[gst-devel] Volume High/Low Pass Filters, AGC filter

[Stefan Kost]

Am 07.01.2011 22:09, schrieb Wes Miller:
> 
> I looked through the list returned by gst-inspect and in the list of all
> plugins on the website and I  don't see quite what I'm after.
> 
> First, Is there a stage to do volume pass filtering?  Idea is to sniff audio
> streams looking for low volume passages and replace them with silence or
> whitenoise af a fixed volume.  

Replacing it with silence would be a noise-gate and I am sure there is one in
the form of a ladspa plugin. But then I am wondering, if you are actually
looking for a comfort noise generator?

> 
> Secondly, is there an audio AGC (automatic gain control) filter?  Following
> a 300 to 3000 Hz band pass filter and  an element that can do the volume
> pass operation, this element should clean audio (speech over noise mostly)
> to control highly variable background noise and maximize the speech quality. 
> Think of a microphone in use in an outdoor industrial setting where machines
> or heavy trucks start and stop continually.  First select only the usual
> voice band, flatten static, wind noise, motor/engine rumble, etc. then
> modify the overall volume to a pleasant level.

I don't think we have that one. Wanna try writing one? We have filters and e.g.
the level element. Mix well together and add whats missing :)

Stefan

> 
> Yes, of course this would make more sense as a hardware process, but I
> though I might be able to use it to assist existing hardware or to augment a
> hardware solution.
> 
> Wes