File formats
VTT vs SRT: which subtitle format should you use?
Choose the subtitle format accepted by your destination. SRT is a useful interchange format when an editor requests SubRip. VTT is the format used for HTML video text tracks. Both can carry timed words; converting between them does not translate the words or improve transcription accuracy.
VTT and SRT at a glance
These are the differences you will notice when opening a basic subtitle file in a text editor.
| Feature | VTT / WebVTT | SRT / SubRip |
|---|---|---|
| Extension | .vtt | .srt |
| File header | WEBVTT | No equivalent header |
| Milliseconds | 00:00:01.500 | 00:00:01,500 |
| Cue labels | Optional identifiers | Usually numbered |
| Typical destination | HTML video text tracks | Editors and players accepting SRT |
For an HTML video player, use WebVTT
An HTML track element attaches a WebVTT caption or subtitle file to a video. This example assumes that the video and English caption file are served from the same website. Test caption selection in the actual player after publishing; a successful conversion alone does not confirm the hosting setup.
<video controls src="workshop.mp4">
<track kind="captions" src="workshop.vtt"
srclang="en" label="English" default />
</video>What changes when you convert subtitle formats?
SubtitleDock changes the file structure while retaining words and start/end times. VTT to SRT adds cue numbers and converts timestamp punctuation. SRT to VTT adds the WEBVTT header. The converter removes styling, positioning and format-specific annotations, showing notes when information is removed.
Keep the source file if its presentation matters. Preview the converted file in the destination player to check line wrapping and placement. A player may display the same words differently even when the timecodes match.
Avoid these format-conversion mistakes
Changing the filename extension is not a conversion. It leaves the header and timecode syntax unchanged. Likewise, converting an out-of-sync SRT to VTT carries the same delay into the new file.
If your goal is a readable transcript, choose TXT instead of either timed format. If your only input is a video, generate subtitles first. Matching the task to the tool avoids unnecessary conversions and makes it easier to keep track of the original.