A 200 ms overlap in an SRT file: what to check before shifting every subtitle

A subtitle file can parse successfully and still contain timing that deserves a second look. Two cues can overlap, a long line can flash too quickly, or one edit can leave a large gap.

This walkthrough uses the fictional sample shipped with ToryLab’s SRT Check & Shift. It explains file checks and a safe export sequence. It is not a client case study or evidence that a tool can judge a finished video.

Start with the exact overlap

The first sample cue ends at 00:00:03,000. The second starts at 00:00:02,800. Their overlap is 200 milliseconds:

1
00:00:01,000 --> 00:00:03,000
A small edit can improve a subtitle.

2
00:00:02,800 --> 00:00:04,500
This cue overlaps the previous one.

That overlap is a review flag, not proof of an error. Intentional simultaneous speech may need overlapping captions. Check the surrounding video and the delivery requirements before changing either cue.

A batch shift does not repair an overlap

Adding 500 milliseconds to every cue moves both cues equally. The same 200-millisecond overlap remains. Use a batch shift for a known global offset, then review individual start and end times separately.

The tool also flags cues that exceed its line-length or reading-speed settings and gaps over three seconds. These are review aids. They do not prove that subtitles are readable, synchronized, accurate or compliant with a particular broadcaster’s requirements.

Keep the original, then export a new file

1. Keep an unchanged copy of the original UTF-8 SRT.
2. Open the offline HTML tool in a desktop browser and import the file.
3. Review overlap, duration, gap and text-length flags. Compare with the actual video.
4. Apply a known batch offset, or edit the specific cue times that need correction.
5. Export a new SRT, reopen it, and check it beside the video at normal speed.

The tool blocks invalid durations and shifts that would move a cue before zero. It exports renumbered cues with millisecond timestamps. It does not transcribe audio, translate dialogue, burn subtitles into video or automatically synchronize captions.

Use the small offline tool

SRT Check & Shift is available for $3 on Gumroad. This is a ToryLab product link. The ZIP includes a single offline HTML tool, this three-cue sample, a start guide and a commercial-use license. No account or upload is required to use the downloaded tool.

The supported input is UTF-8 SRT, up to 2 MB and 10,000 cues. It is a desktop file-editing workflow. The sample and checks were authored and tested with AI assistance; the review of your actual video remains your responsibility.