Make audio buffer configurable

karma.conf.js

@@ -47,7 +47,8 @@ module.exports = function (config) {
             clearContext: false,
             jasmine: {
                 random: false,
-                stopSpecOnExpectationFailure: false
+                stopSpecOnExpectationFailure: false.valueOf,
+                timeoutInterval: 30000
             }
         },
 

src.csharp/AlphaTab.Windows/NAudioSynthOutput.cs

@@ -14,7 +14,6 @@ public class NAudioSynthOutput : WaveProvider32, ISynthOutput, IDisposable
     {
         private const int BufferSize = 4096;
         private const int PreferredSampleRate = 44100;
-        private const int TotalBufferTimeInMilliseconds = 5000;
 
         private DirectSoundOut _context;
         private CircularSampleBuffer _circularBuffer;
@@ -41,10 +40,10 @@ public void Activate()
 
 
         /// <inheritdoc />
-        public void Open()
+        public void Open(double bufferTimeInMilliseconds)
         {
             _bufferCount = (int)(
-                (TotalBufferTimeInMilliseconds * PreferredSampleRate) /
+                (bufferTimeInMilliseconds * PreferredSampleRate) /
                 1000 /
                 BufferSize
             );

src.csharp/AlphaTab/Platform/CSharp/AlphaSynthWorkerApiBase.cs

@@ -10,13 +10,15 @@ internal abstract class AlphaSynthWorkerApiBase : IAlphaSynth
     {
         private readonly ISynthOutput _output;
         private LogLevel _logLevel;
+        private double _bufferTimeInMilliseconds;
 
         protected AlphaSynth Player;
 
-        protected AlphaSynthWorkerApiBase(ISynthOutput output, LogLevel logLevel)
+        protected AlphaSynthWorkerApiBase(ISynthOutput output, LogLevel logLevel, double bufferTimeInMilliseconds)
         {
             _output = output;
             _logLevel = logLevel;
+            _bufferTimeInMilliseconds = bufferTimeInMilliseconds;
             Player = null!;
         }
 
@@ -26,7 +28,7 @@ protected AlphaSynthWorkerApiBase(ISynthOutput output, LogLevel logLevel)
 
         protected void Initialize()
         {
-            Player = new AlphaSynth(_output);
+            Player = new AlphaSynth(_output, _bufferTimeInMilliseconds);
             Player.PositionChanged.On(OnPositionChanged);
             Player.StateChanged.On(OnStateChanged);
             Player.Finished.On(OnFinished);

src.csharp/AlphaTab/Platform/CSharp/ManagedThreadAlphaSynthWorkerApi.cs

@@ -13,8 +13,8 @@ internal class ManagedThreadAlphaSynthWorkerApi : AlphaSynthWorkerApiBase
         private CancellationTokenSource _workerCancellationToken;
         private readonly ManualResetEventSlim? _threadStartedEvent;
 
-        public ManagedThreadAlphaSynthWorkerApi(ISynthOutput output, LogLevel logLevel, Action<Action> uiInvoke)
-            : base(output, logLevel)
+        public ManagedThreadAlphaSynthWorkerApi(ISynthOutput output, LogLevel logLevel, Action<Action> uiInvoke, double bufferTimeInMilliseconds)
+            : base(output, logLevel, bufferTimeInMilliseconds)
         {
             _uiInvoke = uiInvoke;
 

src.csharp/AlphaTab/Platform/CSharp/ManagedUiFacade.cs

@@ -44,7 +44,7 @@ public IScoreRenderer CreateWorkerRenderer()
         public IAlphaSynth CreateWorkerPlayer()
         {
             var player = new ManagedThreadAlphaSynthWorkerApi(CreateSynthOutput(),
-                Api.Settings.Core.LogLevel, BeginInvoke);
+                Api.Settings.Core.LogLevel, BeginInvoke, Api.Settings.Player.BufferTimeInMilliseconds);
             player.Ready.On(() =>
             {
                 using (var sf = OpenDefaultSoundFont())

src.kotlin/alphaTab/alphaTab/src/androidMain/kotlin/alphaTab/platform/android/AndroidSynthOutput.kt

