Returns the average power for a given channel, in decibels, for the sound being played.
- iOS 2.2+
- macOS 10.7+
- tvOS 9.0+
- watchOS 3.2+
The audio channel whose average power value you want to obtain. Channel numbers are zero-indexed. A monaural signal, or the left channel of a stereo signal, has channel number
A floating-point representation, in decibels, of a given audio channel’s current average power. A return value of
0 dB indicates full scale, or maximum power; a return value of
–160 dB indicates minimum power (that is, near silence).
If the signal provided to the audio player exceeds ±full scale, then the return value may exceed
0 (that is, it may enter the positive range).
To obtain a current average power value, you must call the
update method before calling this method.