[Freeswitch-dev] VAD, TALK and NOTALK events

[Brian West]

On Feb 18, 2008, at 6:55 PM, Steve Underwood wrote:

> There is a pretty good free echo canceller at www.rowetel.com,  
> although
> FreeSwitch can't directly use it as it is GPL software. It does,
> however, mean that free and open workable algorithms for robust EC  
> do exist.
>
> VAD is different. It is still a research topic. You can see this from
> the way the VAD algorithms in things like G.729 have been revised over
> the codec's lifetime, as further research has been done. The  
> algorithms
> G.729 and AMR use are encumbered by patents, otherwise cloning them
> would be excellent start. VAD for speech recognition is relatively
> straightforward. When you can buffer the audio, and look forwards and
> backwards in time, it become much easier to identify the start and end
> of voice bursts. It becomes hard when you can only look back in a low
> latency scenario.
>
> Steve

Isn't that Echo canceler live in Kernel space?  If so then its fine.

/b