What does SRT stand for? On a computer, it almost always means SubRip Subtitle, a simple text file that holds the captions for a video. If you have downloaded a file named something like lecture.srt, it contains the words people say on screen, each line tied to the moment it should appear.
The name comes from SubRip, an old program that pulled subtitles off DVDs and saved them in this format. The format outlived the program because it is easy to read and nearly every video player supports it. A few other fields use SRT too, from cars to live streaming.
Quick facts
Stands for
SubRip Subtitle, also called SubRip TextType
Initialism and file extension (.srt)How to say it
S R TWhat is inside
Numbered captions with start and end timesOpens with
Any text editor, most video players and editorsOther meanings
Street and Racing Technology, Secure Reliable TransportRelated terms
Captions, subtitles, VTT
What does SRT stand for in video files?
The letters come from SubRip and Text or subtitle, and the extension .srt marks the file. It is not a video and holds no pictures or sound. It is a list of short text blocks, each with a number and a time range, so a player knows which words to show and when to hide them.
Because it is plain text, you can open an SRT file in any basic text editor, fix a typo, and save it again. That ease is the main reason the format is so common for online courses, home videos, uploaded clips and foreign language films.
What an SRT file looks like inside
Each caption block has four parts: a number, a timing line, one or two lines of text, and a blank line.
Two captions from a cooking video:
1
00:00:02,500 --> 00:00:05,000
Start by melting the butter.
2
00:00:05,400 --> 00:00:08,100
Keep the heat low so it does not burn.
The timing line reads hours, minutes, seconds and milliseconds. Note the comma before the milliseconds, a small detail that sets SRT apart from some similar formats. The arrow between the two times means "from this moment to that moment."
How SRT files are used
- Uploading captions to a video site or a school learning platform, so viewers can turn them on.
- Translating a video by swapping the text while keeping the timing.
- Accessibility, giving deaf and hard of hearing viewers a way to follow along.
- Editing, where video software imports the file and places captions on the timeline.
- Watching at home, by placing the .srt file in the same folder as the video with the same base name.
Captions and subtitles are related ideas. Captions usually include sound cues such as [door slams] for viewers who cannot hear, while subtitles often just translate speech. An SRT file can hold either. Turning them on is usually the CC button.
SRT vs VTT and other caption formats
| Format | Extension | Key difference |
|---|---|---|
| SubRip Subtitle | .srt | Simplest layout, comma before milliseconds, little styling |
| Web Video Text Tracks | .vtt | Starts with a WEBVTT header, uses a period before milliseconds, allows positioning and styling |
| Plain transcript | .txt | Words only, no timing, so a player cannot sync it |
Many tools convert between SRT and VTT in seconds, since the content is almost identical. If a site rejects one, try the other.
Other things SRT can stand for
- Street and Racing Technology: a performance badge used by an American automaker group on high powered cars and trucks. On a car, SRT signals a faster, sport tuned model, not a subtitle.
- Secure Reliable Transport: an open source protocol for sending live video over the internet with low delay, used by broadcasters and streamers.
- Speech recognition threshold: in hearing tests, the softest level at which a person can repeat simple words correctly about half the time.
Look at the setting. A file name or video menu points to subtitles, a parking lot points to the car badge, and a streaming setup screen points to the protocol.
Tips for working with SRT files
- Save the file with UTF-8 encoding so accented letters display correctly.
- Keep each caption short, about two lines at most.
- Match the file name to the video name for automatic loading.
- Check the timing by playing the video, not just by reading the numbers.
Explore more file and web terms like HTML and GIF across our tech acronyms hub.
Questions people ask
What is an SRT file?
It is a plain text subtitle file. It lists numbered captions with start and end times so a video player can display the right words at the right moment.
How do I open an SRT file?
Any text editor will open it for reading or editing. To watch it with a video, load it in a media player or put it in the same folder as the video with a matching name.
Is SRT the same as closed captions?
An SRT file can carry closed captions, subtitles or both. The format is just the container for the timed text.
What does SRT mean on a car?
On certain American performance cars and trucks, SRT stands for Street and Racing Technology. It marks a high performance version of a model.
What does SRT stand for in streaming?
In live video, SRT stands for Secure Reliable Transport, a protocol that helps send video over the internet smoothly and with low delay.