Implement auto-mute to improve uncomfortable audio distortion while host is lagging

src/BizHawk.Client.Common/config/Config.cs

@@ -255,6 +255,12 @@ public void ResolveDefaults()
 		public string SoundDevice { get; set; } = "";
 		public int SoundBufferSizeMs { get; set; } = 100;
 
+		public bool MuteInBG { get; set; } = false;
+
+		public bool MuteOnLag { get; set; } = false;
+
+		public int FPSThresholdPercentage { get; set; } = 90;
+
 		// Lua
 		public RecentFiles RecentLua { get; set; } = new RecentFiles(8);
 		public RecentFiles RecentLuaSession { get; set; } = new RecentFiles(8);

src/BizHawk.Client.EmuHawk/MainForm.cs

@@ -3302,6 +3302,28 @@ private void StepRunLoop_Core(bool force = false)
 				UpdateToolsAfter();
 			}
 
+			// Mutes the game if EmuHawk is unfocused or minimized
+			// An option in the sound settings needs to be turned on for this to work.
+			if (Config.MuteInBG && (WindowState == FormWindowState.Minimized || Form.ActiveForm == null))
+			{
+				Sound.StopSound();
+			}
+			else
+			{
+				Sound.StartSound();
+			}
+
+			// Mutes the game if the current FPS reaches the threshold chosen by the user or lower
+			// An option in the sound settings needs to be turned on for this to work.
+			if (Config.MuteOnLag && _lastFps <= PlatformFrameRates.GetFrameRate(Emulator.SystemId, Emulator.HasRegions() && Emulator.AsRegionable().Region is DisplayType.PAL) * ((double)Config.FPSThresholdPercentage / 100))
+			{
+				Sound.StopSound();
+			}
+			else
+			{
+				Sound.StartSound();
+			}
+
 			Sound.UpdateSound(atten, DisableSecondaryThrottling);
 		}
 

src/BizHawk.Client.EmuHawk/Program.cs

@@ -33,7 +33,7 @@ static Program()
 			// This needs to be done before the warnings/errors show up
 			Application.EnableVisualStyles();
 			Application.SetCompatibleTextRenderingDefault(false);
-
+			
 			// Quickly check if the user is running this as a 32 bit process somehow
 			// TODO: We may want to remove this sometime, EmuHawk should be able to run somewhat as 32 bit if the user really wants to
 			// (There are no longer any hard 64 bit deps, i.e. SlimDX is no longer around)

src/BizHawk.Client.EmuHawk/Sound/Sound.cs

@@ -188,7 +188,6 @@ public void UpdateSound(float atten, bool isSecondaryThrottlingDisabled)
 					{
 						return;
 					}
-
 					int samplesPerMs = SampleRate / 1000;
 					int outputThresholdMs = 20;
 					while (sampleCount > samplesNeeded)