[mythtv] Discussion: make playback available in all UI screens

[Joseph A. Caputo]

I thought I'd start a thread to discuss ways in which the following 
might be implemented: when any media playback is initiated (using a 
Myth internally-supported playback mechanism; i.e., not mplayer), the 
playback process will be a daemon, and the output should be available 
no matter where in the UI you are.

Now, before everybody jumps on me, I do know about the new mfd stuff 
Thor's been working on, and that's a step in the right direction.  
However, I'm thinking more along the lines of LiveTV or 
WatchingRecording... what if the video playback in Myth was also part 
of mfd (or some other daemon process)?  Then the playback could 
continue even if you switch to a different menu.  Kind of like the EPG 
is now in LiveTV.  Any theme that wanted to could contain a "black 
hole" UI element that would contain any currently-playing video.  If 
there was no video currently playing, then the "black hole" would not 
be displayed.  A jump point or global keybinding could take us back to 
full-screen mode.  For any screen that did not have a black hole, the 
playback would continue, but the video would be redirected to a null 
device, or behind the window, or whatever.  You'd still get audio.

Basically, the idea is that once a media playback event is initiated in 
Myth, it should only be stopped by:

- user explicit action to stop it
- reached end of playback
- Myth requires the resource (i.e., LiveTV & Myth needs tuner for 
scheduled recording)

This seems relatively easy for audio media w/ the new mfd client module; 
it can obviously keep the audio output device open regardless of what 
you're doing in the UI; it's just the video/black hole stuff that 
requires thought.

So, anybody else have thoughts on this?

-JAC