ffmpeg command to add .srt based subtitles to an .mkv file

mkv embed soft subtitles

ffmpeg -i in.mkv -f srt -i in.srt -map 0:0 -map 0:1 -map 1:0 -c:v copy -c:a copy -c:s srt out.mkv

To just add subtitles to file without removing any subtitles it is very easy:

ffmpeg -i input.mkv -i input.srt -map 0 -map 1 -c copy output.mkv

-map x selects all streams from a file so all streams from both files get into the output file.

See the very conscious and simple documentation https://trac.ffmpeg.org/wiki/Map

P.S. Thanks @eladkarako for the metadata usage

I've tried all the above options without success... the only thing that happens is that there is a closed caption option listed yet no text is displayed and the file size of the video file was increased.

I'm using both mediainfo and vlc to look at the file info.

I'm running this thru a ubuntu server 22.04.1 LTS

is this supposed to add the CEA-708 metadata for Closed Captioning or is this a different type of embedded text?

I've tried all the above options without success..

This code I use both on my PC and my server, works perfectly, the sub file should be .ass format (use aegisub or even ffmpeg to convert your sub to it)

ffmpeg -loglevel 16 -i input.mp4 -f ass -i sub.ass -brand isom -tag:v avc1 -map 0:0 -map 0:1 -map 1:0 -c:v copy -c:a copy -c:s ass -disposition:s:0 default Fname.mkv

ffmpeg -i $1 -f ass -i $2 -map 0:0 -map 0:1 -map 1:0 -c:v copy -c:a copy -c:s ass $RANDOM.mkv

I confirm this code is fine.

Thanks.