Oculus GO - Best way to pull mic input

Unreal has an AudioCapture component with a back-end using rtAudio, which supports Windows, Mac and Linux, but not android. I've looked around and couldn't seem to find a way other than using the native sdk to pull the microphone data from the Oculus Go.

So I wrote a little component that does the following:

#include "OculusNativeMicComponent.h"


void UOculusNativeMicComponent::Start()
{
	micHandle = ovr_Microphone_Create();
	ovr_Microphone_Start(micHandle);

	// We also need to determine the maximum size of the buffer
	pcmSize = 2400;
}

void UOculusNativeMicComponent::Stop()
{
	ovr_Microphone_Stop(micHandle);
}

float UOculusNativeMicComponent::GetAmplitude()
{
	QUICK_SCOPE_CYCLE_COUNTER(STAT_GetAmplitude);

	// Pull correct data into buffer
	size_t capturedSize = ovr_Microphone_GetPCM(micHandle, pcmBuffer, pcmSize);

	
	float max = 0.f;
	float amplitude = 0.f;
	for (size_t i = 0; i < pcmSize; i++)
	{
		// Since the format of the stream is in 16-bit fixed point, we want to place in range of 0 .. 1.0 (float)
		float sample = abs(pcmBuffer / 32768.0f);

		if (sample > max)
			max = sample;

		amplitude += sample * sample;
	}

	amplitude = sqrt(amplitude / pcmSize);
	return amplitude;
}

Unfortunately, pcmBuffer is always filled with zeros all the way through, before it even goes through any processing. Does anyone have any experience using ovr_Microphone_GetPCM?

Is there any other setup that would be required?