Out-of-sync captions on YouTube look the same regardless of cause: the words appear too early or too late, and the gap often grows or shrinks across the video. Diagnosing the cause is more useful than blindly nudging — the right fix is different in each case.
Cause 1 — Frame rate mismatch
If your video was edited at 23.976 fps but exported as 24 fps (or vice versa), the caption SRT timed against one will drift against the other. Symptom: captions are perfectly in sync at second 0 and progressively shift as the video plays.
Fix: convert the SRT to the correct frame rate. SoCaptions' frame-rate converter tool handles 23.976 ↔ 24 ↔ 25 ↔ 29.97 ↔ 30 fps in one click. Re-upload the corrected SRT to YouTube Studio.
Cause 2 — YouTube upload-side audio padding
YouTube occasionally pads the start of an uploaded video by 100–500ms during ingest. Symptom: every caption is exactly the same fixed amount late, with no progressive drift.
Fix: shift the SRT by the offset. SoCaptions' shift-timing tool nudges every cue by the same amount. Test 200ms first, adjust as needed.
Cause 3 — Editor-side drift
Some editors (older Premiere builds, broken-frame-rate Final Cut renders) export SRTs based on timecode rather than runtime, and the result drifts on any video that uses drop-frame timecode. Symptom: drift compounds across the video, often jumping in chunks rather than smoothly.
Fix: re-export the SRT from a tool that bases output on actual elapsed time. Drop the video into SoCaptions and re-transcribe — the new SRT will be timed to runtime, not timecode.
If nothing works — re-transcribe
If you've tried frame rate, shift, and re-export and the captions are still off, re-transcribe the video from the source MP4 in a fresh tool. Whisper-based transcription against the same MP4 you uploaded to YouTube will produce a perfectly synced SRT 99% of the time.