[linux-audio-dev] Re: LADSPA_Data audio values

Iain Young iain at g7iii.net
Fri Dec 22 21:40:27 UTC 2006

Hi Ben,

You Wrote:
> 1)  0.0f indicates silence, not -1.0f
> 2)  A microphone input will have some noise on it, you'll need an 
> adjustable threshold value which separates the "on" state from the "off"
> 3)  You can't do this on a sample-by-sample basis, you need some time 
> averaging:
> 3a)  you need to implement a rectified, running average value of all 4 
> inputs
> 3b)  you'll need to mix the values of all four buffers into the output, 
> with a smoothly changing level control on each input controlled by the logic
> 4)  Make sure the "decay" of the envelope is kinda long ...this will 
> keep a speaker from getting cut off if someody else coughs or whatever

Thanks for the additional feedback, The sources are actually all software
rather than any hardware microphones. I also have the gate plugin inline
with each of the 4 inputs, prior to feeding them into my plugin. 

It was really written, so I could have music, ISS Audio, Gaim notifications
etc, and If any of the Astronauts say something, or someone logs on MSN/IRC,
then any music I'm listening to gets overridden.

It currently works for me, but I need to do some cleanup, and do a
stereo version. I'm also thinking of a modified version to handle
the situation where I'm outputting audio to my 5.1 Home Theatre

I had named it 'PrioMux' (Priority Multiplexer), but if the correct
term is 'Auto Mixer', then I can easily change it before release.

Best Regards


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