bit rate

Author: Gabriele Marcato

ios/Classes/methods/OnReadAudio.swift

@@ -20,35 +20,33 @@ public class OnReadAudio {
             var listOfSongs: [[String: Any?]] = Array()
 
             for uri in data {
-                // ipod-library://item/item.mp3?id=8746509304657824874
-
                 let url = uri.starts(with: "ipod-library://") ? URL(string: uri)! : URL(fileURLWithPath: uri)
 
-//                let id3Tag = try! ID3TagEditor().read(from: uri)
-//                let tagContentReader = ID3TagContentReader(id3Tag: id3Tag!)
-//                print(tagContentReader.title())
-
                 let file = try! AVAudioFile(forReading: url)
                 let fileFormat = file.fileFormat
-                let fileDescription = fileFormat.formatDescription
-//                let streamDescription = fileFormat.streamDescription.pointee;
-//                let bitDepth = streamDescription.mBitsPerChannel;
-//                let bitRate = streamDescription.mBytesPerFrame;
-                let settings = file.fileFormat.settings
-                let bitDepth = settings.first(where: { $0.key == AVEncoderBitDepthHintKey })?.value as? String ?? nil
+                let settings = fileFormat.settings
 
-                var info = self.toJson(
+                //  bithDepth of the song, available only with lossless formats:
+                // 'flac', 'wma', 'alac'
+                let bitDepth = settings.first(where: { $0.key == AVEncoderBitDepthHintKey })?.value as? String
+                let finalBitDepth: Int64? = bitDepth == nil ? nil : Int64(bitDepth!)
+
+                // try to read the song real bitRate
+                let bitRate = settings.first(where: { $0.key == AVEncoderBitRateKey })?.value as? String
+                // if cannot read it, calculate it approximately by: length / sampleRate
+                let finalBitRate: Int64? = bitRate == nil ? Int64(file.length) / Int64(fileFormat.sampleRate) : Int64(bitRate!)
+ 
+                let info = self.toJson(
                     channels: Int64(fileFormat.channelCount),
                     sampleRate: Int64(fileFormat.sampleRate),
-                    bitRate: Int64(file.length) / Int64(fileFormat.sampleRate),
-                    bitDepth: bitDepth == nil ? nil : Int64(bitDepth!)
+                    bitRate: finalBitRate,
+                    bitDepth: finalBitDepth
                 )
-
                 listOfSongs.append(info)
             }
 
-            // After finish the "query", go back to the "main" thread(You can only call flutter
-            // inside the main thread).
+            // After finish the "query", go back to the "main" thread
+            // (You can only call flutter inside the main thread).
             DispatchQueue.main.async {
                 self.result(listOfSongs)
             }

lib/details/models/audio_model.dart

@@ -244,6 +244,9 @@ class AudioModel {
   /// Return song [bitrate]
   int? get bitrate => _info["BITRATE"];
 
+  /// Return song [bitDepth]
+  int? get bitDepth => _info["BIT_DEPTH"];
+
   /// Return song [channels]
   String? get channels => _info["CHANNELS"];