update NukedOPL3Sharp, add direct dependencies to Iir, MVerb and Speex

LICENSE

@@ -202,8 +202,15 @@
    limitations under the License.
 
 
-   Third-party libraries are licensed as followed:
-   - Adlib Gold: Personal permission granted by John Novak from DosBox Staging
-   - Nuked-OPL3: LGPL-2.1
-   - iir1: MIT
-   - YM7128B_emu: BSD 2-Clause
+   Third-party audio components retain their respective licenses:
+   - AdLib Gold: personal porting permission granted by John Novak from
+     DOSBox Staging.
+   - NukedOPL3Sharp: LGPL-2.1-only; upstream Nuked OPL3 source is
+     LGPL-2.1-or-later.
+   - Iir1.Net and upstream iir1: MIT.
+   - MVerb.Net and upstream MVerb: GPL-3.0-or-later.
+   - SpeexResamplerSharp and upstream SpeexDSP: BSD-3-Clause.
+   - YM7128B_emu: BSD-2-Clause.
+
+   See NOTICE for copyright attribution and the corresponding dependency
+   packages and source directories for their license texts.

NOTICE

@@ -17,11 +17,33 @@ Authors:
 - Stefan Hueg
 - Thomas Kaiser
 
-Third party authors:
+Third-party audio components:
 - Greg Divis (Aeon project: https://github.com/gregdivis/Aeon)
+- AdLib Gold audio code is ported from DOSBox Staging with personal permission
+  from project lead and original component author John Novak.
+- NukedOPL3Sharp is Stefan Hueg's C# port of Nuked OPL3 by Nuke.YKT,
+  copyright (c) 2013-2020 Nuke.YKT, licensed under LGPL-2.1-only.
+- YM7128B is ported from Andrea Zoppi's YM7128B_emu,
+  copyright (c) 2020-2023 Andrea Zoppi, licensed under BSD-2-Clause.
+- Iir1.Net is copyright (c) 2026 Stefan Hueg and is a managed derivative of
+  iir1, copyright (c) 2009 Vinnie Falco and copyright (c) 2012 Bernd Porr.
+  Both are licensed under MIT.
+- MVerb.Net is a managed derivative of MVerb, copyright (c) 2010 Martin
+  Eastwood, with the managed port copyright (c) 2026 Stefan Hueg. It is
+  licensed under GPL-3.0-or-later.
+- SpeexResamplerSharp is copyright (c) 2026 Stefan Hueg and the SpeexDSP
+  contributors. It is a managed port of the SpeexDSP resampler by Jean-Marc
+  Valin, Thorvald Natvig, and the Xiph.Org contributors, licensed under
+  BSD-3-Clause.
 
+The NuGet packages declare their applicable licenses. Iir1.Net, MVerb.Net,
+and SpeexResamplerSharp also include their upstream third-party notices. The
+YM7128B license is preserved beside its source under
+src/Spice86.Core/Emulator/Devices/Sound/YM7128B/LICENSE.
 
-Licensed under the Apache License, Version 2.0 (the "License");
+
+Spice86 project-authored code is licensed under the Apache License, Version
+2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 

src/Directory.Packages.props

@@ -14,6 +14,8 @@
     <PackageVersion Include="BenchmarkDotNet" Version="0.15.8" />
     <PackageVersion Include="bodong.Avalonia.PropertyGrid" Version="12.0.4.1" />
     <PackageVersion Include="bodong.PropertyModels" Version="12.0.0" />
+    <PackageVersion Include="Iir1.Net" Version="1.0.0" />
+    <PackageVersion Include="MVerb.Net" Version="1.0.0" />
     <PackageVersion Include="Spectre.Console.Cli" Version="0.55.0" />
     <PackageVersion Include="CommunityToolkit.HighPerformance" Version="8.4.2" />
     <PackageVersion Include="CommunityToolkit.Mvvm" Version="8.4.2" />
@@ -38,12 +40,13 @@
     <PackageVersion Include="Mt32emu.net" Version="1.0.0" />
     <PackageVersion Include="NSubstitute" Version="6.0.0" />
     <PackageVersion Include="NSubstitute.Analyzers.CSharp" Version="1.0.17" />
-    <PackageVersion Include="NukedOPL3Sharp" Version="1.2.1" />
+    <PackageVersion Include="NukedOPL3Sharp" Version="1.3.1" />
     <PackageVersion Include="PanAndZoom" Version="12.0.0.1" />
     <PackageVersion Include="Roslynator.Analyzers" Version="4.15.0" />
     <PackageVersion Include="Roslynator.CodeAnalysis.Analyzers" Version="4.15.0" />
     <PackageVersion Include="Semi.Avalonia" Version="12.1.0.1" />
     <PackageVersion Include="Semi.Avalonia.Dock" Version="12.0.0.2" />
+    <PackageVersion Include="SpeexResamplerSharp" Version="1.0.0" />
     <PackageVersion Include="Spice86.DataGrid" Version="0.1.2" />
     <PackageVersion Include="Serilog" Version="4.4.0" />
     <PackageVersion Include="Serilog.Extensions.Hosting" Version="10.0.0" />

