How this converter reads VobSub subtitles
VobSub subtitles contain images of text, they don't actually contain any text. When you watch a DVD, the player simply displays each image on screen. It doesn't need any fonts, and subtitles in any language or alphabet always display correctly.
To convert these images to plain text, you need OCR (optical character recognition). This converter does that with an AI language model.
Quality over speed
Reading every image with an AI model takes a little longer, but the results are worth it. When it's busy, your file may wait in a queue.
Full support for music notes
Music notes that mark singing or lyrics are recognized correctly. Extra care went into making sure they're read right wherever they appear: at the start or end of a line, two in a row, or around lyrics that run over two lines. Each one ends up in your srt file as ♪.
![Three subtitle pictures with music notes: ♪ Sue Storm commands the light ♪, ♪♪ [ Brass: Somber ], and lyrics over two lines with a note at the start and end](/images/ocr/music-notes.png)
Italic styling is kept
Subtitles use italics for a voice off screen, a narrator, lyrics or the title of a film.
This converter recognizes italic text and puts it between <i> tags in your srt file, so your video player shows it in italics too.
That works for whole lines, for one line of a dialogue, and for a single word or title in the middle of a sentence.
![Three subtitle pictures with italics: a dialogue whose second line is italic, a sentence with the film title Mars Attacks in italics, and an italic line under the label [woman 3]](/images/ocr/italics.png)
Multiple languages in one file
One sub/idx file can contain subtitles in several languages, and sometimes two in the same language: a normal one and one for the deaf and hard of hearing. The language of each subtitle is detected automatically, and the result page lists them all.
What are VobSub subtitles (.sub and .idx files)?
VobSub is the subtitle format of DVDs. On the disc itself, the subtitles are stored inside the .vob files. VobSub subtitles always come as a pair: a .sub file with the images, and an .idx file that says when to show each one. Both files are needed to convert to srt. In tools like MKVToolNix and MediaInfo, these subtitles show up as "VobSub".
Most sub/idx files come from a ripped DVD, often as a subtitle track inside an mkv file. To get the .sub and .idx files out of a video, use Extract Subtitles from Video, then convert them from VobSub to srt here.
VobSub vs srt subtitles
VobSub subtitles are images, so the files are big, the text can look blurry on a big screen, many devices and video players can't show them, and you can't edit the text. Srt subtitles are plain text: the files are small, they work in almost every player, and you can edit them in any text editor. Converting sub/idx to srt gives you subtitles that play anywhere and are easy to fix or change.