SRT vs VTT vs ASS
Subtitle Formats Explained
Which subtitle format should you use? SRT for YouTube, VTT for web, ASS for professional editing. Here's everything you need to know — with syntax examples and compatibility charts.
| Feature | SRT | VTT | ASS |
|---|---|---|---|
| Full name | SubRip Text | Web Video Text Tracks | Advanced SubStation Alpha |
| Extension | .srt | .vtt | .ass |
| Complexity | Simple | Moderate | Advanced |
| Timestamps | ✓ (comma separator) | ✓ (period separator) | ✓ (centisecond) |
| Text styling | ✗ None | Basic (bold, italic) | ✓ Full (fonts, colours, effects) |
| Positioning | ✗ None | ✓ Cue positioning | ✓ Pixel-precise |
| Animations | ✗ None | ✗ None | ✓ Fade, move, rotate |
| YouTube | ✓ Supported | ✓ Supported | ✗ Not supported |
| HTML5 <track> | Partial | ✓ Native | ✗ Not supported |
| DaVinci Resolve | ✓ Import | Via conversion | ✓ Native |
| Premiere Pro | ✓ Import | Via conversion | Via conversion |
| VLC Player | ✓ | ✓ | ✓ |
| Vosuba export | ✓ Free | ✓ Free | ✓ Creator+ |
SRT — SubRip Text
The universal standard. Simple, portable, everywhere.
SRT is the most widely supported subtitle format in the world. It's a plain-text file with numbered segments, timestamps, and caption text. No styling, no positioning — just words and timing.
Syntax example
1 00:00:01,000 --> 00:00:04,500 Welcome to our tutorial on adding subtitles to video. 2 00:00:05,000 --> 00:00:08,200 We'll cover three different methods you can use today.
Compatible platforms
When to use SRT
Use SRT when you need maximum compatibility — uploading to YouTube, sharing with clients, or importing into any video editor. If you're unsure which format to use, SRT is always the safe choice.
VTT — Web Video Text Tracks
The web standard. Built for HTML5 video players.
VTT is the W3C standard for timed text on the web. It's similar to SRT but adds a header line, uses periods in timestamps, and supports basic styling (bold, italic) and positioning via CSS-like cue settings.
Syntax example
WEBVTT 1 00:00:01.000 --> 00:00:04.500 position:50% align:center Welcome to our tutorial on adding subtitles to video. 2 00:00:05.000 --> 00:00:08.200 We'll cover three different methods you can use today.
Compatible platforms
When to use VTT
Use VTT when embedding video on a website using the HTML5 <video> element. VTT is the only format natively supported by the <track> tag. It also works for LMS platforms like Moodle and Canvas.
ASS — Advanced SubStation Alpha
The professional format. Full creative control.
ASS is the most powerful subtitle format, offering pixel-precise positioning, custom fonts, colours, borders, shadows, and animations (fade, move, rotate). It's the standard for anime fansubbing and professional video post-production.
Syntax example
[Script Info] Title: My Subtitles ScriptType: v4.00+ [V4+ Styles] Format: Name, Fontname, Fontsize, PrimaryColour, ... Style: Default,Inter,48,&H00FFFFFF,&H00000000,... [Events] Format: Layer, Start, End, Style, Name, ... Dialogue: 0,0:00:01.00,0:00:04.50,Default,,Welcome to our tutorial.
Compatible platforms
When to use ASS
Use ASS when you need styled, animated captions for professional video editing. If you're burning captions into a video using FFmpeg or DaVinci Resolve, ASS gives you full control over the visual presentation. Not suitable for platform uploads (YouTube, Vimeo) — use SRT instead.
Quick decision guide
- Uploading to YouTube or social media? Use SRT.
- Embedding video on a website? Use VTT.
- Editing in DaVinci Resolve or Aegisub? Use ASS.
- Burning styled captions into a video? Use ASS (via Vosuba or FFmpeg).
- Sharing with a client who hasn't specified? Use SRT — it works everywhere.
- Need all three from one project? Use Vosuba — export SRT, VTT, and ASS from the same timeline.
Frequently asked questions
Which subtitle format is best for YouTube?
SRT is the best format for YouTube. It's universally supported, simple to edit, and YouTube accepts it natively via YouTube Studio. VTT also works but offers no advantage since YouTube ignores VTT styling. ASS is not supported by YouTube.
What is the difference between SRT and VTT?
SRT (SubRip Text) and VTT (Web Video Text Tracks) are both timed-text formats. The key differences: VTT uses a 'WEBVTT' header, uses periods instead of commas in timestamps, and supports positioning, styling, and cue identifiers. SRT is simpler — just sequence numbers, timestamps, and text. SRT has broader platform support; VTT is the standard for HTML5 web video.
When should I use ASS format?
Use ASS when you need full visual control over your subtitles — custom fonts, colours, positioning, animations, and effects. ASS is the standard for anime fansubbing, professional video editing in DaVinci Resolve, and any workflow where styled, pixel-precise captions are required. It is not supported by YouTube, Vimeo, or most social media platforms.
Can Vosuba export all three formats?
Yes. Vosuba exports SRT, VTT, and ASS from any project. The free tier includes unlimited SRT and VTT export. ASS export with styled captions is available on the Creator tier ($49 one-time).
Export SRT, VTT, and ASS from one project
Vosuba auto-transcribes your video and exports all three formats. Free SRT and VTT — unlimited, offline, no account.