Amplitude Levels
Amplitude level measurements include peak and average RMS sample values encountered over the measurement interval. For some of the lower bit rate and bits of resolution codecs, peaks are averaged and reported on a change of the average. For the highest quality settings, a change may be reported on the first occurrence. The measurement intervals are typically 0.05 to 0.1 sec representing 10 to 20 reports per sec. The peak values are commonly used to drive user interface volume level indicators.
The minimum change that will trigger events is configured according to the audio stream specific parameters in effect, but it is generally between 2 to 4 dB.