Andrew Mindrin wrote: > Tim Roberts wrote: No, he quoted that. > > 3. current volume (in dB) + 20 * log10( peak value ) > > I agree with your formula for PPM meter, but it doesn't correspond to > low-range of > IAudioEndpointVolume::GetVolumeRange. Can you give an example where it doesn't correspond? > 1. Current Volume (in dB) * Peak Value So if the current volume is -12 dB, and the peak value is at 0.5, the meter would show -6 dB? > This is VU meter formula. > > 2. 20 * log10( peak value ) > > This is PPM meter formula. The difference between VU meters and PPM meters is in the rise and fall times, not in the mapping of input values to the display. > It has no correlation to the range of volume levels returned by > IAudioEndpointVolume::GetVolumeRange. Yes, because the current volume doesn't appear in this formula; it implicitly assumes that peak = 1.0 is at 0 dB. Regards, Clemens ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/