Refactor(AVAudioFile): move logic into extension and analyze function

Author: bastienFalcou

Example/Pods/Pods.xcodeproj/project.pbxproj

@@ -0,0 +1,34 @@
+//
+//  AVAudioFileExtensions.swift
+//  Pods-SoundWave_Example
+//
+//  Created by Bastien Falcou on 4/21/19.
+//
+
+import AVFoundation
+
+extension AVAudioFile {
+    func buffer() throws -> [[Float]] {
+        let format = AVAudioFormat(commonFormat: .pcmFormatFloat32,
+                                   sampleRate: self.fileFormat.sampleRate,
+                                   channels: self.fileFormat.channelCount,
+                                   interleaved: false)
+        let buffer = AVAudioPCMBuffer(pcmFormat: format!, frameCapacity: UInt32(self.length))!
+        try self.read(into: buffer, frameCount: UInt32(self.length))
+        return self.analyze(buffer: buffer)
+    }
+
+    private func analyze(buffer: AVAudioPCMBuffer) -> [[Float]] {
+        let channelCount = Int(buffer.format.channelCount)
+        let frameLength = Int(buffer.frameLength)
+        var result = Array(repeating: [Float](repeatElement(0, count: frameLength)), count: channelCount)
+        for channel in 0..<channelCount {
+            for sampleIndex in 0..<frameLength {
+                let sqrtV = sqrt(buffer.floatChannelData![channel][sampleIndex*buffer.stride]/Float(buffer.frameLength))
+                let dbPower = 20 * log10(sqrtV)
+                result[channel][sampleIndex] = dbPower
+            }
+        }
+        return result
+    }
+}

SoundWave/Classes/AVAudioFileExtensions.swift

@@ -150,22 +150,6 @@ public class AudioVisualizationView: BaseNibView {
 		return self.meteringLevelsClusteredArray
 	}
 
-    // PRAGMA: - Analyze Sound File
-
-    private func buffer(url: URL) {
-        do {
-            let track = try AVAudioFile(forReading: url)
-            let format = AVAudioFormat(commonFormat:.pcmFormatFloat32,
-                                       sampleRate:track.fileFormat.sampleRate,
-                                       channels: track.fileFormat.channelCount,
-                                       interleaved: false)
-            let buffer = AVAudioPCMBuffer(pcmFormat: format!, frameCapacity: UInt32(track.length))!
-            try track.read(into : buffer, frameCount:UInt32(track.length))
-        } catch {
-            print(error)
-        }
-    }
-
 	// PRAGMA: - Play Mode Handling
 
 	public func play(for duration: TimeInterval) {