[FFmpeg-user] How to configure x86_64

[Carl Eugen Hoyos]

David Favor <david <at> davidfavor.com> writes:

> Carl Eugen Hoyos wrote:
> > Elliott Balsley <elliottbalsley <at> gmail.com> writes:
> > 
> >> ARCH                      x86 (generic)
> > 
> > This only says you did not request optimization 
> > for a specific cpu (like --cpu=corei7-avx)
> 
> The best way to determine exact arch type is to introspect
> the executable using the file command.

Unfortunately, it is exactly the other way round;-(

file can be outdated (even for files created with the 
system compiler on a proprietary operating system, 
happened to me this week).
The following always work, depending on the architecture:
$ grep X86 config.h
$ grep PPC config.h
$ grep SPARC config.h
Telling you if you are compiling for 32 or 64 bit.

Only arm is more complicated:
$ grep ARM config.h
$ grep AARCH config.h

> David-Favor-iMac> file $(which ffmpeg)
> /david-favor-tools/osx-10.9/bin/ffmpeg: Mach-O 64-bit x86_64 executable

(This is exactly what failed for me this week for a 
slightly more extraordinary executable / target 
architecture.)

Carl Eugen