[speex-dev] Speex 1.1 is out

Tom Grandgent tgrand at canvaslink.com
Fri Sep 19 08:58:19 PDT 2003



Sounds great!!  I will definitely give these new features a try and 
let you know how it goes.  Every one of them (except for the narrowband 
mode) will be really useful to me.  I have a few questions after looking 
through the source code:

Echo cancellation:

1) What should I use for a filter length for speex_echo_state_init()?

2) I'm assuming I want to call speex_echo_cancel() on each incoming 
frame to be played back.  But, what do I pass for the parameters?  
I'm guessing that ref is the current outgoing frame, echo is the 
current incoming frame (which contains echo to be removed), out 
is the echo-cancelled frame to be played back, and Yout is the 
same signal as out but in the frequency domain.  Is this right?

Jitter buffer:

1) I'm assuming the timestamp should be in milliseconds.  (Does it 
matter?)

2) Do you anticipate any problems using VBR with the jitter buffer?  

Thanks again for all your work on Speex!

Tom

<p>Jean-Marc Valin (Jean-Marc.Valin at USherbrooke.ca) wrote:
> 
> Just to let you know I released 1.1:
> 
> This is an unstable release. It brings many new features, some of which
> are still experimental. The new features are:
> 
>       * a denoiser that removes most of the background noise and can be
>         used before encoding (available as --denoise in speexenc)
>       * adaptive gain control (AGC), which adjusts the volume to a
>         constant level (available as --agc in speexenc)
>       * echo cancellation (experimental, only available from libspeex)
>       * A jitter buffer which handles packet buffering for VoIP
>         applications (experimental, only available from libspeex)
>       * an improved narrowband mode at 4.8 kbps (nonstandard mode, only
>         availablefrom libspeex for applications that don't require
>         compatibility with other software)
> 
> Please test this release and report bugs. If youÿre developing a VoIP
> application, you are encouraged to try out these new features which will
> help increase the quality of the speech transmitted
> 	
> 	Jean-Marc
> 
> -- 
> Jean-Marc Valin, M.Sc.A., ing. jr.
> LABORIUS (http://www.gel.usherb.ca/laborius)
> Université de Sherbrooke, Québec, Canada
> 
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