The Complete Guide to Subtitle Formats: SRT, VTT, ASS, and More
Which subtitle format to use for video editing, YouTube, and streaming. Export settings, format differences, and how to choose a format for common subtitle workflows.
Why Subtitles Matter
Subtitles serve three purposes: accessibility for deaf and hard-of-hearing viewers, better comprehension for non-native speakers, and stronger content signals for video platforms and site search.
Transcription is the hard part. Once you have the transcript, choosing the right subtitle format is mostly about knowing what each format does well.
Format Capability Matrix
| Format | Core Capability | Best Fit | Source Basis |
|---|---|---|---|
| SRT | Sequence numbers, timestamps, plain subtitle text | General uploads, video editors, long-term archives | SubRip text subtitle convention; simple structure and broad compatibility |
| VTT | WEBVTT header, cues, positioning, styling, comments, metadata | Web video, online courses, styled speaker labels | W3C WebVTT specification |
| ASS/SSA | Fonts, colors, positioning, layers, complex styling | Anime subtitles, complex on-screen text, precise layout | Advanced SubStation Alpha ecosystem and editors such as Aegisub |
| TXT/Markdown | Plain text or note-friendly transcript | Notes, excerpts, AI cleanup, reuse | General text formats; not full subtitle styling |
| JSON | Structured fields | Automation, QA, data analysis | Structured data exchange |
This table compares format capabilities, not every platform's upload policy. Always check the target platform's subtitle documentation before publishing.
The Big Three
SRT (SubRip)
The simplest and most widely supported format. A text file with sequential numbers, timestamps, and text blocks:
1
00:00:01,000 --> 00:00:04,000
Welcome to the show.
2
00:00:04,500 --> 00:00:08,200
Today we're talking about local transcription.
Best for: YouTube, Vimeo, Facebook, and most video players. If you're not sure which format to use, pick SRT.
Limitations: No styling (colors, fonts, positioning), no metadata. Pure text with timing.
VTT (WebVTT)
Built for the web. Supports styling via CSS and includes optional metadata headers.
WEBVTT
00:00:01.000 --> 00:00:04.000
<c.us_speaker>John:</c> Welcome to the show.
00:00:04.500 --> 00:00:08.200
<c.us_speaker>Alice:</c> Today's topic is local transcription.
Best for: HTML5 video players, online courses, and web-based video platforms.
Advantages over SRT: Speaker styling, color support, positioning cues, notes (non-displayed text for editors).
ASS/SSA (Advanced SubStation Alpha / SubStation Alpha)
Full-featured subtitle format from the anime fansub community. Supports complex styling, karaoke effects, and layered rendering.
Best for: Professional video production, anime subtitling, complex on-screen text (multiple speakers, pop-ups, animated text).
Trade-off: Steep learning curve. Editors like Aegisub make it manageable, but for most people, VTT's styling is enough.
When to Use What
| Use Case | Best Format | Why |
|---|---|---|
| YouTube upload | SRT | Simplest, universally supported |
| Web video with branding | VTT | Style support, web-native |
| Professional video editing | SRT or ASS | Most NLEs (Premiere, DaVinci) import SRT directly |
| Archiving | SRT | Simplest format, least chance of breakage |
| Multi-speaker content | VTT | Speaker labels with styling |
| Anime / complex text | ASS | Only format with full styling control |
Exporting from Audio Note
Audio Note supports multiple subtitle and text export formats, covering common workflows:
- SRT, VTT, ASS — the main three covered above
- LRC — enhanced lyric/sync format, used by some music players
- TXT — plain text, no timestamps
- Markdown — with timestamp links for note-taking apps
- JSON — for programmatic processing
- SUB / SBV / SMI — additional subtitle formats for specific players and platforms
Subtitle Timing Tips
Character Limit Per Line
Start with short lines and compact two-line blocks for English subtitles. Viewers read subtitles while watching the content, so long lines force them to choose between reading and watching. Tune the limit for the target platform, font size, and video aspect ratio.
Sync Adjustment
Audio Note's transcript timestamps are generated from transcription segments, which makes them a useful first pass rather than a frame-perfect edit decision list. If you're editing video in Premiere or DaVinci, spot-check the beginning, middle, and end, then shift or fine-tune cues where needed.
Line Breaks
Break subtitles at natural speech pauses — between sentences, after clauses, before conjunctions. Bad line breaks make subtitles harder to follow than no subtitles at all.
