✨ Update recorder normalization and updated default values for sample rate and bit rate. (#99)

Co-authored-by: ujas-m-simformsolutions <[email protected]>

Author: Ujas-Majithiya

CHANGELOG.md

@@ -1,7 +1,7 @@
-## 1.0.0 (Unreleased)
+## 1.0.0
 
 - Reworked waveforms from audio file
-  - Breaking: removed `readingComplete` PlayerState and `visualizerHeight`. With this, added `extractWaveforms` function to extract waveforms.
+  - **Breaking**: removed `readingComplete` PlayerState and `visualizerHeight`. With this, added `extractWaveforms` function to extract waveforms.
   - Added `WaveformType` enum for selecting longer or shorter type of waveform.
   - Added `onCurrentExtractedWaveformData` and `onExtractionProgress` to monitor progress and currently extracted waveform data.
   - improved drawing of waveforms.
@@ -10,7 +10,10 @@
 - Fixed [#101](https://github.com/SimformSolutionsPvtLtd/audio_waveforms/issues/101) - Fixed setting volume for android throws error
 - Fixed zero duration would cause waveforms not to expand
 - Fixed `postFrameCallback` error for flutter version below 3.0.0
+- **BREAKING**: Replaced `normalizationFactor` with `scaleFactor`and with this fixed [#43](https://github.com/SimformSolutionsPvtLtd/audio_waveforms/issues/43) 
 - Updated default values for bitRate and sampleRate
+- Encoders, sample rate and bit rate can now Directly be set from `record` function.
+- Updated example app
 
 ## 0.1.5+1
 

android/src/main/kotlin/com/simform/audio_waveforms/AudioRecorder.kt

@@ -12,20 +12,14 @@ import io.flutter.plugin.common.MethodChannel
 import io.flutter.plugin.common.PluginRegistry
 import java.io.IOException
 import java.lang.IllegalStateException
-import kotlin.math.log10
 
 private const val LOG_TAG = "AudioWaveforms"
 private const val RECORD_AUDIO_REQUEST_CODE = 1001
 
 class AudioRecorder : PluginRegistry.RequestPermissionsResultListener {
     private var permissions = arrayOf(Manifest.permission.RECORD_AUDIO)
     fun getDecibel(result: MethodChannel.Result, recorder: MediaRecorder?) {
-        val db = 20 * log10((recorder?.maxAmplitude?.toDouble() ?: 0.0 / 32768.0))
-        if (db == Double.NEGATIVE_INFINITY) {
-            Log.d(LOG_TAG, "Microphone might be turned off")
-        } else {
-            result.success(db)
-        }
+        result.success(recorder?.maxAmplitude?.toDouble() ?: 0.0)
     }
 
     @RequiresApi(Build.VERSION_CODES.LOLLIPOP)

example/lib/main.dart

@@ -222,7 +222,7 @@ class _HomeState extends State<Home> with WidgetsBindingObserver {
         debugPrint(path);
       }
     } else {
-      await recorderController.record(path);
+      await recorderController.record(path: path);
     }
     setState(() {
       isRecording = !isRecording;

ios/Classes/AudioRecorder.swift

@@ -9,9 +9,9 @@ public class AudioRecorder: NSObject, AVAudioRecorderDelegate{
 
     public func startRecording(_ result: @escaping FlutterResult,_ path: String?,_ encoder : Int?,_ sampleRate : Int?,_ bitRate : Int?,_ fileNameFormat: String){
         let settings = [
-            AVEncoderBitRateKey: bitRate ?? 64000,
+            AVEncoderBitRateKey: bitRate ?? 48000,
             AVFormatIDKey: getEncoder(encoder ?? 0),
-            AVSampleRateKey: sampleRate ?? 16000,
+            AVSampleRateKey: sampleRate ?? 44100,
             AVNumberOfChannelsKey: 1,
             AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue
         ]
@@ -62,8 +62,9 @@ public class AudioRecorder: NSObject, AVAudioRecorderDelegate{
 
     public func getDecibel(_ result: @escaping FlutterResult) {
         audioRecorder?.updateMeters()
-        let amp = audioRecorder?.averagePower(forChannel: 0) ?? 0.0
-        result(amp)
+        let amp = audioRecorder?.peakPower(forChannel: 0) ?? 0.0
+        let linear = pow(10, amp / 20);
+        result(linear)
     }
 
     public func checkHasPermission(_ result: @escaping FlutterResult){

lib/src/audio_waveforms.dart

@@ -113,6 +113,7 @@ class _AudioWaveformsState extends State<AudioWaveforms> {
                     widget.recorderController.setScrolledPositionDuration,
                 shouldCalculateScrolledPosition:
                     widget.shouldCalculateScrolledPosition,
+                scaleFactor: widget.waveStyle.scaleFactor,
               ),
             ),
           ),

lib/src/base/utils.dart

@@ -176,3 +176,13 @@ extension PlayerStateExtension on PlayerState {
 
   bool get isPaused => this == PlayerState.paused;
 }
+
+extension RecorderStateExtension on RecorderState {
+  bool get isRecording => this == RecorderState.recording;
+
+  bool get isInitialized => this == RecorderState.initialized;
+
+  bool get isPaused => this == RecorderState.paused;
+
+  bool get isStopped => this == RecorderState.stopped;
+}

lib/src/base/wave_style.dart

@@ -82,8 +82,8 @@ class WaveStyle {
   /// ```dart
   final Shader? gradient;
 
