What is an SRT file and how to use it

What is inside

An SRT file (SubRip text) is a list of entries. Each entry has four parts: a number, a time range, one or two lines of text, and a blank line before the next entry.

1
00:00:01,200 --> 00:00:03,800
Welcome to the studio.

2
00:00:04,000 --> 00:00:06,500
Today we are recording
the Spanish version.

The time is hours, minutes, seconds and milliseconds, with a comma before the milliseconds. That is the whole format.

Why it became the default

It is readable by people and by software. Any editor can open it, a translator can work in it without special tools, and nearly every player, social platform and video host accepts it. When a platform does not state a format, an SRT is the safest thing to send.

What an SRT cannot do

• No styling you can rely on. Colour, italics and position are handled differently by each player, so do not count on them.
• No metadata. The file does not say which language it is in. The file name has to, so name it clearly, for example launch-film_de.srt.
• No speaker labels or sound descriptions by design. You can type them into the text, which is how captions are often delivered, but the format does not understand them.

When a platform asks for a richer format, such as VTT or a broadcast format, the same text is exported again. Keep one clean master of the text and make the other formats from it.

Making a good one

• Two lines at most per entry, with a comfortable line length, so the viewer reads without chasing the screen.
• Break lines at a natural pause, not in the middle of a phrase.
• Leave each entry on screen long enough to read, and never let two overlap.
• Re-time the whole file if the edit changes: a few frames removed early on shift every later entry.

If the video will go out in several languages, each language is its own SRT, with its own timings, because the translated sentence is rarely the same length as the original.