A tip for mpeg2dec-0.4.0 on x86_64

Ken Moffat ken at linuxfromscratch.org
Sun Nov 6 14:26:32 PST 2005


On Sun, 6 Nov 2005, Ryan Twitchell wrote:

> I'm posting this so that if anyone else has the same problem, they will 
> hopefully find this message in the archives. I guess this would be the best 
> place to post this... maybe we need a new list: XBLFS!
>
> mpeg2dec-0.4.0 compiled ok on my pure64 machine but failed testing
> with some scary messages about push, pop, and mov assembly instructions.
> The failure comes as a result of optimizations set up in the file cpu_accel.c 
> for x86 processors. What effect this would have on actually using the library 
> after install I did not bother to find out.
>
> The following link is what helped me find a fix. The patch near the top of 
> the page isn't quite right for the 0.4.0b version of libmpeg2. I just added 
> #undef ACCEL_DETECT near the top of the concerned file (cpu_accel.c), and 
> that seemed to do the trick. I didn't try to modify the optimizations to 
> match my processor like in the link below, as I barley understand C, let 
> alone assembly on a 64-bit processor. Hopefully it won't result in *too* much 
> of a performance hit.
>
> http://sourceforge.net/mailarchive/forum.php?forum_id=729&max_rows=25&style=nested&viewmonth=200412
>
> I get to watch movies now!
> 	Ryan
>
>

  I'm using --disable-accel-detect when I configure on non-x86.

Ken
-- 
  das eine Mal als Tragödie, das andere Mal als Farce


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