# SRT file

Canonical URL: https://getvidiyo.app/glossary/srt-file
Last updated: 2026-10-08

> Definition: An SRT (SubRip Subtitle) file is a plain-text file of numbered caption blocks, each with a start and end timecode and one or more lines of text, used to add closed captions or subtitles to a video.

An SRT file is the simplest common caption format there is: a text file that says "show these words from this time to that time". Because it's so simple, almost every video platform, player and editor reads it. If you need to hand captions to another tool or upload [closed captions](https://getvidiyo.app/glossary/open-vs-closed-captions) to YouTube, an SRT is the safe default.

## What does an SRT file look like?

An SRT file is a list of blocks, each with four parts: a sequence number, a timecode line, the caption text, and a blank line ([source](https://www.loc.gov/preservation/digital/formats/fdd/fdd000569.shtml)).

```
1
00:00:00,400 --> 00:00:02,100
We rebuilt the editor from scratch.

2
00:00:02,300 --> 00:00:04,800
Now you can cut a video
just by asking.
```

The rules that trip people up:

- Timecodes are `hours:minutes:seconds,milliseconds`, with a **comma** before the milliseconds.
- The arrow between times is two hyphens and a greater-than sign: `-->`.
- Each block ends with an empty line.
- Save it as plain UTF-8 text; YouTube requires UTF-8 for SRT files ([source](https://support.google.com/youtube/answer/2734698?hl=en)).

## Where does the SRT format come from?

The SRT format comes from SubRip, a program that extracted image-based subtitles from DVDs with optical character recognition and saved them as text. Its output format became the de facto standard, and the W3C's WebVTT format for web video was later based on it ([source](https://www.loc.gov/preservation/digital/formats/fdd/fdd000569.shtml)).

## How are SRT files used for YouTube, short-form and product videos?

SRT files are mainly used for closed captions and for moving captions between tools. On YouTube you upload one to add a caption track viewers can toggle and the platform can index. On a website, you convert it to WebVTT for the HTML player. For Reels and Shorts, most creators [burn captions in](https://getvidiyo.app/glossary/burned-in-captions) instead, since feeds handle caption files inconsistently, but an SRT is still useful as a transcript or for translation.

## SRT vs VTT: which should you use?

Use SRT for uploading to video platforms and exchanging captions between editors; use WebVTT for captions in your own HTML5 video player. The two are nearly identical: WebVTT adds a `WEBVTT` header, uses a period in timecodes and supports positioning and styling.

## How do you use SRT files in Vidiyo?

Vidiyo both reads and writes SRT files. In the Captions panel, the menu next to the actions has **Import SRT…** to bring captions in and **Export SRT…** to save your current captions, after you've generated them from the local transcript and corrected any words. You can also attach an SRT or VTT file in chat as reference, for example a script or a translation you want the assistant to follow.

## Frequently asked questions

### How do I open an SRT file?

Any text editor can open an SRT file, since it's plain text. Video players and editors read it as a caption track when it's loaded alongside the video or imported.

### Can an SRT file have styling?

Only a little. Some players read basic tags for bold, italic, underline and colour, but support varies, and YouTube ignores style markup in SRT files. For styled captions, burn them into the video.

### What is the difference between SRT and VTT?

WebVTT (.vtt) was based on SRT and is the web standard for HTML video. It uses a period instead of a comma in timecodes, starts with a WEBVTT header and supports positioning and styling.

## Related terms

- [Open vs closed captions](https://getvidiyo.app/glossary/open-vs-closed-captions)
- [Burned-in captions](https://getvidiyo.app/glossary/burned-in-captions)
- [Word-level captions](https://getvidiyo.app/glossary/word-level-captions)
- [Whisper transcription](https://getvidiyo.app/glossary/whisper-transcription)

## Where Vidiyo does this

- [Auto captions that are transcribed on your Mac](https://getvidiyo.app/features/auto-captions)

## Sources

- [SubRip Subtitle file format (Library of Congress)](https://www.loc.gov/preservation/digital/formats/fdd/fdd000569.shtml) (accessed 2026-10-08)
- [Supported subtitle and closed caption files (YouTube Help)](https://support.google.com/youtube/answer/2734698?hl=en) (accessed 2026-10-08)