[Ffmpeg-devel] Segfault when encoding MPEG with MMX support

Michael Niedermayer michaelni
Sun Jul 10 21:23:00 CEST 2005


On Sunday 10 July 2005 18:35, Tobias Grimm wrote:
> Hi!
> I have an application that encodes still images as MPEG2 to be viewed by
> a DVB card. With the update to Debian Sarge the application is broken,
> so I tried out the latest ffmpeg CVS snapshot (2005-07-10).
> Unfortunately, this does not solve the problem. I always get a segfault,
> when avcodec_encode_video() is invoked (see backtrace at the end). Only
> if I compile ffmpeg with --disable-mmx, it works.
> I'm using gcc 3.3.5 / libc6 2.3.2.
> Any ideas, what may be going wrong? What can I do to find the source of
> the problem?

well, try to recompile libav* or just the involved files (mpegvideo_mmx*) with 
-O1 and post the gdb output from

disass $pc-32 $pc+32
info all-registers

also try a make distclean if you didnt already though it probably wont help 
and ensure that all images you pass into libav are aligned at 16 byte 


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