preferredVolume
The volume to prefer for playback of the output’s audio data.
Declaration
var preferredVolume: Float { get set }Discussion
The default value for audio data is 1.0, which indicates typical playback level. Set the value for this property in the range of 0.0 to 1.0. For nonaudio media, the default value is 0.0.
You can’t set this value after writing starts.