MythTV not displaying captions
 

For some reason, when I turn on captions in either a recording or live tv, nothing happens. I don't see any text displayed at the bottom of the screen. I am using a hauppage hvr-850 on local over the air atsc channels in houston, tx. in mythtv-setup the vbi is set to ntsc. when i hit "t", nothing happens. when i hit "m" and scroll down to see select atsc cc, and i pick english, still nothing. what am i doing wrong?

fixed it accidentally. i switch the deinterlacer from linear to none and then to bob2x and it showed up again. why, i don't know.