FA-77950 / Subtitle cue timing / Member archive
Cue snapping to video frame grid: end frame ceiling · case 05
Cues vanish one frame before the spoken line ends.
Case contract
For fps "N" or "N/D", frame k starts at k*1000*D/N ms. Each cue [start,end] (sorted) gets start frame floor(start*N/(1000*D)) and end frame ceil(end*N/(1000*D)), at least one frame long. A cue whose start frame precedes the previous cue end frame is pushed to that end frame (and kept at least one frame long). Output [a,b,ms(a),ms(b)] with ms(k)=floor(k*1000*D/N).
Why this case matters
Subtitle timing defects shift, hide or overlap captions that viewers depend on for comprehension and accessibility.
One recorded failure
Sample boundary fixtureThis sample comes from the broken implementation of a controlled reproducer.
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| regression: end frame ceiling | [[150, 152, 3000, 3040], [152, 153, 3040, 3060], [176, 177, 3520, 3540], [177, 178, 3540, 3560]] | [[150, 153, 3000, 3060], [153, 154, 3060, 3080], [176, 178, 3520, 3560], [178, 179, 3560, 3580]] | Failed |
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