Old, old hand at computers, here (yes, I once had a state-of-the-art 300 baud modem) -- but very, very new to streaming. I recently (two days ago) connected a Roku 3 to my TV. I have many of my DVDs saved in VIDEO_TS-VOB/IFO/BUP directory/file format on a USB drive plugged into the back of a WD My Cloud (single 4TB drive). I soon discovered that I could not play my movies via the existing Twonky server on the WD NAS and Roku Media Player.

After much searching online, I found what looked like the simplest way to play those files in Mezzmo. The installation of the server on my Windows 10 PC was painless, if lengthy. (I'm guessing because of default settings causing some kind of transcoding to be done to nearly 300 movies?) The installation of the Mezzmo player on the Roku was even simpler. I was very pleased to find the accurate list of movies, for starters. (I had tried Plex beforehand, only to have it present me with hundreds of Vobblanker backup directories as "movies." Plex has been uninstalled.) Also nice were the poster art and metadata on the display. (Offhand, I noticed at least one wrong graphic (for Cary Grant's "Harvey," but I haven't really checked these for accuracy, yet.) All in all, very nicely presented!

The surprise I wasn't crazy about was the subtitles that were burned into the video by default. It took a lot of research to figure out how to stop it and get rid of the files already written. (I came into this streaming experience knowing nothing about how subtitles are stored and handled. I still know only that there are such things as embedded and external subtitles; I haven't much of a clue as to how they are handled, when they are handled the way they are (VOB vs. MP4 vs. MKV vs. MOV vs.... let alone hardware/firmware considerations). So, I am left wondering one or two things:

1) Is it possible to set up Mezzmo in such a way that my Roku 3 will recognize the subtitle data in DVD files (vobs?) and allow me to turn it on and off dynamically, via the remote control? (Currently, Roku keeps telling me there are "No captions or audio selection available.") I have tried various setting combinations under Mezzmo menus Tools->Options->Subtitles and MediaServer->MediaDevices->RokuStreamingPlayer->Edit->[Subtitles/Transcoding], without success. (Admittedly, I might have missed a combination or two.)
2) If it IS possible, what specific settings should I use?

I've figured out how to burn the subtitles in or turn it off, but I'd really like to be able to turn the subtitles on or off, "on the fly." I prefer to watch a movie uncluttered by subtitles, but there are times when the dialog is hard to make out and the subtitles come in very handy. Thanks, in advance, for any advice.