feat: Add smoothTransition option for AudioVisualizer. (#773)

* feat: Add smoothTransition option for AudioVisualizer.

* Fix smoothTransition option issues (#774)

* Use smoothingTimeConstant override on the web

* Fix Kotlin assignment

---------

Co-authored-by: Catalin Voss <[email protected]>

Author: cloudwebrtc

android/src/main/kotlin/io/livekit/plugin/LiveKitPlugin.kt

@@ -58,6 +58,7 @@ class LiveKitPlugin: FlutterPlugin, MethodCallHandler {
     var audioTrack: LKAudioTrack? = null
     val barCount = call.argument<Int>("barCount") ?: 7
     val isCentered = call.argument<Boolean>("isCentered") ?: true
+    var smoothTransition = call.argument<Boolean>("smoothTransition") ?: true
 
     val track = flutterWebRTCPlugin.getLocalTrack(trackId)
     if (track != null) {
@@ -75,7 +76,8 @@ class LiveKitPlugin: FlutterPlugin, MethodCallHandler {
     }
 
     val visualizer = Visualizer(
-      barCount = barCount, isCentered = isCentered,
+      barCount = barCount, isCentered = isCentered, 
+      smoothTransition = smoothTransition,
       audioTrack = audioTrack, binaryMessenger = binaryMessenger!!,
       visualizerId = visualizerId)
 

android/src/main/kotlin/io/livekit/plugin/Visualizer.kt

@@ -28,6 +28,7 @@ import kotlin.math.*
 class Visualizer(
     private var barCount: Int,
     private var isCentered: Boolean,
+    private var smoothTransition: Boolean,
     audioTrack: LKAudioTrack,
     binaryMessenger: BinaryMessenger,
     visualizerId: String
@@ -79,9 +80,13 @@ class Visualizer(
             amplitudes = centerBands(amplitudes)
         }
 
-        bands = bands.mapIndexed { index, value ->
-          smoothTransition(value, amplitudes[index], 0.3f)
-        }.toFloatArray()
+        if(this.smoothTransition) {
+            bands = bands.mapIndexed { index, value ->
+                smoothTransition(value, amplitudes[index], 0.3f)
+            }.toFloatArray()
+        } else {
+            bands = amplitudes
+        }
 
         handler.post {
             eventSink?.success(bands)

lib/src/support/native.dart

@@ -55,6 +55,7 @@ class Native {
     bool isCentered = true,
     int barCount = 7,
     String visualizerId = '',
+    bool smoothTransition = true,
   }) async {
     try {
       final result = await channel.invokeMethod<bool>(
@@ -64,6 +65,7 @@ class Native {
           'isCentered': isCentered,
           'barCount': barCount,
           'visualizerId': visualizerId,
+          'smoothTransition': smoothTransition,
         },
       );
       return result == true;

lib/src/track/audio_visualizer.dart

@@ -9,9 +9,11 @@ import 'audio_visualizer_native.dart'
 class AudioVisualizerOptions {
   final bool centeredBands;
   final int barCount;
+  final bool smoothTransition;
   const AudioVisualizerOptions({
     this.centeredBands = true,
     this.barCount = 7,
+    this.smoothTransition = true,
   });
 }
 

lib/src/track/audio_visualizer_native.dart

@@ -33,6 +33,7 @@ class AudioVisualizerNative extends AudioVisualizer {
       isCentered: visualizerOptions.centeredBands,
       barCount: visualizerOptions.barCount,
       visualizerId: visualizerId,
+      smoothTransition: visualizerOptions.smoothTransition,
     );
 
     _eventChannel = EventChannel(

lib/src/track/audio_visualizer_web.dart

@@ -34,7 +34,19 @@ class AudioVisualizerWeb extends AudioVisualizer {
 
     final bands = visualizerOptions.barCount;
 
-    _audioAnalyser = createAudioAnalyser(_audioTrack!, options.analyserOptions);
+    // Override smoothingTimeConstant to a very low valiue if smoothTransition is false
+    var currentAnalyserOptions =
+        options.analyserOptions ?? const AudioAnalyserOptions();
+    if (!visualizerOptions.smoothTransition) {
+      currentAnalyserOptions = AudioAnalyserOptions(
+        fftSize: currentAnalyserOptions.fftSize,
+        maxDecibels: currentAnalyserOptions.maxDecibels,
+        minDecibels: currentAnalyserOptions.minDecibels,
+        smoothingTimeConstant: 0.02,
+      );
+    }
+
+    _audioAnalyser = createAudioAnalyser(_audioTrack!, currentAnalyserOptions);
 
     final bufferLength = _audioAnalyser?.analyser.frequencyBinCount;
 

shared_swift/LiveKitPlugin.swift

@@ -113,6 +113,7 @@ public class LiveKitPlugin: NSObject, FlutterPlugin {
         let visualizerId = args["visualizerId"] as? String 
         let barCount = args["barCount"] as? Int ?? 7
         let isCentered = args["isCentered"] as? Bool ?? true
+        let smoothTransition = args["smoothTransition"] as? Bool ?? true
 
         if visualizerId == nil {
             result(FlutterError(code: "visualizerId", message: "visualizerId is required", details: nil))
@@ -129,6 +130,7 @@ public class LiveKitPlugin: NSObject, FlutterPlugin {
                                                binaryMessenger: self.binaryMessenger!,
                                                bandCount: barCount,
                                                isCentered: isCentered,
+                                               smoothTransition: smoothTransition,
                                                visualizerId: unwrappedVisualizerId)    
 
                 tracks[unwrappedTrackId] = lkLocalTrack
@@ -143,6 +145,7 @@ public class LiveKitPlugin: NSObject, FlutterPlugin {
                                                binaryMessenger: self.binaryMessenger!,
                                                bandCount: barCount,
                                                isCentered: isCentered,
+                                               smoothTransition: smoothTransition,
                                                visualizerId: unwrappedVisualizerId)
                 tracks[unwrappedTrackId] = lkRemoteTrack
                 processors[unwrappedVisualizerId] = processor

shared_swift/Visualizer.swift

@@ -43,7 +43,7 @@ public class Visualizer: NSObject, RTCAudioRenderer, FlutterStreamHandler {
 
     public let isCentered: Bool
     public let smoothingFactor: Float
-
+    public let smoothTransition: Bool
     public var bands: [Float]
 
     private let _processor: AudioVisualizeProcessor
@@ -53,11 +53,13 @@ public class Visualizer: NSObject, RTCAudioRenderer, FlutterStreamHandler {
                 binaryMessenger: FlutterBinaryMessenger,
                 bandCount: Int = 7,
                 isCentered: Bool = true,
+                smoothTransition: Bool = true,
                 smoothingFactor: Float = 0.3,
                 visualizerId: String)
     {
         self.isCentered = isCentered
         self.smoothingFactor = smoothingFactor
+        self.smoothTransition = smoothTransition
         bands = Array(repeating: 0.0, count: bandCount)
         _processor = AudioVisualizeProcessor(bandsCount: bandCount)
         _track = track
@@ -86,7 +88,10 @@ public class Visualizer: NSObject, RTCAudioRenderer, FlutterStreamHandler {
             guard let self else { return }
 
             self.bands = zip(self.bands, newBands).map { old, new in
-                self._smoothTransition(from: old, to: new, factor: self.smoothingFactor)
+                if(self.smoothTransition) {
+                    return self._smoothTransition(from: old, to: new, factor: self.smoothingFactor)
+                }
+                return new
             }
             self.eventSink?(self.bands)
         }