srt (“SubRip”)

doc

https://ffmpeg.org/ffmpeg-filters.html#subtitles-1, https://en.wikipedia.org/wiki/SubRip

Watch on youtube.com

Texts embeded in this video was made by using with “SubRip” like this:

desc.srt

1
00:00:00,000 --> 00:00:05,500
Unofficially the format has very basic text formatting,

2
00:00:05,500 --> 00:00:10,500
which can be either interpreted or passed through for rendering
depending on the processing application.

3
00:00:10,500 --> 00:00:30,000
Formatting is derived from HTML tags for <b>bold</b>, <i>italic</i>, <u>underline</u> and <font color="red">color</font>.

[me@host: ~]$ ffmpeg -y -i input.mp4 -vf "subtitles=desc.srt" -c:a copy output.mp4