[mythtv] Mythtranscode Segfaulting
Michael T. Dean
mtdean at thirdcontact.com
Wed Apr 25 14:47:37 UTC 2007
On 04/25/2007 12:55 AM, Andy Speagle wrote:
> So.. let me take another crack at this... I've downgraded my QT to
> v3.3.4-r8on Gentoo... and my Mythtranscode is continuing to
> segfault... here's the
> latest gdb output:
> mythtv ~ # gdb mythtranscode -x gdbcommands
> (no debugging symbols found)
... Really, a backtrace on a build compiled with debugging support is
much more useful. (And since you're using Gentoo, it should be easy to
get one next time.) ...
> Program received signal SIGFPE, Arithmetic exception.
> [Switching to Thread -1258027312 (LWP 9518)]
> 0xb7afb42e in VideoOutput::ApplySnapToVideoRect () from
However, in this case, it's relatively clear what's likely happening
even without specifics. It looks like you're getting a division by zero
(with "ydiff / display_video_rect.height()" and/or "xdiff /
display_video_rect.width()"). While it would be possible to just check
for zero (or add 1 to the width/height, as in the example patch below)
to prevent the segfault, most of the code in VideoOutput relies on
non-zero width and height, so you're likely to just get a segfault
elsewhere if you don't fix the problem (i.e. figure out why
display_video_rect isn't getting properly initialized).
I haven't looked to see how display_video_rect gets its values, but
perhaps someone who knows VideoOutput/mythtranscode can chime in with
reasons yours wouldn't have been initialized properly--giving it 0 for
height or width. Guessing... perhaps your transcoding profile is
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