How to soft code an MKV with subtitles?
Solution 1:
Use MKVMergeGUI.
mkvmerge and mkvmerge GUI (or just mmg) are two programs created by Moritz Bunkus. They're part of the mkvtoolnix package. mkvmerge can read a lot of different multimedia files and put their contents into Matroska files. Unfortunately this is a command line program, and not everyone is comfortable working on the command line. This is where mkvmerge GUI comes into play. It is a GUI that provides the user with an intuitive but powerful interface to mkvmerge.
Try this example (source):
mkvmerge -o out.mkv input.avi input.srt