When a title page offers the same language in two formats, people ask us which to take. The short answer: SRT if you just want words on a screen, ASS if it is anime or the uploader says the styling matters, VTT only if you are putting the subtitle on a web page. The long answer explains why, and it is worth two minutes because the wrong format is the second most common reason a subtitle "does not work".
SRT: the one that works everywhere
An SRT file is plain text. Each cue is a number, a start and end time, and the lines of text:
12
00:01:04,250 --> 00:01:07,100
I am become Death,
the destroyer of worlds.
Nothing else. No fonts, no colours beyond a little optional tagging, no positions. That poverty is its strength: every player, every television, every phone and every streaming box reads SRT. If you are unsure, download the SRT.
What SRT cannot do: put a sign translation at the top of the screen while dialogue runs at the bottom, or show two speakers in different colours. Players fake some of it with <i> and <b> tags, and a few honour a position tag, but do not count on it.
ASS and SSA: styling, positions, fonts
ASS (Advanced SubStation Alpha) is what anime fansub groups use, and what most of the anime subtitles on this site are. An ASS file carries styles: font, size, colour, outline, position on screen, timing for karaoke in the opening song, and signs placed over Japanese text on a shop front or a phone screen. When it is done well, a translated sign sits exactly where the original was and matches its look.
SSA is the older version of the same idea. Players that read ASS read SSA.
The catch is fonts. An ASS file names the fonts it wants, and if your player does not have them it substitutes something, so the careful layout can come out slightly wrong. Inside an MKV the fonts usually travel with the video. As a separate download they do not, which is why an anime subtitle can look different on your machine than in the group's screenshots. It still reads fine; it just loses some polish.
Which players handle ASS properly: MPV, VLC, PotPlayer, MX Player on Android, Kodi, Plex and Jellyfin. Televisions mostly do not, and the Windows built-in players do not. Convert to SRT for those.
VTT: the web's own
WebVTT is what browsers play through the <track> element, and what streaming services use behind the scenes. It looks like SRT with a header and a few extras (positioning, some styling). Download VTT only if you are building a web page or a web app that plays the video. For everything else, take the SRT; the content is the same and the support is wider.
SUB, IDX, SUP: pictures, not text
A few older uploads come as SUB with an IDX beside it (VobSub, ripped from a DVD) or as SUP (from a Blu-ray). These are images of the text, not text, so you cannot change the font, search them, or fix a typo. Players show them at a fixed size. We keep the ones that exist because sometimes they are the only subtitle for an old film, but the same file is often available as SRT from a later upload, so check the page.
There is also a text format also called SUB (MicroDVD), where timing is in frame numbers instead of seconds. Those only sync at the frame rate they were made for; SRT is safer.
What we do to every file
Every subtitle uploaded here is read, checked and stored twice: the original exactly as it came, and a cleaned copy in UTF-8 without a byte order mark, with line endings normalised. Downloads give you the cleaned copy by default and the original is one click away on the file's page. So the encoding problems that used to plague files from the old sites, the boxes and the question marks, are gone from anything that has passed through here.
Converting between them
- ASS to SRT: VLC can do it from the Convert dialog, Subtitle Edit does it in one click, and both drop the styling and keep the words and times. Signs and song lines are kept too, which can leave the top-of-screen translations sitting in the dialogue stream. It is readable, just busier.
- SRT to ASS: any converter; you gain nothing unless you then add styles yourself.
- SRT to VTT: change the header, swap the comma in the times for a full stop. Any converter, or a text editor if there are only a few cues.
So, which one?
- Film or series on a computer: SRT, unless an ASS is offered and the uploader notes styled signs.
- Anime: ASS, played in MPV or VLC. Take the SRT only for a television.
- Television or USB stick: SRT.
- Your own website: VTT.
- Old DVD films with nothing else: SUB/IDX will do until someone uploads text.
Each file's page says which format it is, how many lines it holds and whether it was made for the hearing impaired, so you can decide before you download.
