[XviD-devel] About xvid source assembly language optimize(why it does not work?)
michael at xvid.org
Tue Nov 18 18:05:28 CET 2008
make sure you really compiled xvid with assembly optimizations enabled. You
need yasm or nasm present - or otherwise xvid will be compiled with c-code
Also note that the -m option will write out data to your disk. It might be
that more time is spent on I/O than on the actual decoding. In that case,
asm and noasm options could seem to perform similar.
Quoting ?? <bing.li at autosoft.com.cn>:
> Dear Everybody:
> I download the xvid 1.1.3 source code , and i compiled the
> source under Fedora Core 8.
> Then I compile xvid_decraw.c.
> And I run with the command:
> ./xvid_decraw -i input.m4v -m
> then it work well, and output the bitmap file. but it is rather slow.
> Then I use the command below:
> ./xvid_decraw -i input.m4v -asm -m
> Hence I think i used -asm option , the decoding speed should be
> But .... I find that the result is unchanged with the non-asm
> execution result .
> input.m4v is a raw 720x568 mpeg4 video sequence, .
> I wonder whether the -asm option worked!
> So i test the fdct and idct, they have been assigned to
> fdct_mmx_skal and idct_mmx respectly.
> But why it does not accelerate?
> So i use a small script to test the fdct_c and fdct_mmx_skal.
> To run 1000000 times ,
> the fdct_c consume 2.7 seconds and fdct_mmx_skal need 0.8 second
> on my computer.
> It seems that asm code should be much faster. But why xvid
> decoding can not be speeded up?
> Thanks very much !
> Ice Lee
> XviD-devel mailing list
> XviD-devel at xvid.org
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