-  /// This is applied to each wave while generating.
-  /// Use this to [scale] the waves. Defaults to 1.0.
+  /// Default normalised amplitude/power we have are between 0.0 and 1.0.
+  /// So scale them, [scaleFactor] can be used. Defaults to 20.0.
   final double scaleFactor;
 
   /// A model class to provide style to the waveforms.
@@ -112,7 +112,7 @@ class WaveStyle {
     this.durationTextPadding = 20.0,
     this.durationLinesColor = Colors.blueAccent,
     this.gradient,
-    this.scaleFactor = 1.0,
+    this.scaleFactor = 20.0,
   }) : assert(waveThickness < spacing,
             "waveThickness can't be greater than spacing");
 }

lib/src/controllers/recorder_controller.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:io' show Platform;
+import 'dart:math' show max;
 
 import 'package:flutter/material.dart';
 
@@ -10,23 +11,26 @@ class RecorderController extends ChangeNotifier {
   final List<double> _waveData = [];
 
   /// At which rate waveform needs to be updated
-  late Duration updateFrequency = const Duration(milliseconds: 100);
+  Duration updateFrequency = const Duration(milliseconds: 100);
 
-  late AndroidEncoder androidEncoder = AndroidEncoder.aac;
+  AndroidEncoder androidEncoder = AndroidEncoder.aac;
 
-  late AndroidOutputFormat androidOutputFormat = AndroidOutputFormat.mpeg4;
+  AndroidOutputFormat androidOutputFormat = AndroidOutputFormat.mpeg4;
 
-  late IosEncoder iosEncoder = IosEncoder.kAudioFormatMPEG4AAC;
+  IosEncoder iosEncoder = IosEncoder.kAudioFormatMPEG4AAC;
 
-  late int sampleRate = 44100;
+  int sampleRate = 44100;
 
-  late int bitRate = 48000;
+  int bitRate = 48000;
 
-  ///Db we get from native is too high so in Android it the value is subtracted
-  ///and in IOS value added
-  late double normalizationFactor = Platform.isAndroid ? 60 : 40;
+  /// Current maximum peak power for ios and peak amplitude android.
+  double _maxPeak = Platform.isIOS ? 1 : 32786.0;
 
-  ///Current list of decibels(different values for each platform)
+  /// Current list of scaled waves. For IOS, this list contains normalised
+  /// peak power and for Android, this list contains normalised peak
+  /// amplitude.
+  ///
+  /// Values are between 0.0 to 1.0.
   List<double> get waveData => _waveData;
 
   RecorderState _recorderState = RecorderState.stopped;
@@ -92,14 +96,27 @@ class RecorderController extends ChangeNotifier {
   ///
   /// 2. Stopped -: If a recorder is stopped from previous recording and again
   /// this function is called then it will re-initialise the recorder.
-  Future<void> record([String? path]) async {
-    if (_recorderState != RecorderState.recording) {
+  Future<void> record({
+    String? path,
+    AndroidEncoder? androidEncoder,
+    AndroidOutputFormat? androidOutputFormat,
+    IosEncoder? iosEncoder,
+    int? sampleRate,
+    int? bitRate,
+  }) async {
+    if (!_recorderState.isRecording) {
       await checkPermission();
       if (_hasPermission) {
-        if (Platform.isAndroid && _recorderState == RecorderState.stopped) {
-          await _initRecorder(path);
+        if (Platform.isAndroid && _recorderState.isStopped) {
+          await _initRecorder(
+            path: path,
+            androidEncoder: androidEncoder,
+            androidOutputFormat: androidOutputFormat,
+            sampleRate: sampleRate,
+            bitRate: bitRate,
+          );
         }
-        if (_recorderState == RecorderState.paused) {
+        if (_recorderState.isPaused) {
           _isRecording = await AudioWaveformsInterface.instance.resume();
           if (_isRecording) {
             _startTimer();
@@ -113,12 +130,13 @@ class RecorderController extends ChangeNotifier {
         if (Platform.isIOS) {
           _recorderState = RecorderState.initialized;
         }
-        if (_recorderState == RecorderState.initialized) {
+        if (_recorderState.isInitialized) {
           _isRecording = await AudioWaveformsInterface.instance.record(
-            audioFormat:
-                Platform.isIOS ? iosEncoder.index : androidEncoder.index,
-            sampleRate: sampleRate,
-            bitRate: bitRate,
+            audioFormat: Platform.isIOS
+                ? iosEncoder?.index ?? this.iosEncoder.index
+                : androidEncoder?.index ?? this.androidEncoder.index,
+            sampleRate: sampleRate ?? this.sampleRate,
+            bitRate: bitRate ?? this.bitRate,
             path: path,
           );
           if (_isRecording) {
@@ -137,13 +155,20 @@ class RecorderController extends ChangeNotifier {
   }
 
