[mythtv] commflag debugging

Jim Westfall jwestfall at surrealistic.net
Mon Jan 2 01:01:20 EST 2006

Chris Pinkham <cpinkham at bc2va.org> wrote [01.01.06]:
> > I would like to look into some commflag debugging.  I see there are 
> > already bits in place to display/dump frames, but the support functions 
> > for them dont resolve.  I suspect they are defined in commercial_debug.h, 
> > which is commented out in ClassicCommDetector.cpp but doesnt exist within 
> > svn.  Curious if anyone knows where I might find it.
> commercial_debug.h is something I use locally but never committed to
> cvs or svn.  Attached is a copy.
> It's a quick hack, but accomplished what I wanted when I threw it
> together a few years ago. :)
> To use, just uncomment the #include line and recompile.  Also, for some
> more verbose debugging than the normal "-v commflag", you can define an
> environment variable called DEBUGCOMMFLAG and that will cause a lot more
> verbose debugging information to be displayed.

Thanks that helped alot.  So debugging stuff commflag is correctly finding 
the commercials, but something weird is going on during playback.  The 
actual video frames and frame numbers are not matching up between 
mythcommflag and mythfrontend.  

In the main recording I have been looking at commflag finds the first 
break as frame 40130 (verified with your debugging code).  When this video 
frame (not number) shows up in mythfrontend its frame number 37319.  This 
of course screws up commbreak skips, when mythfrontend get to what it 
calls frame #40130 ist no where near the commercial.

One thing I have noticed is the positionMap on this recording is short.  
The last entry is for frame 200255, but there are actually 215594 in the 
recording.  When playing the recording to the end it shows its only played 
200255 frames, but it does show the entire program.  

So I am wonder if there is some frame drop mechanism that is dropping 
the 15k frames uniformly over the course of playing the recording and it 
isnt increasing framesPlayed when it does.  Then framesPlayed is getting 
out of sync with the actual frame number, which the commbreaks are based 


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