[Ffmpeg-devel] segfault: ff_fdct_sse2

Rich Felker dalias
Wed Jun 15 04:47:52 CEST 2005

On Tue, Jun 14, 2005 at 06:46:27PM -0700, RayLing Hwang wrote:
> Hi, 
> I have stuck on this for two weeks. Someone please help out. Thansk in advance.
> 1. I wrote a small program to extract partial frames out mpeg1/2 for video preview.
>     I basically followed apiexample.c and output_example.c.
> 2.   I have compliled ffmpeg 0.4.9-pre1 with Msys/mingw with configure --enable_shared
> 3. It runs ok on windows 2000, but crashed on XP home-edition. But we need it to be run
> on XP home.
> 4. The crash seems to be related to program address, by changing unimportant input options(e.g. change  log file name from abc.log to aaaaaaaaaaaaaaaaaa.log ) it may run
> ok sometime. 
> 5. change log of ffmpeg for this release says "fdct sse2" --- is it a fix for problems like mine?
> 6. I run ffmpeg to convert our mpg files, it crashes depending on input option.
>     eg,  A. ffmpeg -target ntsc_vcd A.mpg runs ok 
>           B. ffmpeg -target ntsc_vcd B.mpg crashes 
>                but ffmpeg -target ntsc_vcd -s 352x288 B.mpg runs ok
> 7. decoing is fine, ffplay plays all our mpg files ok.
> 8. I have run about 10 mpeg files, all die at the same place.
> 8. Attached information from gdb

You must enable memalign hack. Windows has broken memalign which
cannot ensure that data is properly aligned for sse instructions.
Alternatively just disable sse.


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