Caption Cue Time Offset Applier
Shift caption times by an explicit signed millisecond offset, rejecting negative results and preserving cue text/IDs.
Description
Shift caption times by an explicit signed millisecond offset, rejecting negative results and preserving cue text/IDs.
A uniform cue offset preserves durations while shifting the full timeline. Negative resulting starts need explicit rejection.
When to use this tool
Shift caption times by an explicit signed millisecond offset, rejecting negative results and preserving cue text/IDs.
- Prepare the supplied cuesJson, offset 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 cuesJson, offset. 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.cues. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Require integer offset within plus or minus one trillion milliseconds and every shifted start nonnegative. Add it to both boundaries of every cue.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| cuesJson | JSON text, entered as one text field. The decoded structure is illustrated below; it is not a separate file. | Text |
| offset | offset. | Integer from -1e12 to 1e12 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": "cuesJson",
"decoded": [
{
"id": "a",
"start": 0,
"end": 4,
"text": "hi"
},
{
"id": "b",
"start": 3,
"end": 6,
"text": "hi"
}
]
}
]| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.cues | The cues list in the ordering and representation described above. |
{
"input": {
"cuesJson": "[{\"id\":\"a\",\"start\":0,\"end\":4,\"text\":\"hi\"},{\"id\":\"b\",\"start\":3,\"end\":6,\"text\":\"hi\"}]",
"offset": 2
},
"output": {
"result": {
"cues": [
{
"id": "a",
"start": 2,
"end": 6,
"text": "hi"
},
{
"id": "b",
"start": 5,
"end": 8,
"text": "hi"
}
]
}
}
}Limitations and assumptions
- No clipping, sorting, frame-rate adjustment or media-duration check occurs. Output remains subject to finite safe numeric bounds.
- Input cue records contain string id/text and integer millisecond start/end from zero to one trillion, with end at least start. At most 128 cue records are accepted; IDs need not be unique.
- 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
Use a subtitle-format parser or media review for markup, file syntax and synchronization. Preserve the integer-millisecond timeline and the stated overlap or clipping convention when composing these operations.
References
Similar or alternative tools
- Caption Cue Split at Time
Split cue intervals strictly containing an explicit time; duplicated text and IDs are intentional, not re-transcribed speech.
- Caption Cue Time Rational Scaler
Scale cue endpoints by a positive rational factor exactly; reject fractional milliseconds rather than inventing a rounding policy.