SRT, VTT or ASS: which subtitle file should you export?

A transcript becomes useful when it leaves the app. The export format decides where it can go: an editor, a web player, a streaming overlay, or a plain note. Here is the short version, then the details.

SRT: the safe default

SubRip (.srt) is the most widely accepted subtitle format. Every video editor, most players, YouTube, and most subtitle tools read it.

The structure is simple: a number, a timecode range, and the text. Timecodes use commas for milliseconds.

1
00:00:02,000 --> 00:00:04,500
Hola a todos.
Hello everyone.

SRT has no styling, no positioning, and no language metadata. That is exactly why it travels well. If you only export one format, export SRT.

WebVTT: the web player format

WebVTT (.vtt) is what HTML5 <track> elements expect. It supports cue identifiers, basic styling, positioning, and metadata.

The differences that bite people are small:

• The file must start with WEBVTT.
• Timecodes use dots, not commas: 00:00:02.000 --> 00:00:04.500.
• Blank lines separate cues.

If you are publishing to a web player, VTT is the right choice. If you are sending subtitles to a video editor, SRT is usually easier.

ASS: styling and overlays

Advanced SubStation Alpha (.ass) is used by OBS, Aegisub, and anime fansub workflows. It has a header with styles, fonts, colours, positioning, and dialogue lines with per-line overrides.

Use ASS when you need:

• a fixed on-screen style for a stream overlay;
• karaoke or per-word effects;
• positioning that platforms like OBS will honour.

Most people do not need ASS. It is powerful and easy to break: one wrong header and players silently ignore the file.

Bilingual subtitles

Bilingual output is just two lines per cue: the original above, the translation below. All three formats support it.

1
00:00:02,000 --> 00:00:04,500
Hola a todos.
Hello everyone.

Some players shrink line spacing when a cue has two lines. If readability matters, export single-language subtitles and keep the bilingual version for editing.

What TanLens exports

From a saved transcript you can export:

• SRT — for YouTube, editors, and general use.
• VTT — for HTML5 players.
• ASS — for OBS and styled playback.
• TXT — when you only need the text.

Bilingual export keeps the original and translation lines; single-language export keeps your choice. Timecodes come from the caption segments, so fixing a misheard sentence does not shift the rest of the file.

A workflow that works

1. Save the transcript at the end of the session.
2. Fix names and numbers in the segment editor; apply a glossary for recurring terms.
3. Export SRT for the editor and VTT for the web player.
4. Keep the transcript as the source of truth; regenerate subtitles after edits instead of patching files by hand.

The format is boring, and that is the point: the words are the product.