Move VsyncNum and VsyncDen out of CoreComm and into IVideoProvider

BizHawk.Client.Common/BitmapBufferVideoProvider.cs

@@ -52,5 +52,15 @@ namespace BizHawk.Client.Common
 		{
 			get { return 0; }
 		}
+
+		public int VsyncNum
+		{
+			get { throw new InvalidOperationException(); }
+		}
+
+		public int VsyncDen
+		{
+			get { throw new InvalidOperationException(); }
+		}
 	}
 }

BizHawk.Client.Common/QuickBmpFile.cs

@@ -221,6 +221,16 @@ namespace BizHawk.Client.Common
 			public int BufferWidth { get; set; }
 			public int BufferHeight { get; set; }
 			public int BackgroundColor => unchecked((int)0xff000000);
+
+			public int VsyncNum
+			{
+				get { throw new InvalidOperationException(); }
+			}
+
+			public int VsyncDen
+			{
+				get { throw new InvalidOperationException(); }
+			}
 		}
 
 		public static unsafe bool Load(IVideoProvider v, Stream s)

BizHawk.Client.EmuHawk/AVOut/AviWriter.cs

@@ -112,6 +112,8 @@ namespace BizHawk.Client.EmuHawk
 			public int BufferWidth { get; }
 			public int BufferHeight { get; }
 			public int BackgroundColor { get; }
+			public int VsyncNum { get; }
+			public int VsyncDen { get; }
 			public VideoCopy(IVideoProvider c)
 			{
 				_vb = (int[])c.GetVideoBuffer().Clone();
@@ -120,6 +122,8 @@ namespace BizHawk.Client.EmuHawk
 				BackgroundColor = c.BackgroundColor;
 				VirtualWidth = c.VirtualWidth;
 				VirtualHeight = c.VirtualHeight;
+				VsyncNum = c.VsyncNum;
+				VsyncDen = c.VsyncDen;
 			}
 
 			public int[] GetVideoBuffer()
@@ -128,7 +132,6 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
-
 		/// <summary>
 		/// opens an avi file for recording with the supplied enumerator used to name files.
 		/// set a video codec token first.

BizHawk.Client.EmuHawk/AVOut/BmpVideoProvder.cs

@@ -49,5 +49,15 @@ namespace BizHawk.Client.EmuHawk
 		public int BufferHeight => _bmp.Height;
 
 		public int BackgroundColor => 0;
+
+		public int VsyncNum
+		{
+			get { throw new InvalidOperationException(); }
+		}
+
+		public int VsyncDen
+		{
+			get { throw new InvalidOperationException(); }
+		}
 	}
 }

BizHawk.Client.EmuHawk/DisplayManager/DisplayManager.cs

@@ -416,6 +416,16 @@ namespace BizHawk.Client.EmuHawk
 			public int BufferWidth { get; set; }
 			public int BufferHeight { get; set; }
 			public int BackgroundColor { get; set; }
+
+			public int VsyncNum
+			{
+				get { throw new InvalidOperationException(); }
+			}
+
+			public int VsyncDen
+			{
+				get { throw new InvalidOperationException(); }
+			}
 		}
 
 		void FixRatio(float x, float y, int inw, int inh, out int outw, out int outh)

BizHawk.Client.EmuHawk/MainForm.cs

@@ -1861,7 +1861,7 @@ namespace BizHawk.Client.EmuHawk
 			Global.DisableSecondaryThrottling = _unthrottled || turbo || fastForward || rewind;
 
 			// realtime throttle is never going to be so exact that using a double here is wrong
-			_throttle.SetCoreFps(Emulator.CoreComm.VsyncRate);
+			_throttle.SetCoreFps(Emulator.VsyncRate());
 			_throttle.signal_paused = EmulatorPaused;
 			_throttle.signal_unthrottle = _unthrottled || turbo;
 			//zero 26-mar-2016 - vsync and vsync throttle here both is odd, but see comments elsewhere about triple buffering
@@ -3034,7 +3034,7 @@ namespace BizHawk.Client.EmuHawk
 					aw = new AudioStretcher(aw);
 				}
 
-				aw.SetMovieParameters(Emulator.CoreComm.VsyncNum, Emulator.CoreComm.VsyncDen);
+				aw.SetMovieParameters(Emulator.VsyncNum(), Emulator.VsyncDen());
 				if (_avwriterResizew > 0 && _avwriterResizeh > 0)
 				{
 					aw.SetVideoParameters(_avwriterResizew, _avwriterResizeh);

