If yes, maybe you can refer to my solution below.
Many of the blu-ray player has USB features which supports MKV, AVI, TS playback file format.
Especially MKV movie format that supports on DTS and AC3 that has 5.1 channel surround mode.
But many of the MKV movie do not has subtitles along together.
Now you can use "mkvmerge GUI" to combine language subtitle ".srt" into the MKV file.
Maybe you will think of "will it takes long time" to process the merger?
The answer would be merger of subtitles into mkv won't takes long time. Normally i spent around 4~5min to merge the subtitle into movie file.
You will need the software of mkvtoolnix application as below,
official web: http://www.bunkus.org/videotools/mkvtoolnix/downloads.html#windows
3. Click "add" for searching the MKV file that you wish to merge the subsititle.
4. After you add-in the MKV movie clip from directory that you've choosen, it will display as above picture.