MKVMerge and vobsub

[Asterra]

So I realized the other day that I could probably convert all my ripped (to MPG) DVDs to MKV and save a bit of space. First one I tried had some subtitles. I couldn't help but notice that MMG made no note of a subtitle track when I added the MPG as a source. And the MKV it spat out... indeed lacked any subtitles at all. They just vanished.

Eventually I'm going to hit a movie where I'd really rather not lose the subs. Is there something I can tweak that will make MMG aware of the subtitle tracks in files where it evidently shows no such awareness by default?

[hello_hello]

I can't imagine there'd be much space saved when only changing containers, unless you're removing unwanted audio or something, which you could do while keeping the DVD format, but anyway... I suspect that's a job for MakeMKV.