.SRT is a plain text file used for recording movie subtitle information. Each entry in the .SRT file contains the start time and end time during which the subtitle is to be displayed. Using .SRT file, it is possible to display subtitles without actually encoding the text inside the movie. Since the only data required is the play time, this file format is compatible with Divx and other movie formats.
.SRT files are very popular among online movie pirates and are usually released along with the movie torrents. There are a lot Web sites which exclusively host .SRT files (for example opensubtitles.org).
The following shows a sample entry of an SRT file:
00:03:24,350 –> 00:03:28,800
She had good looks and coal black hair
The above is the sixth subtitle in the movie and will be displayed between 3 minutes 24 seconds and 3 minutes 28 seconds (note the precision up to millisecs!). The actual subtitle displayed is "She had good looks and coal black hair."
A wide range of video playback software supports .SRT subtitle files. Some of them are - VLC media player, CyberLink PowerDirector, and Windows Media Player (with VobSub plugin). Typically .SRT files are configured in the media player before playing the corresponding movie.