[mythtv-users] Patch available for mythfrontend freeze

faginbagin mythtv at hbuus.com
Wed Jan 16 03:06:41 UTC 2008

I was having frequent problems with mythfrontend/mythvideo freezing up 
when I was watching recordings made on a DVD recorder and imported into 
mythvideo. When I would fast forward past a commercial, rewind when I 
went too far, and then resume play, I never knew if I'd be stuck. 
Mythfrontend would not respond to the remote or the keyboard. The only 
work around was to kill the process and restart it. And then chances 
were good I'd hit the same problem, just trying to get to where I'd left 
off viewing.

I found the freeze was due to a deadlock between two threads, each 
wanting the lock (mutex) that the other had and I think I've fixed it. 
At least, I can't reproduce it, after trying and trying. So I'm happy 
and want to share with the mythtv community.

But there's a hitch. I'm using version 0.20.2 
(mythtv_0.20.2-0ubuntu10.1, to be specific), and mythtv developers are 
really only interested in fixing bugs known to exist in the latest trunk 
version. As a developer myself, I understand that position. But I don't 
have a second machine, I've become dependent on mythtv and I don't want 
to risk what is now a stable environment by switching to trunk. I do 
know that the code I changed is the same between 0.20.2 and trunk, so 
it's possible the problem does exist in trunk.

So, I'm wondering if there's anyone else who is having this problem and 
finds it annoying enough to be willing to compile mythtv to fix it.

The fix only works if you've configured mythfrontend to use XvMC. In my 
case, I have an nVidia 7300 LE GPU and have set "Preferred MPEG2 
Decoder" to "Standard XvMC" in mythfrontend's TV Settings -> Playback. I 
suspect there's also a connection to the display of NTSC closed captions 
or PAL teletext, but I'm not totally sure. In my case, the recordings 
are NTSC and CC display was on.

Here are more details on my mythtv setup:
ECS RS482-M754 motherboard
AMD Sempron 3100+ 32 bit CPU
Hauppauge WinTV-PVR-150 model 1045 with IR blaster & receiver
Biostar graphics card with an nVidia Geforce 7300 LE GPU
Two HDDs, 80GB (the O/S) & 500GB (dedicated to videos)
500W PSU
IDE CD burner
Ubuntu gutsy 7.10
mythbuntu control centre 0.10-0ubuntu1.1

I have posted a patch to the source code in two locations:

I hope it helps someone besides me. If it does, please let me know. If 
you think it might help, but aren't sure, let me know. I'd be happy to 
answer your questions.

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