[mythtv] Closed captions after libmythui-osd merge

[Jim Stichnoth]

I have analog closed captions enabled by default (DefaultCCMode=1 and
PreferCC708=0).  After updating trunk and getting the libmythui-osd
branch merge, there's something broken about the captions.  When
playback starts, captions are not displayed.  But if I bring up the
OSD menu for "Select VBI CC", the cc track is highlighted, indicating
that at some level the system thinks captions are enabled.
Re-selecting captions brings them back, de-selecting makes them go
away; in short, everything works fine except for the initial startup
of playback.

I tried looking at this in the debugger.  It seems that
NVP::EnableCaptions() is actually being called twice when playback
starts.  The first time it is for CC708 captions.  The second time is
for CC608 captions -- it looks like the first CC608 packet has been
found and so it switches from CC708.  While stepping through the
debugger, I think the second call started before the first call
finished, so there may be a race condition.  The function has a
comment "caller has decoder_changed_lock" but that doesn't appear to
be accurate.  Interestingly, when I resumed in the debugger, captions
started appearing normally.  (This could be a timing issue, or it
could have to do with exactly where the bookmark is when I start
playing; I didn't do a whole lot of testing.)

On a slightly related note, my caption font has unexpectedly changed
since the upgrade.  OSDCCFont is still set to FreeMono.ttf but I'm now
getting a proportional font instead of monospaced.  Log messages like
this:
  2010-06-09 06:16:03.411 Subtitles: Loaded main subtitle font
suggest that the right font is being loaded, but it doesn't seem to be
actually used.

Jim