Returns the number of output channels this device has, or zero if there's none, or -1 if it's enforced at audio
spec request.
NOTE: Depending on the backend, devices' inputs and outputs (or even different inputs and outputs) might show up
as different devices.
Returns the number of output channels this device has, or zero if there's none, or -1 if it's enforced at audio spec request. NOTE: Depending on the backend, devices' inputs and outputs (or even different inputs and outputs) might show up as different devices.