Note Event Duration Scaler
Scale note durations by an explicit rational factor while preserving starts, pitch and channel; fractional ticks are allowed and not rounded.
Description
Scale note durations by an explicit rational factor while preserving starts, pitch and channel; fractional ticks are allowed and not rounded.
Scaling note durations can change articulation without moving note starts. Fractional duration results are allowed here.
When to use this tool
Scale note durations by an explicit rational factor while preserving starts, pitch and channel; fractional ticks are allowed and not rounded.
- Prepare the supplied eventsJson, numerator, denominator fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter eventsJson, numerator, denominator. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.events. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Parse standard note records, require numerator from 0 to one million and denominator from 1 to one million, then replace duration by duration*numerator/denominator.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| eventsJson | JSON text, entered as one text field. The decoded structure is illustrated below; it is not a separate file. | Text |
| numerator | numerator. | Integer from 0 to 1e6 inclusive |
| denominator | denominator. | Integer from 1 to 1e6 inclusive |
For the JSON text fields, the following decoded structures show the example records before they are serialized into input strings. Keep field names, list nesting and value types as shown.
[
{
"field": "eventsJson",
"decoded": [
{
"start": 1,
"duration": 3,
"pitch": 60,
"channel": 0
}
]
}
]| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.events | The events list in the ordering and representation described above. |
{
"input": {
"eventsJson": "[{\"start\":1,\"duration\":3,\"pitch\":60,\"channel\":0}]",
"numerator": 2,
"denominator": 1
},
"output": {
"result": {
"events": [
{
"start": 1,
"duration": 6,
"pitch": 60,
"channel": 0
}
]
}
}
}Limitations and assumptions
- Starts remain unchanged and zero scaling creates zero-duration events. Unlike exact caption rescaling, this operation can return fractional ticks and does not choose a rounding policy.
- Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
- Lists are limited to 128 entries. JSON text must meet bounded size and depth checks, and numeric outputs beyond the safe finite magnitude are rejected. Exact large integers use decimal strings.
- Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.
Alternative or Complementary methods
Retain the tick unit, channel numbering and event-pairing policy with the result. Use a MIDI-file parser or audio analysis when the task requires actual messages, playback behavior or recorded sound.
References
Similar or alternative tools
- dotted note duration calculator
Duration of a single-dotted note: one and a half times its undotted duration.
- grace note duration subtraction
Remaining duration of a main note when a grace note borrows a specified number of seconds from it.