If every caption arrives late by the same amount, a constant shift is a useful fix. If the delay keeps growing, it isn't. Check more than the first line before deciding how to fix the file.
Subtitle Converter and Shifter works with SRT and VTT files. It can move every cue by an offset or map two reference cues to new start times for a linear drift correction. It doesn't transcribe the video.
Use a sample with an obvious timing marker
The six-second sample clip shows a white box and plays a tone at two seconds, then does the same at four seconds. The box and tone stand in for spoken lines, so the timing is easy to reproduce without a personal recording.
Load timing-late.srt into the converter and select the clip as Optional preview video. The first caption starts at 3.5 seconds and the second at 5.5 seconds. Both are 1.5 seconds later than their matching markers.
Set Shift all cues to -1.5 seconds, then select Save SRT. Open timing-late-converted.srt in a text editor. Its timing lines should now read:
00:00:02,000 --> 00:00:03,000
00:00:04,000 --> 00:00:05,000
The cue text doesn't change. That export is from Chromium 146 on Windows. There's also a correct reference file to compare. The preview video is muted, so use the white box there, or open the sample clip in a player with sound if you want to hear the tone.
Pick the sign that matches the problem
A positive offset moves captions later. A negative one moves them earlier. The control takes seconds, including fractions, from -30 to +30. Don't enter milliseconds there.
After shifting, check an early cue, a middle cue, and one near the end. If a cue moves before zero, its start is clipped to zero. If its adjusted end is no longer after its start, the cue is dropped. With a large negative offset, take an extra look at the beginning of the file.
SRT uses commas before milliseconds, and VTT uses periods and a WEBVTT header. Picking the other output format takes care of that. It doesn't keep every subtitle styling or layout feature, though. The parser keeps cue text and strips markup, so hang on to the original if formatting matters.
Use two references when the delay grows
Say a caption should start at 10 seconds but starts at 12, and a later caption should start at 100 but starts at 104. One constant offset can't fix both. In Fix drift, select those two cue numbers and enter their correct start times. Apply drift fix scales and shifts the cue timeline, then resets the constant offset.
Pick references far apart so you aren't fitting the whole video to two cues right next to each other. Check other cues afterward. A linear correction can help with a steady timing-rate difference, but it won't fix a missing scene, a different edit, or several sections with their own delays.
If you trimmed the video in Video Cutter, remember that the new clip has a different time origin. Subtitles timed for the full recording need to be adjusted to match it. Retiming captions before you've settled on the edit is a good way to create the same problem twice.
Decide whether captions should stay separate
A separate SRT or VTT can be switched off or replaced when the player supports it. Subtitle Burner draws the captions into an MP4 instead. Load the corrected subtitle file there, choose the font, size, position, outline, and background, then check the preview before selecting Burn subtitles.
Burning re-encodes the video and makes the lettering part of the picture. Turning a caption track off later won't remove those pixels. Get the timing right first, then check that the burned text is readable at the size people will see it. Keep the uncaptioned source and the corrected subtitle file so a later wording change doesn't mean starting from the burned copy.