remove libspeexdsp use in old bsnes core

src/BizHawk.Emulation.Cores/Consoles/Nintendo/SNES/LibsnesApi.cs

@@ -198,7 +198,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 		public delegate void snes_input_poll_t();
 		public delegate short snes_input_state_t(int port, int device, int index, int id);
 		public delegate void snes_input_notify_t(int index);
-		public delegate void snes_audio_sample_t(ushort left, ushort right);
+		public delegate void snes_audio_sample_t(short left, short right);
 		public delegate void snes_scanlineStart_t(int line);
 		public delegate string snes_path_request_t(int slot, string hint);
 		public delegate void snes_trace_t(uint which, string msg);

src/BizHawk.Emulation.Cores/Consoles/Nintendo/SNES/LibsnesApi_SIG.cs

@@ -45,11 +45,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 
 							if (audio_sample != null)
 							{
-								ushort* audiobuffer = ((ushort*)_comm->ptr);
+								var audiobuffer = (short*)_comm->ptr;
 								for (uint i = 0; i < nsamples;)
 								{
-									ushort left = audiobuffer[i++];
-									ushort right = audiobuffer[i++];
+									var left = audiobuffer[i++];
+									var right = audiobuffer[i++];
 									audio_sample(left, right);
 								}
 							}

src/BizHawk.Emulation.Cores/Consoles/Nintendo/SNES/LibsnesCore.IEmulator.cs

@@ -79,6 +79,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 				LagCount++;
 			}
 
+			if (renderSound)
+			{
+				ProcessSoundEnd();
+			}
+
 			return true;
 		}
 
@@ -106,7 +111,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 			}
 
 			Api.Dispose();
-			_resampler.Dispose();
+			_blipL.Dispose();
+			_blipR.Dispose();
 
 			_disposed = true;
 		}

src/BizHawk.Emulation.Cores/Consoles/Nintendo/SNES/LibsnesCore.ISoundProvider.cs

@@ -0,0 +1,83 @@
+using System;
+using BizHawk.Emulation.Common;
+
+namespace BizHawk.Emulation.Cores.Nintendo.SNES
+{
+	public partial class LibsnesCore : ISoundProvider
+	{
+		private readonly BlipBuffer _blipL = new(4096);
+		private readonly BlipBuffer _blipR = new(4096);
+		private short _latchL, _latchR;
+		private readonly short[] _sampleBuffer = new short[4096];
+		private uint _inSamps;
+		private int _outSamps;
+
+		public void DiscardSamples()
+		{
+			_outSamps = 0;
+		}
+
+		public void GetSamplesSync(out short[] samples, out int nsamp)
+		{
+			samples = _sampleBuffer;
+			nsamp = _outSamps;
+			DiscardSamples();
+		}
+
+		private void InitAudio()
+		{
+			_blipL.SetRates(32040.5, 44100);
+			_blipR.SetRates(32040.5, 44100);
+		}
+
+		private void snes_audio_sample(short left, short right)
+		{
+			if (_latchL != left)
+			{
+				_blipL.AddDelta(_inSamps, _latchL - left);
+				_latchL = left;
+			}
+
+			if (_latchR != right)
+			{
+				_blipR.AddDelta(_inSamps, _latchR - right);
+				_latchR = right;
+			}
+
+			_inSamps++;
+		}
+
+		private void ProcessSoundEnd()
+		{
+			_blipL.EndFrame(_inSamps);
+			_blipR.EndFrame(_inSamps);
+			_inSamps = 0;
+
+			_outSamps = _blipL.SamplesAvailable();
+			if (_outSamps != _blipR.SamplesAvailable())
+			{
+				throw new InvalidOperationException("Audio processing error");
+			}
+
+			_blipL.ReadSamplesLeft(_sampleBuffer, _outSamps);
+			_blipR.ReadSamplesRight(_sampleBuffer, _outSamps);
+		}
+
+		public bool CanProvideAsync => false;
+
+		public void GetSamplesAsync(short[] samples)
+		{
+			throw new InvalidOperationException("Async mode is not supported.");
+		}
+
+		public SyncSoundMode SyncMode => SyncSoundMode.Sync;
+
+		public void SetSyncMode(SyncSoundMode mode)
+		{
+			if (mode == SyncSoundMode.Async)
+			{
+				throw new NotSupportedException("Async mode is not supported.");
+			}
+		}
+	}
+}

src/BizHawk.Emulation.Cores/Consoles/Nintendo/SNES/LibsnesCore.cs

@@ -100,7 +100,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 
 			// start up audio resampler
 			InitAudio();
-			ser.Register<ISoundProvider>(_resampler);
 
 			// strip header
 			if ((romData?.Length & 0x7FFF) == 512)
@@ -218,7 +217,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 
 		private IController _controller;
 		private readonly LoadParams _currLoadParams;
-		private SpeexResampler _resampler;
 		private int _timeFrameCounter;
 		private bool _disposed;
 
@@ -623,16 +621,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 		//  return ret;
 		//}
 
-		private void InitAudio()
-		{
-			_resampler = new SpeexResampler((SpeexResampler.Quality)6, 64081, 88200, 32041, 44100);
-		}
-
-		private void snes_audio_sample(ushort left, ushort right)
-		{
-			_resampler.EnqueueSample((short)left, (short)right);
-		}
-
 		private void RefreshPalette()
 		{
 			CurrPalette = (SnesColors.ColorType)Enum.Parse(typeof(SnesColors.ColorType), _settings.Palette, false);