[mythtv] Video Output patch (incl. Windows & OSX) v11

[Daniel Kristjansson]

This is an update on the Xv/XvMC patch.
The patch is here:
   http://www.mrl.nyu.edu/~danielk/mythtv/xv-xvmc-merge-v12.patch.bz2

>From the known problems in the last patch:
> >  3/ There is an OSD or pause issue which can cause hard lockups on
> >     some systems with a GeForce4 MX GPU.

The problem was mostly that available_wait.wakeAll() was sometimes
being called when only one frame was available instead of only when
EnoughFreeFrames(void) was true. Fixing that fixes the problem with
Lo-Def TV, and with OSD in HDTV. However, there is still a problem
with Jumping backward and forward in HDTV. My guess is that
DiscardFrames() may need to be more aggressive, i.e. hide visible
XvMC surfaces so that more frames can be freed, or discard old pause
frames more quickly. But I need to do some more debugging. This is
not causing a playback lockup, but only because I'm resetting
videoout in NVP after 10 prebuffering waits.

I've seen some "Xlib: async reply..." messages on HDTV playback
lately so I've added a lock around XvMCRenderSurface() and
XvMCPutSurface(), this seems to have cured it. But these
messages weren't very frequent so I'm not sure yet.

-- Daniel