src/Spice86.Core/Emulator/Devices/Sound/AdlibGoldOpl/StereoProcessor.cs

@@ -1,7 +1,8 @@
 namespace Spice86.Core.Emulator.Devices.Sound.AdlibGoldOpl;
 
+using Iir.RBJ;
+
 using Spice86.Audio.Common;
-using Spice86.Audio.Filters.IirFilters.Filters.RBJ;
 
 /// <summary>
 ///     Implements the AdLib Gold stereo processor, including tone controls and stereo field shaping.

src/Spice86.Core/Emulator/Devices/Sound/SoftwareMixer.cs

@@ -1,5 +1,9 @@
 namespace Spice86.Core.Emulator.Devices.Sound;
 
+using Iir.Butterworth;
+
+using MVerb;
+
 using Spice86.Audio.Backend.Audio;
 using Spice86.Audio.Common;
 using Spice86.Audio.Filters;
@@ -9,8 +13,6 @@
 using System.Runtime.InteropServices;
 using System.Threading;
 
-using HighPassFilter = Spice86.Audio.Filters.IirFilters.Filters.Butterworth.HighPass;
-
 /// <summary>
 /// Central audio mixer that runs in its own thread and produces final mixed output.
 /// </summary>
@@ -65,12 +67,12 @@
 
     // Reverb state - MVerb professional algorithmic reverb
     private readonly bool _doReverb = false;
     private readonly MVerb _mverb = new();
     private readonly float _reverbSynthSendLevel = 0.0f;
     private readonly float _reverbDigitalSendLevel = 0.0f;
 
-    private float _reverbLeftIn;
-    private float _reverbRightIn;
+    private readonly float[] _reverbLeft = new float[DefaultBlocksize];
+    private readonly float[] _reverbRight = new float[DefaultBlocksize];
 
     private readonly bool _doChorus = false;
     private readonly ChorusEngine _chorusEngine;
@@ -82,8 +84,8 @@
     private readonly float _crossfeedGlobalStrength = 0.0f; // Varies by preset: Light=0.20f, Normal=0.40f, Strong=0.60f
 
     // Used on reverb input and master output
-    private readonly HighPassFilter[] _reverbHighPassFilter;
-    private readonly HighPassFilter[] _masterHighPassFilter;
+    private readonly HighPass[] _reverbHighPassFilter;
+    private readonly HighPass[] _masterHighPassFilter;
     private const int HighPassFilterOrder = 2; // 2nd-order Butterworth
     private const float MasterHighPassCutoffHz = 20.0f;
 
@@ -105,15 +107,15 @@
         }
 
         // Initialize high-pass filters (2 channels - left and right)
-        _reverbHighPassFilter = new HighPassFilter[2];
-        _masterHighPassFilter = new HighPassFilter[2];
+        _reverbHighPassFilter = new HighPass[2];
+        _masterHighPassFilter = new HighPass[2];
         const float DefaultReverbHighPassHz = 200.0f;
 
         for (int i = 0; i < 2; i++) {
-            _reverbHighPassFilter[i] = new HighPassFilter(HighPassFilterOrder);
+            _reverbHighPassFilter[i] = new HighPass(HighPassFilterOrder);
             _reverbHighPassFilter[i].Setup(HighPassFilterOrder, _sampleRateHz, DefaultReverbHighPassHz);
 
-            _masterHighPassFilter[i] = new HighPassFilter(HighPassFilterOrder);
+            _masterHighPassFilter[i] = new HighPass(HighPassFilterOrder);
             _masterHighPassFilter[i].Setup(HighPassFilterOrder, _sampleRateHz, MasterHighPassCutoffHz);
         }
 
@@ -516,19 +518,21 @@
         // results to the master output.
         Span<AudioFrame> reverbAux = _reverbAuxBuffer.AsSpan();
         Span<AudioFrame> output = _outputBuffer.AsSpan();
+        int frameCount = reverbAux.Length;
+        Span<float> reverbLeft = _reverbLeft.AsSpan(0, frameCount);
+        Span<float> reverbRight = _reverbRight.AsSpan(0, frameCount);
 