BizHawk.Client.EmuHawk/Sound/Sound.cs

@@ -2,6 +2,7 @@
 using System.Threading;
 
 using BizHawk.Emulation.Common;
+using BizHawk.Emulation.Common.IEmulatorExtensions;
 using BizHawk.Client.Common;
 
 namespace BizHawk.Client.EmuHawk
@@ -99,7 +100,7 @@ namespace BizHawk.Client.EmuHawk
 			}
 			else if (source.SyncMode == SyncSoundMode.Async)
 			{
-				_bufferedAsync.RecalculateMagic(Global.Emulator.CoreComm.VsyncRate);
+				_bufferedAsync.RecalculateMagic(Global.Emulator.VsyncRate());
 				_bufferedProvider = _bufferedAsync;
 			}
 			else throw new InvalidOperationException("Unsupported sync mode.");
@@ -112,7 +113,7 @@ namespace BizHawk.Client.EmuHawk
 		internal void HandleInitializationOrUnderrun(bool isUnderrun, ref int samplesNeeded)
 		{
 			// Fill device buffer with silence but leave enough room for one frame
-			int samplesPerFrame = (int)Math.Round(SampleRate / Global.Emulator.CoreComm.VsyncRate);
+			int samplesPerFrame = (int)Math.Round(SampleRate / (double)Global.Emulator.VsyncRate());
 			int silenceSamples = Math.Max(samplesNeeded - samplesPerFrame, 0);
 			_outputDevice.WriteSamples(new short[silenceSamples * 2], silenceSamples);
 			samplesNeeded -= silenceSamples;

BizHawk.Client.EmuHawk/Sound/Utilities/SoundOutputProvider.cs

@@ -4,6 +4,7 @@ using System.Linq;
 
 using BizHawk.Client.Common;
 using BizHawk.Emulation.Common;
+using BizHawk.Emulation.Common.IEmulatorExtensions;
 
 namespace BizHawk.Client.EmuHawk
 {
@@ -120,7 +121,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private double AdvertisedSamplesPerFrame
 		{
-			get { return SampleRate / Global.Emulator.CoreComm.VsyncRate; }
+			get { return SampleRate / Global.Emulator.VsyncRate(); }
 		}
 
 		public void GetSamples(short[] samples)

BizHawk.Client.MultiHawk/DisplayManager/DisplayManager.cs

@@ -282,6 +282,16 @@ namespace BizHawk.Client.MultiHawk
 			public int BufferWidth { get; set; }
 			public int BufferHeight { get; set; }
 			public int BackgroundColor { get; set; }
+
+			public int VsyncNum
+			{
+				get { throw new InvalidOperationException(); }
+			}
+
+			public int VsyncDen
+			{
+				get { throw new InvalidOperationException(); }
+			}
 		}
 
 		void FixRatio(float x, float y, int inw, int inh, out int outw, out int outh)

BizHawk.Client.MultiHawk/Mainform.cs

@@ -956,7 +956,7 @@ namespace BizHawk.Client.MultiHawk
 			Global.DisableSecondaryThrottling = /*_unthrottled || TODO */ turbo || fastForward;
 
 			// realtime throttle is never going to be so exact that using a double here is wrong
-			_throttle.SetCoreFps(EmulatorWindows.Master.Emulator.CoreComm.VsyncRate);
+			_throttle.SetCoreFps(EmulatorWindows.Master.Emulator.VsyncRate());
 			_throttle.signal_paused = EmulatorPaused;
 			_throttle.signal_unthrottle = /*_unthrottled || TODO */ turbo;
 			_throttle.signal_overrideSecondaryThrottle = fastForward && (Global.Config.SoundThrottle || Global.Config.VSyncThrottle || Global.Config.VSync);

BizHawk.Emulation.Common/Base Implementations/NullEmulator.cs

@@ -110,6 +110,10 @@ namespace BizHawk.Emulation.Common
 
 		public int BackgroundColor => NullVideo.DefaultBackgroundColor;
 
+		public int VsyncNum => NullVideo.DefaultVsyncNum;
+
+		public int VsyncDen => NullVideo.DefaultVsyncDen;
+
 		#endregion
 
