[ATrpms-users] MythTV Hang - Stream that causes mythbackend and mythcommflag busy-spin

[ejgraves@excite.com]

Hi,



Thanks to Axel and all who work on atrpms (especially the mythtv-related packages). I'm running ATRPM's built mythtv on Fedora Core 4, and overall the packages have been working out well for me. I have however run into a minor problem (which may well exist in any .18 build of myth?).



I just encountered an ATSC stream (captured via HD3000 card) that causes mythbackend to busy-spin (taking 99% CPU) when it attempts to make a thumbnail. The same stream causes the same thing to happen to mythcommflag. (It seems like it may be a corrupt, or at least "unexpected by the decoder" stream.) 



Being relatively new to myth (and not yet building it myself), is it "interesting" to anybody to see the stream (or at least the first "n" bytes of it) that causes the hang? Since it's an ATSC stream, it's quite large, and my connection isn't very good for posting multi-gigabyte files (if the first few hundred MB would suffice, no problem).



ls -al 1017_20051231163000_20051231173000.nuv

-rw-r--r--  2 mythtv mythtv 6585836579 Dec 31 17:30 1017_20051231163000_20051231173000.nuv



I'd also be happy to collect backtraces with gdb while it's in the "busy-spin" state, but the ATRPMS installed binaries are stripped, so the results aren't very useful:

% file `which mythbackend`

/usr/bin/mythbackend: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.5, dynamically linked (uses shared libs), for GNU/Linux 2.2.5, stripped





When played with mplayer, mplayer gives a whole bunch of "a52: CRC check failed" and "a52: error at resampling" messages--but mplayer doesn't hang/busy-spin.



In the meantime, I've found (a few) workarounds that at least prevent the busy-spin (in case my workarounds are useful to anyone else).



Workarounds:



As a short-term hack workaround, I hardlinked a dummy.png thumbnail file to 1017_20051231163000_20051231173000.nuv.png. This way, myth (in particular, mythweb which is what I tend to use most) doesn't try to create the thumbnail.



For mythcommflag, I simply disabled commercial flagging for the time being. 



For mythweb thumbnail generation, is there a way to disable thumbnails in mythweb when installed from the built images? I looked, but could not find documentation for mythweb that covered how to disable thumbnails.



The versions I have are as follows (yum list installed):

mythtv-backend.i386                      0.18.1-116.rhfc4.at    installed       

mythtv-frontend.i386                     0.18.1-116.rhfc4.at    installed       

mythweb.noarch                           0.18-68.at             installed       





Thanks,



-eric

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