Interesting you mention VOD, all of my VOD has subtitles, well over a thousand movies currently available and all with subttiles, I can put you in touch with my supplier if you like who offers a trial so you can see for yourself?
I've exploored this in detail although have come to the conclusion it's not possible. Subtitles are available when the stream has subtitles encoded into it, when this happens, the player can decode and display them just fine. I've found that BBC, ITV and channel 5 are the only providers which...