 		#region ISoundProvider

BizHawk.Emulation.Common/Base Implementations/NullVideo.cs

@@ -17,6 +17,8 @@
 		public static int DefaultWidth { get; } = 256;
 		public static int DefaultHeight { get; } = 192;
 		public static int DefaultBackgroundColor { get; } = 0;
+		public static int DefaultVsyncNum { get; } = 60;
+		public static int DefaultVsyncDen { get; } = 1;
 
 		public int VirtualWidth => DefaultWidth;
 
@@ -27,5 +29,9 @@
 		public int BufferHeight => DefaultHeight;
 
 		public int BackgroundColor => DefaultBackgroundColor;
+
+		public int VsyncNum => DefaultVsyncNum;
+
+		public int VsyncDen => DefaultVsyncDen;
 	}
 }

BizHawk.Emulation.Common/CoreComms.cs

@@ -19,11 +19,6 @@ namespace BizHawk.Emulation.Common
 
 		public ICoreFileProvider CoreFileProvider { get; set; }
 
-		public double VsyncRate => VsyncNum / (double)VsyncDen;
-
-		public int VsyncNum { get; set; } = 60;
-		public int VsyncDen { get; set; } = 1;
-
 		// a core should set these if you wish to provide rom status information yourself. otherwise it will be calculated by the frontend in a way you may not like, using RomGame-related concepts.
 		public string RomStatusAnnotation { get; set; }
 		public string RomStatusDetails { get; set; }

BizHawk.Emulation.Common/Extensions.cs

@@ -65,7 +65,7 @@ namespace BizHawk.Emulation.Common.IEmulatorExtensions
 		public static ISoundProvider AsSoundProviderOrDefault(this IEmulator core)
 		{
 			return core.ServiceProvider.GetService<ISoundProvider>()
-				?? CachedNullSoundProviders.GetValue(core, e => new NullSound(e.CoreComm.VsyncNum, e.CoreComm.VsyncDen));
+				?? CachedNullSoundProviders.GetValue(core, e => new NullSound(core.VsyncNum(), core.VsyncDen()));
 		}
 
 		public static bool HasMemoryDomains(this IEmulator core)
@@ -262,7 +262,7 @@ namespace BizHawk.Emulation.Common.IEmulatorExtensions
 			{
 				return false;
 			}
-			
+
 			// once upon a time, we did a try { poke(peek) } here, but that was before Writable was added. the poke(peek) is not acceptable. If there are further problems, make sure Writable is correct.
 			return true;
 		}
@@ -342,6 +342,31 @@ namespace BizHawk.Emulation.Common.IEmulatorExtensions
 			return core.ServiceProvider.GetService<IBoardInfo>();
 		}
 
+		public static int VsyncNum(this IEmulator core)
+		{
+			if (core != null && core.HasVideoProvider())
+			{
+				//return core.AsVideoProvider().VsyncNum
+			}
+
+			return 60;
+		}
+
+		public static int VsyncDen(this IEmulator core)
+		{
+			if (core != null && core.HasVideoProvider())
+			{
+				//return core.AsVideoProvider().VsyncDen
+			}
+
+			return 1;
+		}
+
+		public static int VsyncRate(this IEmulator core)
+		{
+			return core.VsyncNum() / core.VsyncDen();
+		}
+
 		// TODO: a better place for these
 		public static bool IsImplemented(this MethodInfo info)
 		{
@@ -366,4 +391,4 @@ namespace BizHawk.Emulation.Common.IEmulatorExtensions
 			return !info.GetCustomAttributes(false).Any(a => a is FeatureNotImplemented);
 		}
 	}
-}
+}

BizHawk.Emulation.Common/Interfaces/Services/IVideoProvider.cs

@@ -44,6 +44,16 @@
 		/// </summary>
 		int BufferHeight { get; }
 
+		/// <summary>
+		/// Gets the vsync Numerator. Combined with the <seealso cref="VsyncDen"/> can be used to calculate a precise vsync rate.
+		/// </summary>
+		int VsyncNum { get; }
+
+		/// <summary>
+		/// Gets the vsync Denominator. Combined with the <seealso cref="VsyncDen"/> can be used to calculate a precise vsync rate.
+		/// </summary>
+		int VsyncDen { get; }
+
 		/// <summary>
 		/// Gets the default color when no other color is applied
 		/// Often cores will set this to something other than black

