[mythtv-users] Mythfrontend crashing - libavcodec miscompiled diagnostic

[Paul Harrison]

JCA wrote:
>   I recently upgraded my Slackware 11.0 box from MythTV 0.20 to 0.21.
> After this I noticed that very often, when I want to play a DVD,
> mythfrontend crashes printing out the following:
>
> 2008-05-26 16:20:24.211 Compiler did not align stack variables.
> Libavcodec has been miscompiled and may be very slow or crash. This is
> not a bug in libavcodec,
> but in the compiler. You may try recompiling using gcc >= 4.2.
> Do not report crashes to FFmpeg developers.
>
>   

My understanding is there was some sort of feud between the FFmpeg devs 
saying there was a bug in gcc and the gcc devs saying there wasn't 
resulting in FFmpeg putting this message in there source. In reality it 
doesn't seem to be a real problem I was using gcc  3.x until quite 
recently with no problems. 

>   In fact, this diagnostic is printed out even when mythfrontend
> manages to load the DVD all right.
>
>   

You get this message whenever libavcodec is initialized I think.
 
>   Anybody know how to get around this? The gcc version in Slackware
> 11.0 is 3.4.6, and it used to work fine with MythTV 0.20. Also, I
> noticed that when building MythTV there is a libavcodec directory. Is
> this the one in the diagnostic? I am asking because I have an ffmpeg
> package installed in my box, which also has libavcodec.
>   

Yes it's the mythtv copy of ffmpeg that is showing this message. The 
only way to get rid of it is to upgrade gcc to 4.2 or later or hack the 
code.

Are you sure your crash is in ffmpeg? If you rebuild with debug info and 
get a  backtrace that should show us exactly where the crash is.
http://www.mythtv.org/docs/mythtv-HOWTO-22.html#ss22.2


Paul H.