   /// Initialises recorder for android platform.
-  Future<void> _initRecorder(String? path) async {
+  Future<void> _initRecorder({
+    String? path,
+    AndroidEncoder? androidEncoder,
+    AndroidOutputFormat? androidOutputFormat,
+    int? sampleRate,
+    int? bitRate,
+  }) async {
     final initialized = await AudioWaveformsInterface.instance.initRecorder(
       path: path,
-      encoder: androidEncoder.index,
-      outputFormat: androidOutputFormat.index,
-      sampleRate: sampleRate,
-      bitRate: bitRate,
+      encoder: androidEncoder?.index ?? this.androidEncoder.index,
+      outputFormat:
+          androidOutputFormat?.index ?? this.androidOutputFormat.index,
+      sampleRate: sampleRate ?? this.sampleRate,
+      bitRate: bitRate ?? this.bitRate,
     );
     if (initialized) {
       _recorderState = RecorderState.initialized;
@@ -172,7 +197,7 @@ class RecorderController extends ChangeNotifier {
 
   /// Pauses the current recording. Call [record] to resume recording.
   Future<void> pause() async {
-    if (_recorderState == RecorderState.recording) {
+    if (_recorderState.isRecording) {
       _isRecording = (await AudioWaveformsInterface.instance.pause()) ?? true;
       if (_isRecording) {
         throw "Failed to pause recording";
@@ -195,8 +220,7 @@ class RecorderController extends ChangeNotifier {
   /// manually else it will start showing waveforms from same place where it
   /// left of for previous recording.
   Future<String?> stop([bool callReset = true]) async {
-    if (_recorderState == RecorderState.recording ||
-        _recorderState == RecorderState.paused) {
+    if (_recorderState.isRecording || _recorderState.isPaused) {
       final path = await AudioWaveformsInterface.instance.stop();
 
       if (path != null) {
@@ -251,19 +275,12 @@ class RecorderController extends ChangeNotifier {
     );
   }
 
-  /// Normalises the decibel
-  void _normalise(double db) {
-    if (Platform.isAndroid) {
-      waveData.add(db - normalizationFactor);
-    } else {
-      if (db == 0.0) {
-        waveData.add(0);
-      } else if (db + normalizationFactor < 1) {
-        waveData.add(0);
-      } else {
-        waveData.add(db + normalizationFactor);
-      }
-    }
+  /// Normalises the peak power for ios and peak amplitude for android
+  void _normalise(double peak) {
+    final absDb = peak.abs();
+    _maxPeak = max(absDb, _maxPeak);
+    final scaledWave = (absDb / _maxPeak);
+    _waveData.add(scaledWave);
     notifyListeners();
   }
 

lib/src/painters/recorder_wave_painter.dart

@@ -48,6 +48,7 @@ class RecorderWavePainter extends CustomPainter {
   final VoidCallback revertClearlabelCall;
   final Function(int) setCurrentPositionDuration;
   final bool shouldCalculateScrolledPosition;
+  final double scaleFactor;
 
   RecorderWavePainter({
     required this.waveData,
@@ -80,6 +81,7 @@ class RecorderWavePainter extends CustomPainter {
     required this.revertClearlabelCall,
     required this.setCurrentPositionDuration,
     required this.shouldCalculateScrolledPosition,
+    required this.scaleFactor,
   })  : _wavePaint = Paint()
           ..color = waveColor
           ..strokeWidth = waveThickness
@@ -201,7 +203,7 @@ class RecorderWavePainter extends CustomPainter {
                 dragOffset.dx +
                 (spacing * i) -
                 initialPosition,
-            -waveData[i] + size.height - bottomPadding),
+            -(waveData[i] * scaleFactor) + size.height - bottomPadding),
         _wavePaint);
   }
 
@@ -218,7 +220,7 @@ class RecorderWavePainter extends CustomPainter {
                 dragOffset.dx +
                 (spacing * i) -
                 initialPosition,
-            waveData[i] + size.height - bottomPadding),
+            (waveData[i] * scaleFactor) + size.height - bottomPadding),
         _wavePaint);
   }
 

pubspec.yaml

@@ -1,6 +1,6 @@
 name: audio_waveforms
 description: A Flutter package that allow you to generate waveform while recording audio or from audio file.
-version: 0.1.6
+version: 1.0.0
 homepage: https://github.com/SimformSolutionsPvtLtd/audio_waveforms
 issue_tracker: https://github.com/SimformSolutionsPvtLtd/audio_waveforms/issues