[MPlayer-users] not aligned stack variables? (old gcc)

Vladimir Mosgalin mosgalin at VM10124.spb.edu
Wed Jan 26 02:45:59 CET 2011


Hello everybody.

I compiled mplayer on Solaris 11 express system (x86-64), where latest
gcc is 3.4.3 (csl-sol210-3_4-20050802). Mplayer now prints big fat
warnings like

----
MPlayer SVN-r32815-3.4.3 (C) 2000-2011 MPlayer Team

Playing nightmare_castle.mpeg.
MPEG-PS file format detected.
VIDEO:  MPEG2  720x480  (aspect 2)  29.970 fps  3200.0 kbps (400.0
kbyte/s)
Load subtitles in ./
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Selected video codec: [ffmpeg2] vfm: ffmpeg (FFmpeg MPEG-2)
==========================================================================
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
AO: [null] 48000Hz 2ch s16le (2 bytes per sample)
Starting playback...
Compiler did not align stack variables. Libavcodec has been miscompiled
and may be very slow or crash. This is not a bug in libavcodec,
but in the compiler. You may try recompiling using gcc >= 4.2.
Do not report crashes to FFmpeg developers.
----


Well it's not that easy to follow advice, because gcc >= 4.2 is hard to
get (need to compile new mpc/binutils/gcc/etc from scratch, as people
say that gcc4 from blastwave built for solaris 8 has problems when
compiling ffmpeg/mplayer on solaris 10/11).

There are lots of reports in google about similar issue in ffmpeg, but
no real answer if it's dangerous or not - its like one third people are
saying that gcc 3.4.6 helps (but nowhere to get it..), one third of
people are saying to get gcc 4.x, one third saying to ignore..


I'd like to ask if any real unnoticeable problems can arise from this
warning, like, if it crashes, I'll notice, but can there be any other
bad consequences except for crash? Is it possible to solve this problem
with gcc3, or gcc before 4 is absolutely not supported by current
mplayer? 
And third question, will recompiling with Sun Studio 12.2 instead of gcc
help, and whether it's favoured way of compiling mplayer under solaris?
(I don't have studio installed atm, but getting it will be easier than
compiling gcc 4 from scratch..)

-- 

Vladimir


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