[mythtv-theming] template tag syntax

[Joey Morris]

In video-ui.xml, I'd like to display the title and subtitle in the
same field, separated by a colon. If there is no subtitle, I don't
want to the colon to appear. (Unfortunately it doesn't appear that
video-ui.xml supports the titlesubtitle element like recordings-ui.xml
does. If that were available, I think it would work for me.)

I started off with a simple:

  <template>%TITLE%: %SUBTITLE%</template>

That of course always displays the colon whether there is a subtitle
or not. The wiki doesn't describe any more advanced syntax, so I
thought I wouldn't be able to do what I wanted until I found these
threads that discuss the vertical bar syntax:

  http://www.gossamer-threads.com/lists/mythtv/theming/453231
  http://www.gossamer-threads.com/lists/mythtv/theming/453448

That looked promising. Even though I'm not entirely sure I understand
how it's supposed to work, based on the examples in those threads and
in other themes, it seems like this should work for me:

  <template>%TITLE%%: |SUBTITLE|%</template>
  
However, what I get is something like this:

  My Video Title%: |SUBTITLE|%

whether the video has a subtitle or not. What am I doing wrong?

Output of mythfrontend --version:

MythTV Version   : v0.24-249-g4fe108c
MythTV Branch    : fixes/0.24
Network Protocol : 63
Library API      : 0.24.20101129-1
QT Version       : 4.7.0
Options compiled in:
 linux debug using_alsa using_oss using_pulse using_pulseoutput using_backend u\
 sing_bindings_perl using_bindings_python using_dvb using_firewire using_fronten\
 d using_hdhomerun using_hdpvr using_iptv using_ivtv using_joystick_menu using_l\
 irc using_mheg using_opengl_video using_opengl_vsync using_qtdbus using_qtwebki\
 t using_v4l using_v4l2 using_x11 using_xrandr using_xv using_bindings_perl usin\
 g_bindings_python using_mythtranscode using_opengl using_vdpau using_ffmpeg_thr\
 eads using_live using_mheg