After more testing, I've discovered something that may work.
- Make a copy of the original video file (a .M4V file that has a Subtitle Track)
- Open the .M4V file in QuickTime Player (version 10.3 - don't try using QuickTime Player 7)
- In QuickTime Player, from the View menu, choose "Subtitles: English" (or whatever language you have)
- Play the movie, verify that the subtitles are visible
- Save the movie file.
- Go back to Keynote, and select your original video file, click the Format/Movie inspector and choose "Replace" - then select the new filename.
After doing these steps, I am seeing the Subtitles show up when played through Keynote 6.2.
It seems that Keynote 6 will only play subtitles in M4V files.
If you have a MOV file with a Text track, then it won't work. There is a workaround, if you have access to the original captioning files and can re-export as an SRT track:
- Get the app Subler from http://code.google.com/p/subler/
- Open your MOV file in Subler and select the default Audio and Video tracks.
- Click the + button in Subler, and add your .SRT captioning track.
- Save the file as Vidoe-MPEG4 format (which is .m4v )
- Open your new m4v file in QuickTime Player X
- Enable Subtitles from the View/Subtitles menu
- Save the M4V file
- Use this new m4v file in Keynote 6, and now you should have high quality subtitles.
And, for the record, I'm sure nobody cares, but updating my Keynote 5 presentations for Keynote 6 took me about 17 hours, for a single presentation that I use for a class I'm teaching, in which I often have hearing-imparied students, so closed-captioning is critical.
17 hours includes the time to fix all the Closed-Captioned media the Keynote 6 no longer supports, as well as ditching the obsolete QuickTime "MOV" format (what idiot company invented that ***** anyway???) and updating to M4V.
When I'm all done, the 5.2GB presentation drops back to 60MB (with all videos properly externally stored, just like I had it in Keynote 5).