VTT to SMI
Or paste subtitle text
What this conversion changes
1 thing is dropped or needs a decision
- Format-specific content
content the source format keeps outside its cues (non-cue blocks, header text, per-cue settings, commented-out events) — the target format has no place for it
This list comes from the capability matrix for these two formats, not from the particular file you loaded. A specific file may lose more if it uses features the format allows but the matrix does not model.
This page converts VTT to SMI. Drop a file in — or paste the text — and you get the SMI version back. The conversion runs entirely in your browser, so nothing is uploaded and no account is needed.
These two formats do not store the same things, and the difference is not cosmetic: format-specific content has nowhere to go in SMI. The list above comes from what the two formats can each express rather than from your file, so it is the same answer before you load anything.
One file is fine, and so is a whole season: the queue works through them in order and the results come down together as a single ZIP.
Examples
A typical VTT file, converted to SMI
Input
WEBVTT
intro
00:00:01.000 --> 00:00:04.000
Hello there.
00:00:04.500 --> 00:00:08.000 align:start position:10%
Second line with <i>italics</i>.
Output
<SAMI>
<HEAD>
<STYLE TYPE="text/css">
<!--
P { text-align: center; font-family: Arial, sans-serif; }
-->
</STYLE>
</HEAD>
<BODY>
<SYNC Start=1000>
<P>Hello there.
<SYNC Start=4000>
<P>
<SYNC Start=4500>
<P>Second line with <i>italics</i>.
<SYNC Start=8000>
<P>
</BODY>
</SAMI>
Dropped in this output: format-specific content. Everything else matches line for line.
The same conversion on an awkward input
Input
a stray comment line
cue-id-1
00:00:01.000 --> 00:00:02.000
No header, two lines before the timecode.
Output
<SAMI>
<HEAD>
<STYLE TYPE="text/css">
<!--
P { text-align: center; font-family: Arial, sans-serif; }
-->
</STYLE>
</HEAD>
<BODY>
<SYNC Start=1000>
<P>No header, two lines before the timecode.
<SYNC Start=2000>
<P>
</BODY>
</SAMI>
This is the kind of damage real files have — mixed line endings, stray whitespace, fields left empty. Compare it with the tidy example above to see what the parser forgives.
Frequently asked questions
What happens to VTT's NOTE, STYLE and REGION blocks in SMI?
They are dropped. A WebVTT file can carry a header, comments, a style block, region definitions and per-cue settings such as `align` or `position`, and SMI has nowhere to put them — it stores cues, not a document. The cues themselves, text and timings, come through whole.
What does the output look like when VTT becomes SMI?
Like SMI: no cue numbers and no timecode line: every cue is a `<SYNC Start=…>` tag with its text in a `<P>` under it, and — because a SYNC replaces whatever was on screen — a `<P> ` block just after it that puts the screen back to empty. Every VTT cue becomes one SMI cue, in the same order, with the same text.
Are the VTT timings exact in the SMI file?
Yes, to the millisecond — which is as fine as either format goes. VTT writes a moment as `00:00:04.126` and SMI writes the same moment as `Start=4126`; nothing is rounded or shifted between the two, and a cue that was on screen for 2.9 seconds still is.
How does a two-line VTT cue come out in SMI?
As two lines with a `<br>` between them, which is how SAMI writes a hard line break. The pairing survives — the two VTT lines still belong to one subtitle in the SMI output, and a player shows them together.
Do VTT cues keep their order in the SMI output?
Yes, and they are sorted by start time on the way — earliest first, which is how every format here expects them and how players read them. If your VTT file listed its cues out of sequence, the SMI output puts them back in order; that is a change to the file's structure rather than its content, and it is deliberate.
Can I convert the SMI back to VTT?
Yes, and it has its own list: converting SMI to VTT drops positioning and format-specific content. That list is different from the one above because the two formats keep different things.
Does the SMI output keep the VTT file's encoding?
No — the output is UTF-8, with Unix line endings and no byte-order mark, whatever the VTT file used. A file that arrives in UTF-16, or in a Windows single-byte encoding, is decoded on the way in (the result panel says so when that happens); what comes out is always the same UTF-8 SMI.