Subtitle Editor

What Subtitle Editor helps you do

Edit SRT and VTT subtitle files in a table instead of a text editor. Change cue timing, add or remove cues, shift the whole file by a fixed number of seconds, preview against a video and export a clean file. It is the repair step before burning captions or uploading a caption track to a platform.

Subtitle parsing, editing and export run in your browser. Caption files and preview videos are never uploaded to Haivix.

How it works

The file is parsed into cues with start and end times. Each row is editable, and the summary counts timing problems such as reversed ranges or overlaps. A global shift applies the same offset to every cue, clamping negative results so the first cue never starts before zero. The optional video preview seeks to a cue when you click its number, which is the quickest way to confirm a fix without rendering the whole video.

How to use Subtitle Editor

1. Load an SRT or VTT file, or paste the cue text.
2. Fix the wording and the start and end times in the table.
3. Use the shift control when the whole file is offset.
4. Add or delete cues as needed.
5. Drop in a video and preview the active cue.
6. Download the cleaned SRT or VTT file.

When to use it

• Correct captions that drift a few seconds out of sync.
• Fix overlapping or reversed cue timings before upload.
• Merge or split cues after an edit changed the pacing.
• Translate a caption file while keeping the original timings.
• Check captions against the video before burning them in.
• Clean a caption file before uploading it to a platform.
• Fix caption line breaks before publishing.

When not to use it

• Do not use it to burn captions into the picture; the subtitle burn-in tool does that.
• Do not expect automatic transcription; the editor works from an existing file.
• Do not use it for formats other than SRT and VTT.

Example

A caption file for a 30-minute talk is consistently 2.5 seconds late. A single negative shift of 2.5 seconds moves every cue at once, the timing warnings clear, and the file is exported as VTT for the platform that requires it.

What you can do with Subtitle Editor

• Edit start and end times per cue.
• Add, delete and reorder cues.
• Shift the whole file by a positive or negative offset.
• Highlight invalid or overlapping ranges.
• Preview cues against a local video.
• Import and export SRT or VTT.
• Sort cues by start time after an edit.

Example workflow

Edit the file here, then burn it with the subtitle tool or upload it as a caption track. Keeping the editing and the rendering separate means a timing fix does not require another video encode.

Save a copy of the exported file with the video. It is the source for future translations and for platforms that accept a caption track instead of burned-in text.

When two languages share the same timing, duplicate the file, replace the text and keep the cue numbers identical. That makes it easy to switch tracks without re-checking every offset.

What to know before you start

• Only SRT and VTT are supported.
• The preview shows the active cue below the player, not styled captions over the video.
• There is no automatic speech recognition.
• Very large files can be slow to render in the table.
• Styling beyond the cue text is not preserved on export.
• The editor does not translate captions automatically.

Common mistakes

• Shifting the whole file when only the first few cues are wrong.
• Leaving overlapping cues that hide each other during playback.
• Editing a copy and exporting the original by mistake.
• Assuming the preview applies the platform's final caption styling.
• Changing the text but leaving the end time when a long cue is split into two.

Troubleshooting

If a cue does not appear in the preview, its time range may be reversed or outside the video duration. The warning summary points at the row.

If a negative shift clips the first cue, the editor clamps it at zero. Compare the result before exporting.

If the exported file is rejected, check that the extension matches the format and that the timing uses the separator the platform expects.

If timing warnings remain after an edit, look for a cue with the same start and end time. A zero-length cue cannot display, even when its text is correct.

Related standards and documentation

• The W3C WebVTT specification defines cue timing and syntax for VTT.
• SRT is a de facto format with comma-separated milliseconds in the timing line.