[Ffmpeg-devel] patch: altivec optimizations for h264 decoder

[Derk-Jan Hartman]

On 6-feb-2006, at 17:31, Derk-Jan Hartman wrote:
> I'll test it in a couple of hours on a Dual G5. (If no one did  
> before I did of course).
>
> DJ

I tried the patches, but they don't work for me.
These are the effects that i am seeing.

http://veda.student.utwente.nl/~hartman/avcaltivec.png
http://veda.student.utwente.nl/~hartman/avcaltivec2.png

Darwin veda.student.utwente.nl 8.4.0 Darwin Kernel Version 8.4.0: Tue  
Jan  3 18:22:10 PST 2006; root:xnu-792.6.56.obj~1/RELEASE_PPC Power  
Macintosh powerpc

gcc version 4.0.0 (Apple Computer, Inc. build 5026)

DJ


> On 6-feb-2006, at 14:07, Romain Dolbeau wrote:
>
>> Michael Niedermayer wrote:
>>
>>> mixing declarations and statements, romain is this an issue for  
>>> ppc-asm or do
>>> all compilers which support ppc-asm support this too?
>>
>> They probably do. It would be intesrting to know what OS and compiler
>> the author of the patches used (I don't have linux/ppc anymore).
>>
>>> romain please review and test, you are the ppc maintainer
>>
>> I am ? damn, more responsabilities :-/
>> I can't test, as I don't have a sample, and if I had,
>> I don't have a machine fast enough for 1080p anyway
>> (the G4 isn't the fastest CPU around...)
>>
>> Patch 1 : nothing to add, except that gcc register allocator is  
>> probably
>> going to hate ff_h264_idct_add_altivec_mat
>>
>> Patch 2 : in PREFIX_h264_qpel4_hv_lowpass_altivec, why use
>> VEC_LOAD_UNALIGNED_CHECK ? tmpbis is computed from tmp
>> (comments -> assumed aligned) and tmpStride (comments ->
>> multiple of 16), so it has to be aligned.
>>
>> Patch 4 : is put_pixels8_altivec really faster than the C
>> version ? there's not computation whatsoever, and with the
>> need to load the destination block to insert the new
>> data, it may be slower to use AltiVec than regular C code.
>>
>> I'm a little bit short on time to be able to make a more
>> thorough investigation, sorry
>>
>> -- 
>> Romain Dolbeau
>> <romain at dolbeau.org>
>>
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