-        for (int i = 0; i < reverbAux.Length; i++) {
+        for (int i = 0; i < frameCount; i++) {
             // High-pass filter the reverb input
             AudioFrame inFrame = reverbAux[i];
-            inFrame = new AudioFrame(
-                _reverbHighPassFilter[0].Filter(inFrame.Left),
-                _reverbHighPassFilter[1].Filter(inFrame.Right)
-            );
-            // MVerb operates on two non-interleaved sample streams
-            _reverbLeftIn = inFrame.Left;
-            _reverbRightIn = inFrame.Right;
-            _mverb.Process(ref _reverbLeftIn, ref _reverbRightIn);
-            output[i] += new AudioFrame(_reverbLeftIn, _reverbRightIn);
+            reverbLeft[i] = _reverbHighPassFilter[0].Filter(inFrame.Left);
+            reverbRight[i] = _reverbHighPassFilter[1].Filter(inFrame.Right);
+        }
+
+        _mverb.Process(reverbLeft, reverbRight, reverbLeft, reverbRight, frameCount);
+
+        for (int i = 0; i < frameCount; i++) {
+            output[i] += new AudioFrame(reverbLeft[i], reverbRight[i]);
         }
     }
 
@@ -608,4 +612,4 @@
             device.Channel.AddSilence();
         }
     }
-}
+}

src/Spice86.Core/Emulator/Devices/Sound/SoundChannel.cs

@@ -1,11 +1,11 @@
 namespace Spice86.Core.Emulator.Devices.Sound;
 
+using Iir.Butterworth;
+
+using SpeexResamplerSharp;
+
 using Spice86.Audio.Common;
 using Spice86.Audio.Filters;
-using Spice86.Audio.Filters.Speex;
-
-using HighPass = Audio.Filters.IirFilters.Filters.Butterworth.HighPass;
-using LowPass = Audio.Filters.IirFilters.Filters.Butterworth.LowPass;
 
 using System.Threading;
 
@@ -16,8 +16,8 @@ namespace Spice86.Core.Emulator.Devices.Sound;
 /// 2022-2025 The DOSBox Staging Team
 /// </remarks>
 public sealed class SoundChannel {
-    private const uint SpeexChannels = 2; // Always use stereo for processing
-    private const int SpeexQuality = 5; // Medium quality - good balance between CPU and quality
+    private const int SpeexChannels = 2; // Always use stereo for processing
+    private const ResamplerQuality SpeexQuality = ResamplerQuality.Desktop;
 
     private const byte EnvelopeMaxExpansionOverMs = 15; // Envelope expands over 15ms
     private const byte EnvelopeExpiresAfterSeconds = 10; // Envelope expires after 10s
@@ -48,7 +48,7 @@ public sealed class SoundChannel {
     private int _zohTargetRateHz;
 
     // Initialized ONCE when first needed (see ConfigureResampler)
-    private SpeexResamplerCSharp? _speexResampler;
+    private SpeexResampler? _speexResampler;
 
     // Pre-allocated resample buffers (avoids per-tick GC allocations)
     private float[] _resampleInputBuffer = [];
@@ -341,7 +341,7 @@ void ConfigureSpeexResampler(int inRateHz) {
             uint speexInRate = (uint)inRateHz;
             uint speexOutRate = (uint)mixerRateHz;
 
-            _speexResampler ??= new SpeexResamplerCSharp(
+            _speexResampler ??= new SpeexResampler(
                     SpeexChannels,
                     speexInRate,
                     speexOutRate,
@@ -986,7 +986,7 @@ private static float Lerp(float a, float b, float t) {
     }
 
     private void ApplySpeexResampling(int audioFramesStartingSize) {
-        if (_speexResampler is null or { IsInitialized: false }) {
+        if (_speexResampler is null) {
             throw new InvalidOperationException("Speex Resampler was null or not initialized before audio resampling");
         }
         int inFrames = _convertBuffer.Count;
@@ -1018,35 +1018,32 @@ private void ApplySpeexResampling(int audioFramesStartingSize) {
         }
 
         // Process through Speex resampler (interleaved stereo)
-        _speexResampler.ProcessInterleavedFloat(
+        ResamplerProcessResult framesGenerated = _speexResampler.ProcessInterleaved(
             _resampleInputBuffer.AsSpan(0, inputSize),
-            _resampleOutputBuffer.AsSpan(0, outputSize),
-            out uint _,
-            out uint outFramesGenerated);
+            _resampleOutputBuffer.AsSpan(0, outputSize));
 