@@ -16,7 +16,6 @@ internal class AndroidSynthOutput(
     companion object {
         private const val BufferSize = 4096
         private const val PreferredSampleRate = 44100
-        private const val TotalBufferTimeInMilliseconds = 5000
     }
 
     private var _bufferCount = 0
@@ -31,10 +30,10 @@ internal class AndroidSynthOutput(
     override fun activate() {
     }
 
-    override fun open() {
-        _bufferCount = (TotalBufferTimeInMilliseconds * PreferredSampleRate /
+    override fun open(bufferTimeInMilliseconds: Double) {
+        _bufferCount = (bufferTimeInMilliseconds * PreferredSampleRate /
             1000 /
-            BufferSize)
+            BufferSize).toInt()
         _circularBuffer = CircularSampleBuffer((BufferSize * _bufferCount).toDouble())
 
         _audioContext = AndroidAudioWorker(

src.kotlin/alphaTab/alphaTab/src/androidMain/kotlin/alphaTab/platform/android/AndroidThreadAlphaSynthWorkerPlayer.kt

@@ -28,13 +28,16 @@ internal class AndroidThreadAlphaSynthWorkerPlayer : IAlphaSynth, Runnable {
     private var _player: AlphaSynth? = null
     private val _output: ISynthOutput
     private var _logLevel: LogLevel
+    private var _bufferTimeInMilliseconds: Double
 
     constructor(
         logLevel: LogLevel,
         output: ISynthOutput,
-        uiInvoke: (action: (() -> Unit)) -> Unit
+        uiInvoke: (action: (() -> Unit)) -> Unit,
+        bufferTimeInMilliseconds: Double
     ) {
         _logLevel = logLevel
+        _bufferTimeInMilliseconds = bufferTimeInMilliseconds
         _output = output
         _uiInvoke = uiInvoke
         _threadStartedEvent = Semaphore(1)
@@ -78,7 +81,7 @@ internal class AndroidThreadAlphaSynthWorkerPlayer : IAlphaSynth, Runnable {
     }
 
     private fun initialize() {
-        val player = AlphaSynth(_output)
+        val player = AlphaSynth(_output, _bufferTimeInMilliseconds)
         _player = player
         player.positionChanged.on {
             _uiInvoke { onPositionChanged(it) }

src.kotlin/alphaTab/alphaTab/src/androidMain/kotlin/alphaTab/platform/android/AndroidUiFacade.kt

@@ -158,7 +158,8 @@ internal class AndroidUiFacade : IUiFacade<AlphaTabView> {
             AndroidSynthOutput {
                 player!!.addToWorker(it)
             },
-            this::beginInvoke
+            this::beginInvoke,
+            api.settings.player.bufferTimeInMilliseconds
         )
         player.ready.on {
             val soundFont = openDefaultSoundFont()

src/PlayerSettings.ts

@@ -186,4 +186,11 @@ export class PlayerSettings {
      * Gets or sets whether the triplet feel should be applied/played during audio playback.
      */
     public playTripletFeel: boolean = true;
+
+    /**
+     * Gets or sets how many milliseconds of audio samples should be buffered in total. 
+     * Larger buffers cause a delay from when audio settings like volumes will be applied. 
+     * Smaller buffers can cause audio crackling due to constant buffering that is happening.
+     */
+    public bufferTimeInMilliseconds:number = 500;
 }

src/generated/PlayerSettingsSerializer.ts

@@ -37,6 +37,7 @@ export class PlayerSettingsSerializer {
         o.set("vibrato", VibratoPlaybackSettingsSerializer.toJson(obj.vibrato)); 
         o.set("slide", SlidePlaybackSettingsSerializer.toJson(obj.slide)); 
         o.set("playtripletfeel", obj.playTripletFeel); 
+        o.set("buffertimeinmilliseconds", obj.bufferTimeInMilliseconds); 
         return o; 
     }
     public static setProperty(obj: PlayerSettings, property: string, v: unknown): boolean {
@@ -88,6 +89,9 @@ export class PlayerSettingsSerializer {
             case "playtripletfeel":
                 obj.playTripletFeel = v! as boolean;
                 return true;
+            case "buffertimeinmilliseconds":
+                obj.bufferTimeInMilliseconds = v! as number;
+                return true;
         } 
         if (["vibrato"].indexOf(property) >= 0) {
             VibratoPlaybackSettingsSerializer.fromJson(obj.vibrato, v as Map<string, unknown>);

