Return the average volume of all channels that are included in the
* specified channel map with the specified channel position mask. If
* cm is NULL this call is identical to pa_cvolume_avg(). If no
* channel is selected the returned value will be
* PA_VOLUME_MUTED. \since 0.9.16
Return the average volume of all channels that are included in the * specified channel map with the specified channel position mask. If * cm is NULL this call is identical to pa_cvolume_avg(). If no * channel is selected the returned value will be * PA_VOLUME_MUTED. \since 0.9.16