mythbackend constantly crashing (SVN trunk)

[anonymous]

I'm running the latest mythtv from SVN on my Ubuntu 7.04 (Feisty) x86_64 box. And lately (sometime in the past few weeks) I haven't been able to get mythbackend to run consistently. I can crash it simply by choosing to Watch TV for a few minutes, going back to the main menu, and then when I select Watch TV again, mythbackend crashes. I'm attaching myth.log and also the gdb output I generated by following the procedure written about here: http://www.mythtv.org/docs/mythtv-HOWTO-22.html#ss22.2

[johnfivealive@…]

GDB Debug Log

[johnfivealive@…]

Log of Crashed mythbackend Debug Run

[anonymous]

I am also having this problem running latest SVN on gentoo stable.

[xris]

crash from revision 14542. Seemed to crash during a recording (firewire, came out to zero bytes).

[anonymous]

I originally reported this bug and I'd like to report that as of compiling and installing MythTV from SVN revision 14648, mythbackend is no longer crashing. Was this bug deliberately fixed? If so, I'm curious to know what the solution was. If it starts crashing again over the next few days (or in newer SVN revs.), I'll report back here.

[anonymous]

Me again, I think I spoke too soon, the crashing has come back, though it seems less frequent now.

[johnfivealive@…]

The backend crash is still happening periodically, here's the message that appears in the syslog when it crashes:

mythbackend[12166] general protection rip:2b454a7cf584 rsp:4a016b88 error:0

[illesNOSPAMatG__MAIL.cOM]

I've experienced this same phenomenon on my ubuntu gutsy with mythbuntu + mythtv 0.20.2. I managed to locate the cause of it!

It seems that when I use RTJpeg for the TV record and set it to a quality higher than around 210-220+ it begins to crash when recording is starting with general protection message (kernel 64 bit catches the mythtv segfault). So if I set quality of RTJpeg around 170 I do not experience the problem.

System: AMD 64 x2, Gutsy AMD64bit, kernel 2.6.23.8 custom and with original gutsy kernel too.

[johnfivealive@…]

As the above commenter suggests, the problem is possibly with the rtjpeg/mpeg2 codec (ffmpeg?). I switched my Default and Live TV encoders to MPEG4 and the backend has been stable ever since (hasn't crashed once), though I saw the frontend crash a couple times now for reasons which I can't explain.

So, I guess there must be some bug in ffmpeg that only gets triggered on systems running an 64-bit OS. Or it could be something else, but the problem most likely stems from some bug with mpeg2 processing on AMD 64 Linux.

I should mention that I reverted back to the latest version of MythTV as packaged by Ubuntu Gutsy, but I was experiencing this same bug with this older version. I'm assuming the bug still exists in SVN trunk, though I have yet to verify this.

[danielk]

This was fixed a couple weeks ago in [15470].

[illespal]

Hope it's so although I cannot really see the relation yet between these too things if it isn't a thing about it's trying to initialize recording twice because of problems with the codec, I will test it if the new package comes out.