[Asterisk-Dev] Echo cancellation on GPU

[SteveK]

On Sep 25, 2005, at 3:21 PM, John Todd wrote:

> At 8:09 PM +0200 on 9/25/05, steve at daviesfam.org wrote:
>
>> Hi,
>>
>> I've been thinking off and on about echo cancellation and the use  
>> of a GPU
>> board to run it.
>>
>> The idea is to use "inexpensive" commodity graphics card in the  
>> box, and
>> offload the "dsp"-style work to the GPU.
>>
>> I just now came across this new research paper in which an FIR  
>> filter is
>> implemented on a GPU:  http://www.ecsl.cs.sunysb.edu/fir/fir.ps
>>
>> FIR filter is at the core of most echo cancellation algorithms -  
>> so this
>> looks like a head-start on such a project.
>>
>> Dunno if you have comments, Steve Underwood?
>>
>> Regards,
>> Steve
>>
>
>
> Just as a reference, there was some mumbling about this earlier in  
> the year, but no conclusive comments either way:
>
> http://lists.digium.com/pipermail/asterisk-dev/2005-January/ 
> thread.html#8863
>
> I don't have a link offhand, but I remember someone being very  
> dismissive of the idea with a set of reasonable arguments.   
> However, I also know that ignoring people who tell you things are  
> impossible is one of the best things a programmer can do...
>

IIRC, the concerns were about the ability to move the data on and off  
quickly enough -- because in general, you have a lot of bandwidth  
_to_ the GPU, but not as much bandwidth back..

But, I think that the reason nobody did it was mainly because there  
wasn't anyone qualified to do it that was willing to try it out :)

Indeed, the echo cancellers in zaptel are FIR filters.

-SteveK


> Additionally:
> http://www.ecsl.cs.sunysb.edu/fir/  (general project)
> http://lists.digium.com/pipermail/asterisk-users/2004-June/049298.html
> http://gpgpu.org/forums/viewtopic.php? 
> p=3583&sid=8509723b6c1ba42424fd68149c71b0b6
>   http://www.bionicfx.com/info.html
>   http://www.pjwstk.edu.pl/~s1525/index.html#msc
>
>
> JT
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