SRT to VTT Converter

Going the other way? Convert VTT back to SRT →

How do you convert SRT to VTT?

SRT to VTT adds a header line and changes one character per timestamp: the comma before the milliseconds becomes a full stop.

1. Paste the SubRip file above, or open it and copy it in. Each cue is an index line, a timing line, one or more text lines and a blank line.
2. Put the line WEBVTT and a blank line at the top of the output, because every WebVTT file opens with it.
3. Replace the comma before the milliseconds with a full stop in both timestamps of every cue.
4. Decide whether the index numbers come across as cue identifiers, then save the result as UTF-8 with a .vtt extension.

This page writes a WEBVTT header line, a blank line, then every cue with the comma in both timestamps replaced by a full stop.

SRT to VTT Conversion Table

Six parts of a subtitle file, and what happens to each one. Only one of them is a change to the text you can see. The timestamp difference between the two subtitle formats is one character: SubRip writes a comma before the milliseconds and WebVTT writes a full stop. 00:00:01,500 in SubRip is 00:00:01.500 in WebVTT.

A format is defined by what it can say. The rows below put the two halves of this conversion side by side, so the gap the conversion has to cross is a thing you can read rather than a thing you find out later. Every value in the table is the wording the defining document uses, not a summary of it, and a dash means the format has no answer to that row at all.

Worked Example: SRT to VTT

One cue, converted here at build time by the same code the box above runs. The working under it shows the timing line that went in, the decision taken, and the timing line that came out.

1
00:00:01,500 --> 00:00:04,000
Hello

WEBVTT

00:00:01.500 --> 00:00:04.000
Hello

The payload was not touched, and that is the whole point of this pair. WebVTT was built on SubRip. The W3C specification's acknowledgements name the SubRip program's SRT file format as the basis for the WebVTT text track format, which is why the two convert into each other so cleanly.

Subtitle files are timed text, not structured data. SubRip and WebVTT carry lines of prose against timestamps; they have no fields, no keys and no nesting, which is why they convert into each other and not into JSON. Nothing here has a field or a key to map, so the conversion is a header line and a punctuation mark.

The timestamp that went in is the one shape a SubRip file is allowed. A SubRip timestamp is written HH:MM:SS,mmm - two digits each for hours, minutes and seconds, then a comma and three digits of milliseconds. SubRip has no published specification and no registered media type, so this is the shape every player follows rather than a rule anyone wrote down.

Check it in reverse

Going back is the same edit in the other direction, and it is exact for a file this simple. The header line comes off, the cues are numbered from 1 in the order they appear, and the full stop before the thousandths becomes a comma again. A cue identifier that was not a number cannot survive that, because the SubRip convention is a sequential index and nothing else.

To prove nothing was lost, convert the VTT result back to SRT and compare it with the file you started from.

What This Conversion Cannot Carry

The direction that adds a header and drops a number is still lossy, and the converter says where. A WebVTT file must be encoded as UTF-8 and labelled text/vtt. A SubRip file declares no encoding at all, which is why accented characters in an SRT file can arrive as the wrong characters.

The SubRip side of every rule here

SubRip has no published specification and no registered media type. This converter matches the shape every player follows rather than implementing a standard, so the SubRip half of every rule here is convention.

The index numbers

The SubRip index numbers were dropped. DFCF19: WebVTT cue identifiers are optional, and where they appear each one must be unique — so an SRT to VTT conversion can drop them, and this one does.

The header line WebVTT requires

A WEBVTT line and a blank line were added at the front. DFCF18: every WebVTT file opens with the string WEBVTT and the specification requires two or more line terminators between that line and the rest of the file; a SubRip file has no header line, so converting to WebVTT means adding one.

The encoding the output needs

The output must be saved as UTF-8 and labelled text/vtt (FMT-webvtt-encoding). A SubRip file declares no encoding at all (FMT-subrip-encoding), which is why accented characters in an SRT file can arrive as the wrong characters.

Display coordinates after the end timestamp

Text followed the end timestamp ("X1:40"). SubRip files sometimes carry display coordinates there; nothing in WebVTT holds them, so they were dropped.

A cue with no index line

A cue arrived without an index line. FMT-subrip-cue-identifier records the convention as a sequential number on every cue, so one was supplied on the way out.

Each line above is written by the converter itself, and it appears under your own result whenever your document raises it. Nothing is dropped without one.

The sample above reverses exactly - write the same cues back out as SubRip .

What Else Changes Besides the Timestamps?

Whether the cue numbers come across

They are dropped by default and kept if you ask. WebVTT cue identifiers are optional, and where they appear the specification requires each one to be unique. SubRip numbers its cues in order by convention, so a VTT to SRT conversion adds the numbers and an SRT to VTT conversion can drop them.

What the timestamp is allowed to look like

WebVTT is looser than SubRip about the hours field, so a valid conversion has more than one correct form. A WebVTT timestamp is two-digit minutes, two-digit seconds, a full stop and three digits of thousandths, with the hours field optional and required only when the hours are not zero. Both 01:30.000 and 00:01:30.000 are valid WebVTT.

What the header line has to be

Exactly the string WEBVTT, followed by a blank line. Every WebVTT file opens with the string WEBVTT, and the W3C specification requires two or more line terminators between that line and the rest of the file. A SubRip file has no header line, so converting to WebVTT means adding one.

SRT to VTT in Code

The same conversion in two lines, one per language. Both add the header and rewrite the timestamps; neither drops the indexes. Neither line reports what the conversion could not carry; the converter above does.

Python: open("out.vtt","w").write("WEBVTT\n\n" + re.sub(r"(\d\d:\d\d:\d\d),", r"\1.", srt))

JavaScript: "WEBVTT\n\n" + srt.replace(/(\d\d:\d\d:\d\d),(\d\d\d)/g, "$1.$2")

Common Mistakes

• Leaving the comma in the timestamps. A player expecting WebVTT reads the timing line as malformed and shows no captions, with no error you can see.
• Saving the result as anything but UTF-8. A SubRip file declares no encoding, so an accented character can arrive wrong and stay wrong.
• Putting only one line break after WEBVTT. The specification asks for two or more, and a file with one is not WebVTT.

Frequently Asked Questions

Related Conversions

• If what you have is structured data rather than a subtitle file, pull the values out of JSON without the braces instead.
• If what you have is structured data rather than a subtitle file, flatten a JSON array into tab-separated columns instead.
• If what you have is structured data rather than a subtitle file, map JSON keys onto XML tags instead.
• If what you have is structured data rather than a subtitle file, write JSON out as a comma-separated file instead.
• If what you have is structured data rather than a subtitle file, read an XML document as JSON instead.
• If what you have is structured data rather than a subtitle file, read a CSV file as a JSON array of objects instead.

The rest of the family sits on the subtitle and data format index.