System : Linux raspberrypi 4.14.79-v7+ #1159 SMP Sun Nov 4 17:50:20 GMT 2018 armv7l GNU/Linux
A Bluetooth A2DP source goes into a Pulse Audio sink which is going into the pulse audio equalizer module, gui for that is qpaeq, and then outputting to a usb interface.
The sound quality is perfectly fine, apart from these persistent overruns. They cause a momentary pause and jitter in the audio stream. I need to remove them, without removing the equalizer module from the signal chain as there are no other equalizers that I have found which run on RPI3B+.
They seem to occur when the re-sampler rate drops below a certain threshold. This then appears to cause a an imperceptible rewind of the audio input and reset the sample rate counter. From the logs it would appear that the sample rate count down continues again after this reset and repeats until it hits another overrun.
/etc/pulse/daemon.conf I have tried changing the re-sampler, but this has no effect on the issue. The
default-fragments parameter in this file does have an effect in that when I doubled the number the period of time between these overrun events is much longer, unfortunately the period of the skip is also slightly increased and is more perceptible even though they are less frequent (30 sec vs 10 sec).
The increase in
default-fragments also massively increases the latency in the output.
Here is a pulse audio output log of the issue.
Here is my pulse audio