[Ffmpeg-devel] Illegal instruction in ff_fdct_sse2 () from libavcodec.so.51

Guillaume Poirier gpoirier
Tue Jul 18 14:58:10 CEST 2006


Hi,

Matthew Houliston wrote:

> Le mardi 18 juillet 2006 ? 11:03h, poirierg <at> gmail.com a ?crit :
> 
>> Can you post the output of /proc/cpuinfo? Otherwise what's your cpu?
> 
> Thanks Guillaume. FreeBSD doesn't have /proc/cpuinfo, but I can give you
> this :
> 
> root at www:~# grep ^CPU /var/run/dmesg.boot
> CPU: Intel(R) Xeon(TM) CPU 2.80GHz (2800.11-MHz 686-class CPU)

Ok, your CPU does indeed support SSE, but your OS doesn't. At least,
that's what Google tells me:
http://lists.xiph.org/pipermail/flac-dev/2005-January/001749.html
http://knowledgehub.zeus.com/faqs/2005/07/01/howto_recompile_a_freebsd_kernel_with_ss

Could you maybe try to compile and post the output of the attached
program? It should print the same output as what linux's /proc/cpuinfo
I bet it lists SSE as available, but you can't used it because of lack
of OS support.
I don't know how this could be checked on runtime... it would be nice
if FFmpeg wouldn't crash... in such case, but I guess you've exposed a
bit of an unprobable corner case right there...

> Apologies if I broke anybody's message threading - just subscribed, so
> no message ID...

It shows up alright on my mailer ^^.

Guillaume
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