src/platform/javascript/AlphaSynthAudioWorkletOutput.ts

@@ -41,29 +41,27 @@ declare var sampleRate: number;
 export class AlphaSynthWebWorklet {
     private static _isRegistered = false;
     public static init() {
-        if(AlphaSynthWebWorklet._isRegistered) {
+        if (AlphaSynthWebWorklet._isRegistered) {
             return;
         }
-        AlphaSynthWebWorklet._isRegistered = true; 
+        AlphaSynthWebWorklet._isRegistered = true;
         registerProcessor(
             'alphatab',
             class AlphaSynthWebWorkletProcessor extends AudioWorkletProcessor {
                 public static readonly BufferSize: number = 4096;
-                private static readonly TotalBufferTimeInMilliseconds: number = 5000;
 
                 private _outputBuffer: Float32Array = new Float32Array(0);
                 private _circularBuffer!: CircularSampleBuffer;
                 private _bufferCount: number = 0;
                 private _requestedBufferCount: number = 0;
 
-                constructor(...args: any[]) {
-                    super(...args);
+                constructor(options: AudioWorkletNodeOptions) {
+                    super(options);
 
                     Logger.debug('WebAudio', 'creating processor');
 
                     this._bufferCount = Math.floor(
-                        (AlphaSynthWebWorkletProcessor.TotalBufferTimeInMilliseconds *
-                            sampleRate) /
+                        (options.processorOptions.bufferTimeInMilliseconds * sampleRate) /
                             1000 /
                             AlphaSynthWebWorkletProcessor.BufferSize
                     );
@@ -111,7 +109,11 @@ export class AlphaSynthWebWorklet {
                         buffer = new Float32Array(samples);
                         this._outputBuffer = buffer;
                     }
-                    const samplesFromBuffer = this._circularBuffer.read(buffer, 0, Math.min(buffer.length, this._circularBuffer.count));
+                    const samplesFromBuffer = this._circularBuffer.read(
+                        buffer,
+                        0,
+                        Math.min(buffer.length, this._circularBuffer.count)
+                    );
                     let s: number = 0;
                     for (let i: number = 0; i < left.length; i++) {
                         left[i] = buffer[s++];
@@ -158,9 +160,11 @@ export class AlphaSynthWebWorklet {
  */
 export class AlphaSynthAudioWorkletOutput extends AlphaSynthWebAudioOutputBase {
     private _worklet: AudioWorkletNode | null = null;
+    private _bufferTimeInMilliseconds: number = 0;
 
-    public override open() {
-        super.open();
+    public override open(bufferTimeInMilliseconds: number) {
+        super.open(bufferTimeInMilliseconds);
+        this._bufferTimeInMilliseconds = bufferTimeInMilliseconds;
         this.onReady();
     }
 
@@ -172,10 +176,12 @@ export class AlphaSynthAudioWorkletOutput extends AlphaSynthWebAudioOutputBase {
             () => {
                 this._worklet = new AudioWorkletNode(ctx!, 'alphatab', {
                     numberOfOutputs: 1,
-                    outputChannelCount: [2]
+                    outputChannelCount: [2],
+                    processorOptions: {
+                        bufferTimeInMilliseconds: this._bufferTimeInMilliseconds
+                    }
                 });
                 this._worklet.port.onmessage = this.handleMessage.bind(this);
-
                 this._source!.connect(this._worklet);
                 this._source!.start(0);
                 this._worklet.connect(ctx!.destination);

src/platform/javascript/AlphaSynthScriptProcessorOutput.ts

@@ -15,12 +15,10 @@ export class AlphaSynthScriptProcessorOutput extends AlphaSynthWebAudioOutputBas
     private _bufferCount: number = 0;
     private _requestedBufferCount: number = 0;
 
