[FFmpeg-user] ffmpeg-1.0 make failed on Fedora x86_64

[Carl Eugen Hoyos]

Reindl Harald <h.reindl <at> thelounge.net> writes:

> >>  --extra-cflags="-O3 -march=corei7 -mtune=corei7 -mmmx 
> >> -msse2 -msse3 -msse4.1 -msse4.2 -fopenmp -mfpmath=sse
> >> -fstack-protector --param=ssp-buffer-size=4 -pipe 
> >> -D_FORTIFY_SOURCE=2 -fexceptions" \
> > 
> > There are two possibilities:
> > Either this is useful (and helps performance), then 
> > it should be made default. At least a bug report 
> > would be nice.
> 
> WHY should it be a DEFAULT?
> 
> that i have a corei7 does not mean anybody has
> these are simply compiler flags enabling gcc-optimization

I was more thinking of "-O3 -fopenmp -mjpmath" etc.
(that I suspect hurt performance or at least unneeded).
But I wonder why -mtune=native is not the default...
(I thought it is, that is why I asked about the options.)

> >>  --enable-static \
> > 
> > This looks unneeded
> 
> the RPM is for a STATIC build

this is exactly my point:
FFmpeg does compile static libraries if not 
told differently, so this option only clutters 
output (same for all other "unneeded" options).

> >>  --enable-runtime-cpudetect \
> > 
> > Could you explain why this is useful?
> 
> why not?

Iirc (and only if), this disables the optimizations 
you try to set above. (This is at least what it 
did for MPlayer once upon a time, I am not sure if 
there was ever a good reason to change the meaning.)

Carl Eugen