[Freeswitch-users] Hardware echo cancellation.

David Knell dave at 3c.co.uk
Thu Nov 19 07:54:55 PST 2009

Hi Brian,

> It just doesn't belong in user space or kernel space in the machine  
> for true performance you should do it in hardware... I'm pretty sure  
> the poor box would die if you tried it on 32 E1's at the same time.

Disagree somewhat.  The challenge that echo cancellers further from the
hardware face is having some idea of the size of the buffers between the
canceller and the wire; provided that this is known, or is small in
comparison to the canceller's tail length, it can, in principle, go
anywhere.  All other things being equal, the right place for a software
EC is in user space: can be done in a cross-platform way, can use
FPU/MMX/SSE without guilt and voodoo, etc.  And there is no reason why
the same algorithm would perform differently if implemented in
"hardware" or on the host CPU.

And the OP only needed four E1s..


> /b
> On Nov 18, 2009, at 5:39 PM, David Knell wrote:
> > For the sort of box you're talking about (quad core++), this isn't  
> > lots;
> > it's hardly any..
> >
> > --Dave
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