[mythtv] Shm detection + frame decimation environment variable

[Chris Palmer]

Chris Pinkham wrote
> I also added in a little bit of code to the Show() function to calculate
> how many frames are processed in the first 4 seconds.  If it determines the
> fps is too slow, it will print out a message and will skip frames similar
> to your mod in order to keep the audio and video in sync.  

Is this taking the first 4 seconds as a benchmark for how much
frame skipping to do in general, or is this only under special
cases?  I'm expressing concern because every time I play a show
on my remote frontend, the first couple seconds (only) are
choppy and I wouldn't want the whole show to be skipping frame
just because I missed a few at the start.

Or does this stuff only apply to remote-X playback?  :)

-Chris