BizHawk.Emulation.Cores/Calculator/TI83.IVideoProvider.cs

@@ -9,6 +9,8 @@ namespace BizHawk.Emulation.Cores.Calculators
 		public int BufferWidth => 96;
 		public int BufferHeight => 64;
 		public int BackgroundColor => 0;
+		public int VsyncNum => NullVideo.DefaultVsyncNum;
+		public int VsyncDen => NullVideo.DefaultVsyncDen;
 
 		public int[] GetVideoBuffer()
 		{

BizHawk.Emulation.Cores/Computers/AppleII/AppleII.IVideoProvider.cs

@@ -18,5 +18,23 @@ namespace BizHawk.Emulation.Cores.Computers.AppleII
 		public int BufferWidth => 560;
 		public int BufferHeight => 384;
 		public int BackgroundColor => 0;
+
+		public int VsyncNum
+		{
+			[FeatureNotImplemented] // TODO: precise numbers or confirm the default is okay
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented] // TODO: precise numbers or confirm the default is okay
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
 	}
 }

BizHawk.Emulation.Cores/Computers/Commodore64/C64.cs

@@ -244,10 +244,6 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64
 			_board = new Motherboard(this, initRegion, borderType, sidType, tapeDriveType, diskDriveType);
 			InitRoms(diskDriveType);
 			_board.Init();
-
-			// configure video
-			CoreComm.VsyncDen = _board.Vic.CyclesPerFrame;
-			CoreComm.VsyncNum = _board.Vic.CyclesPerSecond;
 		}
 
 		private void InitMedia()

BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Vic.VideoProvider.cs

@@ -70,5 +70,11 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
 
 		[SaveState.DoNotSave]
 		public int VirtualHeight { get; private set; }
+
+		[SaveState.DoNotSave]
+		public int VsyncNum => CyclesPerFrame;
+
+		[SaveState.DoNotSave]
+		public int VsyncDen => CyclesPerSecond;
 	}
 }

BizHawk.Emulation.Cores/Consoles/Atari/2600/Atari2600.Core.cs

@@ -310,13 +310,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			}
 
 			// dcfilter coefficent is from real observed hardware behavior: a latched "1" will fully decay by ~170 or so tia sound cycles
-			_tia = new TIA(this, _pal, Settings.SECAMColors, CoreComm.VsyncRate > 55.0 ? 735 : 882);
-
-			int vsyncNum, vsyncDen;
-			_tia.GetFrameRate(out vsyncNum, out vsyncDen);
-
-			CoreComm.VsyncNum = vsyncNum;
-			CoreComm.VsyncDen = vsyncDen;
+			_tia = new TIA(this, _pal, Settings.SECAMColors);
 
 			_dcfilter = new DCFilter(_tia, 256);
 

BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/TIA.cs

@@ -14,6 +14,8 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 
 		private const int BackColor = unchecked((int)0xff000000);
 
+		private int _vsyncNum, _vsyncDen;
+
 		static TIA()
 		{
 			// add alpha to palette entries
@@ -234,7 +236,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 
 		public int NominalNumScanlines => _pal ? 312 : 262;
 
-		public void GetFrameRate(out int num, out int den)
+		private void CalcFrameRate()
 		{
 			// TODO when sound timing is made exact:
 			// NTSC refclock is actually 315 / 88 mhz
@@ -243,8 +245,8 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			int clockrate = _pal ? 3546895 : 3579545;
 			int clocksperframe = 228 * NominalNumScanlines;
 			int gcd = (int)BigInteger.GreatestCommonDivisor(clockrate, clocksperframe);
-			num = clockrate / gcd;
-			den = clocksperframe / gcd;
+			_vsyncNum = clockrate / gcd;
+			_vsyncDen = clocksperframe / gcd;
 		}
 
 		private const int ScreenWidth = 160;
@@ -325,14 +327,18 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 		//public byte[] current_audio_register = new byte[6];
 		public short[] _local_audio_cycles = new short[2000];
 
-		public TIA(Atari2600 core, bool pal, bool secam, int spf)
+		public TIA(Atari2600 core, bool pal, bool secam)
 		{
 			_core = core;
 			_player0.ScanCnt = 8;
 			_player1.ScanCnt = 8;
 			_pal = pal;
 			SetSECAM(secam);
-			_spf = spf;
+			
+
+			CalcFrameRate();
+
+			_spf = _vsyncNum / (double)_vsyncDen > 55.0 ? 735 : 882;
 		}
 
 		public void SetSECAM(bool secam)
@@ -387,6 +393,10 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 
 		public int BackgroundColor => _core.Settings.BackgroundColor.ToArgb();
 
