Windows API IAudioMeterInformation

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C++

According to:
http://msdn.microsoft.com/en-us/library/dd316561(VS.85).aspx
The peak-meter values obtained from the methods in the IAudioMeterInformation interface are floating-point numbers in the normalized range from 0.0 to 1.0. For example, if a PCM stream contains 16-bit samples, and the peak sample value during a particular metering period is —8914, then the absolute value recorded by the peak meter is 8914, and the normalized peak value reported by the IAudioMeterInformation interface is 8914/32768 = 0.272.


However in real life the call never returns 0, but just a tiny fraction (4e-10 for example)

Is this ADC rumble and therefore nothing i can do about it or would changing soundcard get me 0.

I need 0 because my external amplifiers are controlled via an USB interface, my app polls peaklevels of the default endpoint and based on the endpoint switches on the on off the usbchannels and lighting up the amp.

I have second thread polling and if it has got a 0 during a given timeperiod switches the thing off.

I was counting on the fact that when an endpoint was actively engaged the rumble from the source would keep it life, but now i have this awful kludge were i set the parameters for 'is it active' for each audiosource since there is never 0.