How to open a subtitle file online
Three steps, a few seconds, no software.
Open your .ASS file
Drop it on the box, choose it from your device, or paste its text straight in.
View every line
See the start, end, duration and reading speed of each line, with any problems flagged.
Preview, fix, convert
Play the lines over your video, shift the timing, then download in the format you need.
What is a .ASS file?
Timed text that appears on top of a video.
An ASS file is an Advanced SubStation Alpha subtitle file - plain text that holds timed subtitle lines plus fonts, colors, positioning, and effects. To watch it, place the .ass next to your video with the same base name (movie.mkv + movie.ass) and a player like MPV or VLC loads it automatically. To edit it, use Aegisub or Subtitle Edit.
Programs that open .ASS files
| Full name | Advanced SubStation Alpha Subtitle |
|---|---|
| Developer | Community format (evolved from SubStation Alpha by Kotus); popularized by the Aegisub editor |
| First released | Advanced SubStation Alpha (ASS) early 2000s, extending SubStation Alpha (SSA, 1998) |
| Category | Text & Code |
| MIME type | text/x-ssa |
Related viewers
Every viewer is free to use.
Frequently asked questions
Is my .ASS file uploaded?
No. The file is read by your browser. If you preview with a video, the video is also played locally.
My .ASS file is out of sync. Can I fix it?
Yes. If they're early or late by a fixed amount, enter the difference in milliseconds and click Shift. If they drift more and more over time, the frame rate is wrong: use Change FPS (for example 25 → 23.976).
Why are some characters broken (é, ł)?
Older subtitles are often saved in a regional encoding like Windows-1250. We detect it automatically and every download is saved as UTF-8, which works everywhere.
What do the warnings mean?
Overlap: two lines on screen at once. Too fast: more than 20 characters per second. Too short: under 0.83 s. Long line: over 42 characters. 3+ lines: too much text at once.
Can I convert ASS to SRT?
Yes. Italic, bold and underline are kept; positioning and karaoke effects are dropped because SRT can't store them.
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