[mythtv-users] Preview Errors caused by superfluous LiveTV zero length files?

[Tom Dexter]

I frequently get these preview errors in my mythbackend.log.

2008-04-13 12:29:01.342 Preview Error: Previewer file
'/video/recordings/1051_20080413122857.mpg' is not valid.
2008-04-13 12:29:01.343 Preview Error: Run() file not local:
'/video/recordings/1051_20080413122857.mpg'
2008-04-13 12:29:01.349 Preview Error: Preview process not ok.

fileinfo(/video/recordings/1051_20080413122857.mpg.png) exists: 0
readable: 0 size: 0

I've been able to determine that they're occurring because, every time
I enter LiveTV or change channels in LiveTV, a zero length mpg file
gets created in addition to the valid file that gets streamed to the
frontend.  It gets auto expired and disappears shortly after.  I had
this issue in 0.20.2.  It's never caused any problems, but I thought
for sure this would be fixed in 0.21.  In 0.21 I've also been
occasionally getting these in the mythbackend.log:

2008-04-13 13:00:30.833 Preview Error: Encountered problems running
'/usr/bin/mythbackend --generate-preview 0x0 --chanid 1071 --starttime
20080413124200 '

I'm not sure what's trying to do that, but the '0x0' part certainly
looks suspect...maybe those are related to the bogus zero length
LiveTV files as well.

Is anyone else seeing any of the above?  Like I said...the extra zero
length LiveTV mpg files have been occurring ever since I first built
the system and they happen every time I enter LiveTV or change
channels without fail.  For example, I just went into LiveTV and
surfed though a few channels and get this:

/video/recordings $ find . -size 0
./nfslockfile.lock
./1021_20080415145909.mpg
./1041_20080415145916.mpg
./1051_20080415145926.mpg

...and here are some of the zero length files along with the valid
ones that get streamed to the frontend:

/video/recordings $ ls -alt *.mpg
-rw-r--r--     1 mythtv video    12806560 Apr 15 14:59 1051_20080415145928.mpg
-rw-r--r--     1 mythtv video    12549188 Apr 15 14:59 1041_20080415145918.mpg
-rw-r--r--     1 mythtv video                  0 Apr 15 14:59
1051_20080415145926.mpg
-rw-r--r--     1 mythtv video      8618484 Apr 15 14:59 1021_20080415145910.mpg
-rw-r--r--     1 mythtv video                  0 Apr 15 14:59
1041_20080415145916.mpg
-rw-r--r--     1 mythtv video                  0 Apr 15 14:59
1021_20080415145909.mpg

Also, I have "Display thumbnail preview images of recordings" turned
off for my frontend.  Does the backend try to generate them for all
recordings anyway?  I suppose in any case they'd be needed for mythweb
even if no frontends used them.

I use the "Display live preview of recordings option"...speaking of
which (getting a little OT here)...where did the low cpu option for
the live preview go in the setup menus?  I still have it set in the
settings table (PlaybackPreviewLowCPU), but I don't see it anywhere in
the menus...it's definitely not on the same screen with the "Display
live preview" option.

Thanks
Tom