Description
Subtract suppliedCaptionClockOffset from captionOnset, then subtract speechOnset for lag.
Caption timing compares text with a speech clock, while reading rate divides a supplied character count by display duration. Neither measurement alone establishes accessibility or comprehension.
Subtract suppliedCaptionClockOffset from captionOnset, then subtract speechOnset for lag.
When to use this tool
Use Caption Lead Lag Scalar when you need a caption lag or reading-rate term.
How to use the tool and how it works
- Enter captionOnset, speechOnset, suppliedCaptionClockOffset. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read lag, leads. Inspect leads before interpreting the associated values.
Subtract suppliedCaptionClockOffset from captionOnset, then subtract speechOnset for lag. Set leads when that adjusted caption onset is earlier than speech.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| captionOnset | Caption Onset | Required. Finite number. |
| speechOnset | Speech Onset | Required. Finite number. |
| suppliedCaptionClockOffset | Supplied Caption Clock Offset | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| lag | Lag | Required. Finite number. |
| leads | Leads | Required. Boolean. |
{
"input": {
"captionOnset": 12,
"speechOnset": 10,
"suppliedCaptionClockOffset": 1
},
"output": {
"lag": 1,
"leads": false
}
}Limitations and assumptions
- Use common time units and the stated offset sign; no waveform alignment, drift correction, or perceptual judgment is performed.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Review captions in context using the applicable accessibility and language-specific quality criteria.
References
Similar or alternative tools
- Caption Reading Rate Term
Divide nonnegative characters by positive durationSeconds for charactersPerSecond.
- Broadcast Cuehold Clock Gap
Add nonnegative heldSeconds to scheduled for revisedCue.