SubRip
The simplest subtitle format there is, and the one almost everything plays: numbered blocks of text, each with a start and an end time. No styling to speak of, no positioning, no header. That is why it is everywhere.
At a glance
| Extension | .srt |
|---|---|
| Media type | application/x-subrip (unregistered) |
| Specification | None. Defined by what players accept. |
| Time precision | Milliseconds |
| Text encoding | Not declared in the file. UTF-8 is the safe choice; Subtitld detects older encodings when it opens one. |
| Styling | Italic, bold, underline and colour, through unofficial tags |
| Positioning | None in the format |
| In containers | Matroska as S_TEXT/UTF8; converted to mov_text for MP4 |
Anatomy of a subtitle
A file is a list of blocks. Each block has four parts, always in this order.
3 00:00:27,000 --> 00:00:30,500 ...you have your robotics, and I just want to be awesome in space.
- 1 · Counter
A number, starting at 1. Required, though most players ignore it.
- 2 · Timing
Start, the arrow
-->, end. Spaces around the arrow. - 3 · Text
One or more lines. Two is the usual limit for reading.
- 4 · Blank line
Ends the block. Without it, the next counter becomes text.
The timecode
A comma, not a period. 00:00:27.000 is WebVTT's way of writing it. Some players forgive the period; strict readers, Subtitld's among them, refuse the file. It is the most common reason an SRT "won't open".
Formatting tags
None of these are part of a standard, but players have agreed on them over the years. Use them sparingly; not every platform shows them.
| Tag | Effect | Support |
|---|---|---|
<i>…</i> |
Italic, for voices off screen | Almost everywhere |
<b>…</b> |
Bold | Most desktop players |
<u>…</u> |
Underline | Most desktop players |
<font color="#ff0"> |
Text colour | Desktop players; often ignored online |
{\an8} |
Move to the top, borrowed from SubStation Alpha | VLC, mpv and others |
SRT in Subtitld
- Every subtitle's text and line breaks
- Start and end, to the millisecond
- The order of subtitles
- Speakers, their faces and colours
- Translations kept beside the original
- Dubs and metadata
Save a .usfx project to keep them.
SRT or WebVTT?
| SubRip .srt | WebVTT .vtt | |
|---|---|---|
| First line | The first counter | WEBVTT |
| Milliseconds | After a comma | After a period |
| Counter | Required | Optional cue name |
| Position | — | Cue settings: line, position, align |
| Styling | Unofficial tags | CSS through ::cue |
| In web browsers | Needs converting | Native, with <track> |
| Pick it for | Players, editors, uploads | Video on the web |
Trivia
The format is named after SubRip, a Windows program that read the subtitles off DVDs with OCR and wrote them out as text.
WebVTT began life under that name, as SubRip adapted for the web, before it grew a header, cue settings and CSS.
No body ever published a specification. The comma, the arrow and the blank line are a convention that held for a quarter of a century.
Open it in Subtitld with the video and retime it on the waveform.