An array of integers indicating from which input to derive each output.
- iOS 9.0+
- macOS 10.11+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 3.0+
The array size equals the number of output channels. Each element's value is the input channel number, starting with zero, that is to be copied to that output.
A negative value means that the output channel will have no source and will be silent.
Setting a channel map overrides channel mapping due to any channel layouts in the input and output formats that may have been supplied.