation or validation: music/bpm-to-ms — tool.io
Calculation or validation: music/swing-ratio-percentage-classifier — tool.io

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