Hi everybody,

I need to find a way to alter the audio streaming from a microphone in the
system, transparently to the application that uses the device. I want to
apply some effects on the audio from the microphone (like reverb noise
cancellation, etc.) and have the globally available in the system.

I've tried to filter the audio device in the system with an upper filter
driver, but all I get are the properties for the audio format and
capabilities, it seems that the audio stream somehow skips the driver stack.
I am getting the frames only if I open the device from "WDM Streaming
Capture Devices" when I build the audio graph. From what I've read, this is
the way the audio stack was designed to work.

Is there a way to intercept the audio stream before it gets to the
application that uses the device? Does Windows provide a way to implement a
filter (user mode or kernel mode) for this purpose?

Could anyone give me some suggestions?
Thanks,
Bogdan Dinu

Hi Bogdan,
Is it on Vista or XP? for your application on Vista, System Effect Audio
Processing Objects is the right choice.


"Bogdan Dinu" wrote:

Both XP and Vista.
It seems that there isn't a solution that would work on both XP and Vista.
For XP, GFX filters seem to be the equivalent of SAPOs, but I don't know if
they would work for this.

I'll study the System Effect Audio Processing Objects further , and maybe
I'll get some results at least for Vista.

Thanks,
Bogdan

"King" <King@discussions.microsoft.com> wrote in message
news:A1DABB98-4896-4B34-B683-BCD6CA3B1852@microsoft.com...