Caption timing drift after export from Premiere or DaVinci

The words are right but they arrive early or late after export. That usually means the caption file's timebase does not match the delivered video — not that the editor mis-heard the dialogue.

Why NLE exports drift

• Sequence start timecode. A sequence beginning at 01:00:00:00 shifts every cue unless the export includes that offset consistently.
• Frame rate mismatch. 23.976 vs 24 fps or 29.97 drop-frame vs non-drop-frame changes duration math over a long program.
• Re-linked or trimmed master. Captions authored on a rough cut, then delivered against a final trim without retiming.
• Wrong export format. Sidecar SRT from one timeline pasted onto a different render.

What to check in the NLE before export

1. Confirm sequence frame rate matches the deliverable master.
2. Export captions from the same timeline you are rendering for the client.
3. If the client player starts at zero, strip or normalize start offsets in the sidecar file.
4. Re-spot only after picture lock when possible — retiming is expensive.

After export: QA the sidecar

CaptionPass cannot invent missing sync against video, but it will normalize timestamps, trim overlaps, and flag reading-speed issues before upload. For deeper timecode theory see timecode and frame rate.