The SRT File Structure

By Ashley Poland

The native subtitle format for SubRip, SRT, is elegant in its simplicity. Every aspect of the subtitles are stored in a UTF-8 text-based SRT file. Very little formatting goes into SRT files; instead, the subtitle formatting is determined by the media player using them. While you can get programs especially for editing SRT files, the plain text nature of the format makes them easy to modify in any text editor.

Basic Layout

Subtitles within an SRT files are arranged in blocks that represent each frame the subtitles appear in. There are four elements to each block: the order of the subtitle, the time stamp and duration, the subtitle itself and a blank line to separate it from the next subtitle. For instance, the first two subtitles in a video could be:100:00:06,780 --> 00:00:07,790Who are you?200:00:07,825 --> 00:00:08,575I mean what are you?This specifies that the first subtitle starts almost seven seconds into the video, and lasts for barely over a second; the next one starts almost immediate afterwards. The SRT file continues like this; a full-length movie can easily have a couple thousand subtitles in sequence. For this reason, while you can edit subtitles using a text editor, creating them usually takes place in a specialized program.

Time Stamp and Duration

The time stamp above a subtitle is important; it tells your media player when to display the subtitle and for how long. The timing is precise, right down the millisecond. The basic format goes from the hour, to the minute, to the second, to the millisecond, or hh:mm:ss,zzz. The arrow implies duration, and the second time stamp denotes when the subtitle will stop displaying.


Your subtitle is entirely to discretion. It can be any language and contain as much text as you want -- of course, you don't want to contain more text than you do dialogue, or you pretty much defeat the purpose of subtitles. Each new line you create is displayed as a new line on the screen. The generally accepted format is one line for brief sentences and two short lines for long sentences. Use your best judgement; with screen resolution getting larger, people have screen space to spare, though not everyone watches videos in full screen mode.

Formatting and Symbols

While SRT subtitles are primarily text-based subtitles without formatting, you can use some basic HTML tags to give your subtitles depth. Most commonly used is the tag for italicizing text to represent that the speaker isn't on-screen, such as:191901:42:46,920 --> 01:42:48,220Here we go!You can also use the bold, underline and strike-through tags, or , and repsectively. You can also use the tag to make superficial font changes, but this might clash with an individual user's subtitle settings. If you want to include special characters, such as music notes (♫) to mark lyrics, you can -- but they may not display properly on every user's computer.