Re: yuvdeinterlace

stefan <[email protected]>
Newsgroups gmane.comp.video.mjpeg.devel
Message-ID <[email protected]>
Scott Smith schrieb:
> On 2/23/07, stefan <[email protected]> wrote:
>   
>> Could someone explain me, why it must be aligned to 16 bytes? 8 bytes I
>> would understand (quad-word) but 16?!? Is this really necessary?
>>     
>
> I can't for Altivec, but I can for sse...
>   
hmm, well, my sentence was not well formulated... My problem in 
understanding is not correlated to the potential speedup of certain 
opcodes used. It is more related to the fact, that all modern 
block-based-codecs use 8x8 pixel-blocks and if you do an overlapped 
search...

OK, I can come arround that thing by using psad_sub22() instead, as this 
one just can not be forced on 16 byte boundaries... :-) (it is an 8x8 
pixel-block-SAD...) But this will mean that there is no overlap anymore 
(I just do not know for sure if it will work reliably without...)

cu
Stefan


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