Android: Amplitude value to Decibel value?

Question

I'm trying to get the decibel of noise being recored from mic on Android phone. I can get amplitude value and looking for the formula to convert it into decibel.

I use following function of MediaRecorder to get amplitude.

mediaRecorder.getMaxAmplitude() ;

In another question I found the following formula.

power_db = 20 * log10(amp / amp_ref);

amp is amplitude but not sure what's amp_ref.

Is there anyone knows the correct formula?

Answer 1

i think that is the correct formula. amp_ref is reference amplitude