+		public int VsyncNum => _vsyncNum;
+
+		public int VsyncDen => _vsyncDen;
+
 		public int[] GetVideoBuffer()
 		{
 			return FrameBuffer;

BizHawk.Emulation.Cores/Consoles/Atari/7800/Atari7800.cs

@@ -205,10 +205,6 @@ namespace BizHawk.Emulation.Cores.Atari.Atari7800
 
 			_avProvider.ConnectToMachine(theMachine, GameInfo);
 
-			// to sync exactly with audio as this emulator creates and times it, the frame rate should be exactly 60:1 or 50:1
-			CoreComm.VsyncNum = theMachine.FrameHZ;
-			CoreComm.VsyncDen = 1;
-
 			SetupMemoryDomains(hsc7800);
 		}
 
@@ -218,9 +214,13 @@ namespace BizHawk.Emulation.Cores.Atari.Atari7800
 
 		private class MyAVProvider : IVideoProvider, ISoundProvider, IDisposable
 		{
+			// to sync exactly with audio as this emulator creates and times it, the frame rate should be exactly 60:1 or 50:1
+			private int _frameHz;
+
 			public FrameBuffer Framebuffer { get; private set; }
 			public void ConnectToMachine(MachineBase m, EMU7800.Win.GameProgram g)
 			{
+				_frameHz = m.FrameHZ;
 				Framebuffer = m.CreateFrameBuffer();
 				BufferWidth = Framebuffer.VisiblePitch;
 				BufferHeight = Framebuffer.Scanlines;
@@ -281,6 +281,8 @@ namespace BizHawk.Emulation.Cores.Atari.Atari7800
 			public int BufferWidth { get; private set; }
 			public int BufferHeight { get; private set; }
 			public int BackgroundColor => unchecked((int)0xff000000);
+			public int VsyncNum => _frameHz;
+			public int VsyncDen => 1;
 
 			#region ISoundProvider
 

BizHawk.Emulation.Cores/Consoles/Atari/lynx/Lynx.IVideoProvider.cs

@@ -23,5 +23,9 @@ namespace BizHawk.Emulation.Cores.Atari.Lynx
 		public int BufferHeight { get; }
 
 		public int BackgroundColor => unchecked((int)0xff000000);
+
+		public int VsyncNum => 16000000; // 16.00 mhz refclock
+
+		public int VsyncDen => 16 * 105 * 159;
 	}
 }

BizHawk.Emulation.Cores/Consoles/Atari/lynx/Lynx.cs

@@ -94,9 +94,6 @@ namespace BizHawk.Emulation.Cores.Atari.Lynx
 			Core = LibLynx.Create(realfile, realfile.Length, bios, bios.Length, pagesize0, pagesize1, false);
 			try
 			{
-				CoreComm.VsyncNum = 16000000; // 16.00 mhz refclock
-				CoreComm.VsyncDen = 16 * 105 * 159;
-
 				_savebuff = new byte[LibLynx.BinStateSize(Core)];
 				_savebuff2 = new byte[_savebuff.Length + 13];
 

BizHawk.Emulation.Cores/Consoles/Coleco/TMS9918A.cs

@@ -465,6 +465,24 @@ namespace BizHawk.Emulation.Cores.ColecoVision
 		public int BufferHeight => 192;
 		public int BackgroundColor => 0;
 
+		public int VsyncNum
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
+
 		private readonly int[] PaletteTMS9918 =
 		{
 			unchecked((int)0xFF000000),

BizHawk.Emulation.Cores/Consoles/Intellivision/STIC.cs

@@ -82,6 +82,24 @@ namespace BizHawk.Emulation.Cores.Intellivision
 		public int BufferHeight => 208;
 		public int BackgroundColor => 0;
 
+		public int VsyncNum
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
+
 		public void Reset()
 		{
 			Sr1 = true;

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IVideoProvider.cs

@@ -17,6 +17,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 
 		public int BackgroundColor => unchecked((int)0xff000000);
 
+
+		public int VsyncNum => 262144;
+
+		public int VsyncDen => 4389;
+
 		private readonly int[] _videobuff = new int[240 * 160];
 	}
 }

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.cs

@@ -52,9 +52,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 
 				ServiceProvider = ser;
 				CoreComm = comm;
-
-				CoreComm.VsyncNum = 262144;
-				CoreComm.VsyncDen = 4389;
 				CoreComm.NominalWidth = 240;
 				CoreComm.NominalHeight = 160;
 				PutSettings(_settings);

