Dear All,
I write to ask if it is possible to assert a GPIO or output logic 0 during playback. I use I2S from Raspberry Pi to feed audio data to AK4399. To playback the sampling rate from 44.1Khz to 96khz, at least two clock frequencies are required, namely 22.x khz and 24.x khz. I have built a clock module with selector of two silicon oscillators. All I need to do is to automatically detect the song’s sampling frequency and select the clock source at clock module via GPIO. Please advise if this can only be made through modifying the code of mpd. Many thanks! 
-steve