[MPlayer-users] Fresh svn mplayer crashes on many ac3 streams

[Vladimir Mosgalin]

Hi Reimar Döffinger!

 On 2011.05.28 at 22:14:58 +0200, Reimar Döffinger wrote next:

> > The thing is, you see, this is default mode; on sandy bridge systems
> > "-march=native" with gcc 4.6 or higher
> 
> Huh? 4.6.0 is the latest version.
> And honestly, the answer is: you never, never ever use a .0 version of gcc for stuff you actually use.
> To my knowledge there hasn't been a single one without serious issues and MPlayer most of the time is affected.
> Slightly more useful: -fno-tree-vectorize probably should always be used as for FFmpeg, the only thing it does is make the code slower and cause bugs.

But it's latest stable version. Plus it's the only compiler in current
stable fedora release.

Anyhow it's a bit unfair to blame it on ".0" here, I think, since this
issue is related to avx as well and 4.6.0 was first stable release to
include avx support. It's, like, not gccs fault that avx support
appeared in .0 version and not some other..
(plus, we don't yet known if it's gcc problem or actual bug in ac3dec.c
code..)

I can turn off avx or ftree-vectorize, it's np to me - though I expected
some serious speedups from gcc 4.6.0 and avx support, like shown in some
phoronix benchmarks, for example
http://www.phoronix.com/data/img/results/intel_avx_gcc/6.png
http://www.phoronix.com/data/img/results/intel_avx_gcc/7.png

but I guess the real issue here is that ffmpeg's configure isn't
executed so ffmpeg's will to add -fno-tree-vectorize flag is ignored?

-- 

Vladimir