Re: [mpeg2-dev] Crashes in sse2_idct x86_64

[Matthew M. <mmc...@gm...>]

Hi John,

I revisited the problem early this year, and while I made a little more
progress, I didn't solve it.

I did make find that changing line 100 in mpeg_internal.h from:

int16_t DCTblock[64] ATTR_ALIGN(64);
to
__declspec(align(64)) int16_t DCTblock[64];

stopped it crashing in _mpeg2_idct_copy_sse2() and it actually started
producing images.
But, alas, the images were corrupted with vertical streaks.

But that would be my suggestion for a starting point.. check the data
alignment.

Matt
ps.
I never managed to even get close to compiling  idct_mmx.c
and motion_comp_mmx.c in Visual Studio.
I then tried using the sse2 functions that come with MediaPlayerClassic.
I remember this also almost worked, but suffered from different kinds of
image defects.
In the end I found versions of libmpeg2-0.dll and mpeg2.lib in the GStreamer
project that had been compiled with SSE2, and just went with those.


On 31 May 2011 00:02, John Stebbins <ste...@je...> wrote:

> Have there been any new developments on this problem?
> http://sourceforge.net/mailarchive/message.php?msg_id=25140766
>
> I am seeing similar (if not identical) behavior from libmpeg2 compiled with
> the mingw64 cross tools for fedora
> (available here http://build1.openftd.org/mingw-w64/)
> After disabling gcc optimizations and enabling debug, gdb indicates the
> crash happens in sse2_idct at the first movdqa_m2r.
>
> There are also reports of similar crashes in sse2_idct due to recent gcc
> 4.6 changes.
> http://comments.gmane.org/gmane.linux.mandrake.bugs/201430
> The patches in this thread fix the problem on fedora 15 where this is
> reproducible, but not for mingw64 builds
> unfortunately.
>
>
>
>
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