TvService crash on channel change
#1
Hello there,

I've installed the Frodo RC together with the MediaPortal service and the TvServiceXBMC plugin. From time to time, when I change channels, the service crashes before completing the operation. I then used WinDbg to see where the failure occurs. It turned out that VBICodec.ax causes a segfault. Further tracing in the TvService source revealed that his seems to happen in a call to IMediaControl::Stop() when the TV filter graph is stopped. My workaround is to disable the instantiation of the VBI filter which works for me now.

While this may seem to be a bug in the MediaPortal service or VBICodec itself, I'm posting this here since this only occurs in XBMC. If I use MediaPortal as the front end, TV works without any crashes. This may hint towards the TvServiceXBMC plugin whic may use the TVController in a way it doesn't expect to be used (maybe a rare race condition?). Any hints on how to debug this further?

Here are some specs that may be interesting:
Win7 32bit
TV Card: ASUS MyCinema PE-6200 (analog card w/ hw MPEG2 encoder)
MediaPortal 1.2.3
XBMC Frodo RC
Nvidia ION
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#2
Never heard of this problem before. Maybe it is related to analog tv. I'm only testing with DVB-T/C. I will see if I can reproduce it when using the analog tuner of my hybrid card.

Difference between the MediaPortal client and the XBMC client is currently that I'm calling a stop timeshift followed by a start timeshift on a channel switch instead of only a retune (without stopping the timeshift).
To get the same behavior as a MediaPortal client, you could enable the "Fast channel switching (don't stop timeshift)" option to see if this makes a difference.

Another option would be to run the TVServerXBMC plugin in standalone mode: disable the plugin and run the TVServerXBMC.exe version instead to see if it makes a difference.

Only further hint for debugging is the programmers hint to download the C# TVServerXBMC sources from my github account and use MS VC# express 2008/2010 to debug the extension.
Developer of the MediaPortal PVR addon and retired developer of the Argus-TV PVR-addon.
http://www.scintilla.utwente.nl/~marcelg/xbmc
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#3
Thanks for the reply! I forgot to mention that I already used the .exe version of the XBMC bridge but the behavior is the exact same. The "TimeshiftChannel" command fails with a socket write error which is caused by the TvService crash, so the StopTimeshift is the cause. Enabling the fast channel switch option indeed solved the problem for me.

Imho a stop-then-start shouldn't be a problem for the TvService so I should probably cross post this to the MediaPortal forum so that they can halp me find the race (or whatever bug this is) in TvService.
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