[MPlayer-dev-eng] compiling mplayer with gcc 4.6, broken audio decoding

[Kazuo Teramoto]

2011/3/31 Thomas Orgis <thomas-forum at orgis.org>:
>
> Could you test if mpg123 (http://mpg123.org/current) has the same issue?
> Since mp3lib is a fork from past mpg123 code, this might lead to something.
> Although, there is an indication that this bug is specific to mp3lib / or
> the SSE part of which, both because mpg123 got rewritten SSE assembly and
> because
> https://sourceforge.net/tracker/?func=detail&atid=733194&aid=3249819&group_id=135704
> doesn't note anything about broken sound, just a compiler warning.
>

For me mpg123 is working (i.e. no high pitch as I have with mp3lib)

I compiled mpg123 1.13.2 with gcc 4.6.0, x86_64 (with sse), mplayer
compiled with gcc 4.6.0 too. (My proc is a Intel Core2 Duo P7350)

I'm with a limited network so I can get a gcc 4.5 version, sorry. But
I have some more info from gcc 4.6.0.

My normal build process (using the makepkg from Archlinux) compile the
file mp3lib/dct64_sse.c with the following flags:

--------------
cc -MD -MP -Wundef -Wall -Wno-switch -Wno-parentheses -Wpointer-arith
-Wredundant-decls -Wstrict-prototypes -Wmissing-prototypes
-Wdisabled-optimization -Wno-pointer-sign -std=gnu99 -O2 -march=native
-mtune=native -pipe -ffast-math -fomit-frame-pointer
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE
[....include -I, libs and other flags.....]
-c -o mp3lib/dct64_sse.o mp3lib/dct64_sse.c
--------------

Note the -O2 flag. I get the following warning when I run this cc[...]
line with either with -O2 or changing it to -O1 and relink mplayer:
--------------
mp3lib/dct64_sse.c: In function ‘dct64_sse’: mp3lib/dct64_sse.c:119:9:
warning: use of memory input without lvalue in asm operand 1 is
deprecated [enabled by default]
--------------
And in the two cases (O2/O1) I get the high pitch bug.

But if I change the -O2 to -O0, I don't get the warning AND I don't
get the very high pitch sound with mp3lib.

So, in summary compiling the mp3lib/dct64_sse.c with gcc 4.6 and -O0,
I don't get the high pitch sound with mp3lib.

(Is 6am, I hope i don't screwed any conclusion/test)

Best regards,
Kazuo.

-- 
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