[mythtv] Massive file size when recording and watching simultaneously

[Mark Covington]

I'm finding that when the backend records a program using default RTJPEG 
settings (quality 170) and it takes about 1.5GB to record a 30min show 
which is normal.  However, if I'm using the frontend at the same time to 
watch another recording the file size will balloon to several times 
normal.  I had one 30 min show take up 12GB when it was done.  It seems 
proportional so that if I record and watch another program while there's 
only 5 min left in the recording it will only increase the size to ~4GB. 
I used nuvinfo to compare a normal recorded file and a file that 
ballooned up size and they only differed in
keyframeadjust_offset:  0 vs 2
and seektable_offset:  1367364839 vs. 1490857276

Frontend and backend are on the same machine, never had any problems 
until about a month ago.
So obviously something extra is getting added to the file, but I can't 
find anything obvious.  Running recent CVS (11APR), but haven't seen any 
commits since then that would fix this.

Mark