So what I was saying was to take the textbased sub, use the graphics-based tool you've been trying ( 3D Subtitler), output it to Vobsub and then re-convert it back to SRT (using whatever tool works best for this).ฤก.
If you can do this automatically in batch-mode with Text-based subs, great, but I don't think there are ANY auto/batch tools or methods that would work with that (at least yet). And this must be one with an horizontal offset such that the resulting playback puts the subs' dimensional plane IN FRONT of the depths of all the background video (otherwise, you get a very disconcerting disconnect in your perceptions). So, IF this is the requirement, then you have to modify an SRT such that upon playback it acts as if it had been prepared the same way a graphic would have been prepared: where you combine L+R views and anamorphically squeeze in half one dimension to get the overall dimension back to standard 2D. If your player ONLY supports SRT subs (which are text-based), as opposed to PGS or anything else graphics-based, WHILE PLAYING MKVs, then you have to put your subs into SRT format (either externally as file in tandem with MKV using same filename, or internally muxed into the MKV). I'm guessing that's what you meant when referring to SRT (at least in 2D mode). The PGS would have to be exported/converted to a format that, when played ALONG WITH the MKV, will still be supported, right? If your player supports BD subs (PGS), but only when playing BD or AVCHD material, then that is of no use to you if you are trying to play MKV material. I think we all need to be clear (I'm not yet) about WHICH kinds of subs your player+TV combination can use, and under what circumstances.