25 lines
899 B
Swift
25 lines
899 B
Swift
import Foundation
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public enum AudioLevel {
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/// Reported for empty or silent buffers (log of zero would be -infinity).
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public static let silenceFloorDbfs: Float = -120
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public static func rmsDbfs(_ samples: [Float]) -> Float {
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samples.withUnsafeBufferPointer { rmsDbfs($0) }
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}
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public static func rmsDbfs(_ samples: UnsafeBufferPointer<Float>) -> Float {
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guard !samples.isEmpty else { return silenceFloorDbfs }
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var sum: Float = 0
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for sample in samples { sum += sample * sample }
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let rms = (sum / Float(samples.count)).squareRoot()
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guard rms > 0 else { return silenceFloorDbfs }
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return max(silenceFloorDbfs, 20 * log10(rms))
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}
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/// VU reading for a dBFS level, where `referenceDbfs` is 0 VU.
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public static func vu(fromDbfs dbfs: Float, referenceDbfs: Float = -20) -> Float {
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dbfs - referenceDbfs
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}
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}
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