[XviD-devel] A SSIM Plugin for XviD

[Johannes Reinhardt]

Hi,

skal schrieb:
>   Johannes and all,
>
>   
>> Message du 13/10/06 16:08
>> De : "Johannes Reinhardt" <Johannes.Reinhardt at uni-konstanz.de>
>>     
>>>> Message du 13/10/06 11:09
>>>>     
>>>>         
>>>>> The computation of ssim is slow. I tried to speed it up with a bit asm,
>>>>> but I have not coded in asm before. It would be great if some of the asm
>>>>> wizards could comment. It can be sped up more by reducing accuracy, by
>>>>> changing GRID to 2 or 4. But there seems to lurks a bug, as this 
>>>>> sometimes gives strange results. I will look into this.
>>>>>       
>>>>>           
>>>>   also: since MMX is mixed with floats, i fear some emms() were
>>>>   required, which i added. Could be an explanation for the strange
>>>>   behaviour.
>>>>     
>>>>         
>>>   there's a small bench for ssim functions included in xvid_bench.c too,
>>>   which shown no problem (unless the bench is itself broken, of course).
>>>   
>>>       
>> Attached is a patch that corrects a typo in xvid_bench.
>>     
>
>    ok, committed.
>    Note: attachments get stripped on this list, no exceptions.
>    You should rather inline the patch or upload it somewhere...
>   

ok
>> The SSE2 implementation of consim is not faster than the mmx version 
>> with all CPUs
>> (Pentium IV and Pentium M) I tested. Is there a chance to speed it up or 
>> should I
>> disable SSE2? Or is SSE2 perhaps faster on other CPUs?
>>     
>
>    I didn't had a deeper look at the ASM yet, because as said,
>    there's one thing to decide first: are you sure you want a 
>    square window for filtering? :)
>
>    bye,
> Skal
>
>   
hmm, I think the gaussian window will be _very_ slow. I will try to 
implement it as a extra mode, but I am not sure if it will be useful or 
usable. Perhaps it could be interesting to see how coarse the 
approximation used by most implementations is.

Regards,

Johannes