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/VBANext.IVideoProvider.cs

@@ -19,6 +19,10 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			return _videobuff;
 		}
 
+		public int VsyncNum => 262144;
+
+		public int VsyncDen => 4389;
+
 		private readonly int[] _videobuff = new int[240 * 160];
 		private readonly int[] _videopalette = new int[65536];
 

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/VBANext.cs

@@ -71,8 +71,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 				};
 				ser.Register<ITraceable>(Tracer);
 
-				CoreComm.VsyncNum = 262144;
-				CoreComm.VsyncDen = 4389;
 				CoreComm.NominalWidth = 240;
 				CoreComm.NominalHeight = 160;
 

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/Gambatte.IVideoProvider.cs

@@ -21,5 +21,9 @@
 		public int BufferHeight => 144;
 
 		public int BackgroundColor => 0;
+
+		public int VsyncNum => 262144;
+
+		public int VsyncDen => 4389;
 	}
 }

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/Gambatte.cs

@@ -104,8 +104,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 			InitMemoryCallbacks();
 			CoreComm = comm;
 
-			comm.VsyncNum = 262144;
-			comm.VsyncDen = 4389;
 			comm.RomStatusAnnotation = null;
 			comm.RomStatusDetails = null;
 			comm.NominalWidth = 160;

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/GambatteLink.IVideoProvider.cs

@@ -10,6 +10,10 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 		public int BufferWidth { get { return 320; } }
 		public int BufferHeight { get { return 144; } }
 
+		public int VsyncNum => L.VsyncNum;
+
+		public int VsyncDen => L.VsyncDen;
+
 		public int BackgroundColor
 		{
 			get { return unchecked((int)0xff000000); }

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/GambatteLink.cs

@@ -31,8 +31,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 			L.ConnectMemoryCallbackSystem(_memorycallbacks);
 			R.ConnectMemoryCallbackSystem(_memorycallbacks);
 
-			comm.VsyncNum = L.CoreComm.VsyncNum;
-			comm.VsyncDen = L.CoreComm.VsyncDen;
 			comm.RomStatusAnnotation = null;
 			comm.RomStatusDetails = "LEFT:\r\n" + L.CoreComm.RomStatusDetails + "RIGHT:\r\n" + R.CoreComm.RomStatusDetails;
 			comm.NominalWidth = L.CoreComm.NominalWidth + R.CoreComm.NominalWidth;

BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64.cs

@@ -103,17 +103,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64
 					_display_type = DisplayType.NTSC;
 					break;
 			}
-			switch (Region)
-			{
-				case DisplayType.NTSC:
-					comm.VsyncNum = 60000;
-					comm.VsyncDen = 1001;
-					break;
-				default:
-					comm.VsyncNum = 50;
-					comm.VsyncDen = 1;
-					break;
-			}
 
 			StartThreadLoop();
 
@@ -134,6 +123,18 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64
 			(ServiceProvider as BasicServiceProvider).Register<IVideoProvider>(_videoProvider);
 			(ServiceProvider as BasicServiceProvider).Register<ISoundProvider>(_audioProvider.Resampler);
 
+			switch (Region)
+			{
+				case DisplayType.NTSC:
+					_videoProvider.VsyncNum = 60000;
+					_videoProvider.VsyncDen = 1001;
+					break;
+				default:
+					_videoProvider.VsyncNum = 50;
+					_videoProvider.VsyncDen = 1;
+					break;
+			}
+
 			string rsp;
 			switch (_syncSettings.Rsp)
 			{

BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64VideoProvider.cs

@@ -43,6 +43,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64
 		public int BufferWidth { get; private set; }
 		public int BufferHeight { get; private set; }
 		public int BackgroundColor { get { return 0; } }
+		public int VsyncNum { get; internal set; }
+		public int VsyncDen { get; internal set; }
 
