Changes the input gain to the specified value.
- iOS 6.0+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
The new gain value, which must be in the range
0represents the lowest gain setting and
1represents the highest gain setting.
On input, a pointer to an error object. If an error occurs, the pointer is set to an
NSErrorobject that describes the error. If you do not want error information, pass in
YES if the new gain value was set successfully,
NO if it was not.
Before calling this method, check the value in the
input property to make sure the input gain level is settable for the current inputs.