-    public override open() {
-        super.open();
+    public override open(bufferTimeInMilliseconds: number) {
+        super.open(bufferTimeInMilliseconds);
         this._bufferCount = Math.floor(
-            (AlphaSynthWebAudioOutputBase.TotalBufferTimeInMilliseconds * this.sampleRate) /
-                1000 /
-                AlphaSynthWebAudioOutputBase.BufferSize
+            (bufferTimeInMilliseconds * this.sampleRate) / 1000 / AlphaSynthWebAudioOutputBase.BufferSize
         );
         this._circularBuffer = new CircularSampleBuffer(AlphaSynthWebAudioOutputBase.BufferSize * this._bufferCount);
         this.onReady();
@@ -87,7 +85,11 @@ export class AlphaSynthScriptProcessorOutput extends AlphaSynthWebAudioOutputBas
             buffer = new Float32Array(samples);
             this._outputBuffer = buffer;
         }
-        const samplesFromBuffer = this._circularBuffer.read(buffer, 0, Math.min(buffer.length, this._circularBuffer.count));
+        const samplesFromBuffer = this._circularBuffer.read(
+            buffer,
+            0,
+            Math.min(buffer.length, this._circularBuffer.count)
+        );
         let s: number = 0;
         for (let i: number = 0; i < left.length; i++) {
             left[i] = buffer[s++];

src/platform/javascript/AlphaSynthWebAudioOutputBase.ts

@@ -12,7 +12,6 @@ declare var webkitAudioContext: any;
 export abstract class AlphaSynthWebAudioOutputBase implements ISynthOutput {
     protected static readonly BufferSize: number = 4096;
     protected static readonly PreferredSampleRate: number = 44100;
-    protected static readonly TotalBufferTimeInMilliseconds: number = 5000;
 
     protected _context: AudioContext | null = null;
     protected _buffer: AudioBuffer | null = null;
@@ -75,15 +74,15 @@ export abstract class AlphaSynthWebAudioOutputBase implements ISynthOutput {
         throw new AlphaTabError(AlphaTabErrorType.General, 'AudioContext not found');
     }
 
-    public open(): void {
+    public open(bufferTimeInMilliseconds: number): void {
         this.patchIosSampleRate();
         this._context = this.createAudioContext();
         let ctx: any = this._context;
         if (ctx.state === 'suspended') {
             this.registerResumeHandler();
         }
     }
-    
+
     private registerResumeHandler() {
         this._resumeHandler = (() => {
             this.activate(() => {
@@ -93,7 +92,7 @@ export abstract class AlphaSynthWebAudioOutputBase implements ISynthOutput {
         document.body.addEventListener('touchend', this._resumeHandler, false);
         document.body.addEventListener('click', this._resumeHandler, false);
     }
-    
+
     private unregisterResumeHandler() {
         const resumeHandler = this._resumeHandler;
         if (resumeHandler) {

src/platform/javascript/AlphaSynthWebWorker.ts

@@ -18,11 +18,11 @@ export class AlphaSynthWebWorker {
     private _player: AlphaSynth;
     private _main: IWorkerScope;
 
-    public constructor(main: IWorkerScope) {
+    public constructor(main: IWorkerScope, bufferTimeInMilliseconds:number) {
         this._main = main;
         this._main.addEventListener('message', this.handleMessage.bind(this));
 
-        this._player = new AlphaSynth(new AlphaSynthWorkerSynthOutput());
+        this._player = new AlphaSynth(new AlphaSynthWorkerSynthOutput(), bufferTimeInMilliseconds);
         this._player.positionChanged.on(this.onPositionChanged.bind(this));
         this._player.stateChanged.on(this.onPlayerStateChanged.bind(this));
         this._player.finished.on(this.onFinished.bind(this));
@@ -48,7 +48,7 @@ export class AlphaSynthWebWorker {
                 case 'alphaSynth.initialize':
                     AlphaSynthWorkerSynthOutput.preferredSampleRate = data.sampleRate;
                     Logger.logLevel = data.logLevel;
-                    Environment.globalThis.alphaSynthWebWorker = new AlphaSynthWebWorker(main);
+                    Environment.globalThis.alphaSynthWebWorker = new AlphaSynthWebWorker(main, data.bufferTimeInMilliseconds);
                     break;
             }
         });