[Libav-user] Runtime ARM Neon detection?

Carl Eugen Hoyos cehoyos at ag.or.at
Thu Apr 11 18:48:55 CEST 2013

Reuben Scratton <reuben.scratton at ...> writes:

> If I compile with -mfpu=neon then FFmpeg blows up 
> with SIGILL (ILLOPTPC) when run on a non-Neon CPU. 

> If I compile with -mfpu=vfvp3 then FFmpeg runs fine, 
> but presumably without the optimized code

Did you test this? (with a debugger)
I don't know but it seems very unlikely to me that a 
compiler option ("-mfpu=vfvp3") affects FFmpeg asm 


> Would it be possible for FFmpeg to detect Neon at runtime?

Looking at ff_dsputil_init_arm() in 
libavcodec/arm/dsputil_init_arm.c, that is exactly what it 
currently does.

Carl Eugen

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