See attached " AXIS SETUP FOR AUDIO WITH ONVIF.docx "
This KB describes in the attached document how to setup an Axis camera for ONVIF audio.
The AXIS Q1615 was used for this example. Other AXIS cameras may have similar setup.
Set Audio Settings
Setup the ONVIF Media Profiles
Results in Valerus showing mic on Valerus Resource list and the audio option on screen for the camera