SSRT

SSRT is short for Simple Subtitle Resource Tracks, or Simple SRT. SRT is a file format to create video captions. SRT format is repetitive because it requires an index and a start and end time for each subtitle. Simple SRT is more user-friendly. Write your subtitles in SSRT format and use ssrt2srt to get equivalent SRT file.

For example, create a file test.ssrt with:

00:00:2000 first line
00:00:4000 second line

Transform it to SRT:

$ ssrt2srt test.ssrt > test.srt
$ cat test.srt
1
00:00:0000 --> 00:00:2000
first line

2
00:00:2000 --> 00:00:4000
second line