         // Copy resampled frames back to audio_frames
         Span<AudioFrame> audioSpan = AudioFrames.AsSpan();
-        for (int i = 0; i < (int)outFramesGenerated; i++) {
+        for (int i = 0; i < framesGenerated.OutputProduced; i++) {
             audioSpan[audioFramesStartingSize + i] = new AudioFrame(
                 _resampleOutputBuffer[i * 2],
                 _resampleOutputBuffer[i * 2 + 1]);
         }
 
         // Trim audio_frames to actual size
-        int actualSize = audioFramesStartingSize + (int)outFramesGenerated;
+        int actualSize = audioFramesStartingSize + framesGenerated.OutputProduced;
         if (AudioFrames.Count > actualSize) {
             AudioFrames.RemoveRange(actualSize, AudioFrames.Count - actualSize);
         }
     }
 
-    private static int EstimateMaxOutFrames(SpeexResamplerCSharp resampler, int inFrames) {
-        resampler.GetRatio(out uint ratioNum, out uint ratioDen);
-        if (ratioNum == 0 || ratioDen == 0 || inFrames <= 0) {
+    private static int EstimateMaxOutFrames(SpeexResampler resampler, int inFrames) {
+        if (resampler.RatioNumerator == 0 || resampler.RatioDenominator == 0 || inFrames <= 0) {
             return inFrames;
         }
 
-        double numerator = (double)inFrames * ratioDen;
-        int estimated = (int)Math.Ceiling(numerator / ratioNum);
+        double numerator = (double)inFrames * resampler.RatioDenominator;
+        int estimated = (int)Math.Ceiling(numerator / resampler.RatioNumerator);
         return estimated <= 0 ? inFrames : estimated;
     }
 

src/Spice86.Core/Spice86.Core.csproj

@@ -17,7 +17,9 @@
 
     <ItemGroup>
         <PackageReference Include="CommunityToolkit.HighPerformance" />
+        <PackageReference Include="Iir1.Net" />
         <PackageReference Include="JetBrains.Annotations" />
+        <PackageReference Include="MVerb.Net" />
         <PackageReference Include="Serilog" />
         <PackageReference Include="Serilog.Sinks.File" />
         <PackageReference Include="Spectre.Console.Cli" />
@@ -27,6 +29,7 @@
         </Reference>
         <PackageReference Include="MeltySynth" />
         <PackageReference Include="Microsoft.AspNetCore.OpenApi" />
+        <PackageReference Include="SpeexResamplerSharp" />
         <PackageReference Include="Swashbuckle.AspNetCore" />
         <PackageReference Include="NukedOPL3Sharp" />
         <PackageReference Include="Spice86.Audio" />

tests/Spice86.Tests/Emulator/Devices/Sound/SoundChannelTests.cs

@@ -0,0 +1,42 @@
+namespace Spice86.Tests.Emulator.Devices.Sound;
+
+using FluentAssertions;
+
+using Spice86.Audio.Filters;
+using Spice86.Core.Emulator.Devices.Sound;
+
+using Xunit;
+
+/// <summary>
+/// Verifies sound-channel processing contracts independently from a host audio device.
+/// </summary>
+[Trait("Category", "Sound")]
+public sealed class SoundChannelTests {
+    /// <summary>
+    /// Variable producer block sizes must not expose retained resampling-buffer capacity as active input.
+    /// </summary>
+    [Fact]
+    public void AddSamplesFloat_AfterLargerBlock_ProcessesOnlyCurrentFrames() {
+        // Arrange
+        const int MixerRate = 48000;
+        const int ChannelRate = 96000;
+        const int StereoChannels = 2;
+        const int LargeFrameCount = 64;
+        const int SmallFrameCount = 1;
+        SoundChannel channel = new(_ => { }, nameof(SoundChannelTests), []);
+        channel.SetMixerSampleRate(MixerRate);
+        channel.SampleRate = ChannelRate;
+        channel.SetResampleMethod(ResampleMethod.Resample);
+        float[] largeBlock = new float[LargeFrameCount * StereoChannels];
+        float[] smallBlock = new float[SmallFrameCount * StereoChannels];
+        channel.AddSamplesFloat(LargeFrameCount, largeBlock);
+        int framesAfterLargeBlock = channel.AudioFrames.Count;
+
+        // Act
+        Action act = () => channel.AddSamplesFloat(SmallFrameCount, smallBlock);
+
+        // Assert
+        act.Should().NotThrow();
+        channel.AudioFrames.Count.Should().BeInRange(framesAfterLargeBlock, framesAfterLargeBlock + SmallFrameCount);
+    }
+}