 		/// <summary>
 		/// Fetches current frame buffer from mupen64

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs

@@ -211,8 +211,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				case Common.DisplayType.PAL:
 					apu = new APU(this, apu, true);
 					ppu.region = PPU.Region.PAL;
-					CoreComm.VsyncNum = 50;
-					CoreComm.VsyncDen = 1;
+					VsyncNum = 50;
+					VsyncDen = 1;
 					cpuclockrate = 1662607;
 					cpu_sequence = cpu_sequence_PAL;
 					_display_type = DisplayType.PAL;
@@ -220,8 +220,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				case Common.DisplayType.NTSC:
 					apu = new APU(this, apu, false);
 					ppu.region = PPU.Region.NTSC;
-					CoreComm.VsyncNum = 39375000;
-					CoreComm.VsyncDen = 655171;
+					VsyncNum = 39375000;
+					VsyncDen = 655171;
 					cpuclockrate = 1789773;
 					cpu_sequence = cpu_sequence_NTSC;
 					break;
@@ -229,8 +229,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				case Common.DisplayType.Dendy:
 					apu = new APU(this, apu, false);
 					ppu.region = PPU.Region.Dendy;
-					CoreComm.VsyncNum = 50;
-					CoreComm.VsyncDen = 1;
+					VsyncNum = 50;
+					VsyncDen = 1;
 					cpuclockrate = 1773448;
 					cpu_sequence = cpu_sequence_NTSC;
 					_display_type = DisplayType.Dendy;
@@ -246,7 +246,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 			// apu has some specific power up bahaviour that we will emulate here
 			apu.NESHardReset();
 
-
 			if (SyncSettings.InitialWRamStatePattern != null && SyncSettings.InitialWRamStatePattern.Any())
 			{
 				for (int i = 0; i < 0x800; i++)
@@ -291,6 +290,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		}
 
+		private int VsyncNum { get; set; }
+		private int VsyncDen { get; set; }
+
 		private IController _controller;
 
 		bool resetSignal;

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.cs

@@ -337,6 +337,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				}
 			}
 
+			public int VsyncNum => emu.VsyncNum;
+			public int VsyncDen => emu.VsyncDen;
 		}
 
 		MyVideoProvider videoProvider;

BizHawk.Emulation.Cores/Consoles/Nintendo/QuickNES/QuickNES.IVideoProvider.cs

@@ -8,6 +8,9 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.QuickNES
 		public int BufferHeight { get; private set; }
 		public int BackgroundColor { get { return unchecked((int)0xff000000); } }
 
+		public int VsyncNum => 39375000;
+		public int VsyncDen => 655171;
+
 		public int[] GetVideoBuffer()
 		{
 			return VideoOutput;

BizHawk.Emulation.Cores/Consoles/Nintendo/QuickNES/QuickNES.cs

@@ -56,8 +56,6 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.QuickNES
 					string mappername = Marshal.PtrToStringAnsi(QN.qn_get_mapper(Context, ref mapper));
 					Console.WriteLine("QuickNES: Booted with Mapper #{0} \"{1}\"", mapper, mappername);
 					BoardName = mappername;
-					CoreComm.VsyncNum = 39375000;
-					CoreComm.VsyncDen = 655171;
 					PutSettings((QuickNESSettings)Settings ?? new QuickNESSettings());
 
 					_syncSettings = (QuickNESSyncSettings)SyncSettings ?? new QuickNESSyncSettings();

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

@@ -19,6 +19,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 			return _videoBuffer;
 		}
 
+		public int VsyncNum { get; }
+		public int VsyncDen { get; }
+
 		private int[] _videoBuffer = new int[256 * 224];
 		private int _videoWidth = 256;
 		private int _videoHeight = 224;

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

@@ -156,14 +156,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 			if (Api.Region == LibsnesApi.SNES_REGION.NTSC)
 			{
 				// similar to what aviout reports from snes9x and seems logical from bsnes first principles. bsnes uses that numerator (ntsc master clockrate) for sure.
-				CoreComm.VsyncNum = 21477272;
-				CoreComm.VsyncDen = 4 * 341 * 262;
+				VsyncNum = 21477272;
+				VsyncDen = 4 * 341 * 262;
 			}
 			else
 			{
 				// http://forums.nesdev.com/viewtopic.php?t=5367&start=19
-				CoreComm.VsyncNum = 21281370;
-				CoreComm.VsyncDen = 4 * 341 * 312;
+				VsyncNum = 21281370;
+				VsyncDen = 4 * 341 * 312;
 			}
 
 			Api.CMD_power();

BizHawk.Emulation.Cores/Consoles/Nintendo/SNES9X/Snes9x.cs

@@ -66,6 +66,24 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES9X
 		public int BufferHeight { get { return 224; } }
 		public int BackgroundColor { get { return unchecked((int)0xff000000); } }
 
+		public int VsyncNum
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
+
 		#endregion
 
 		#region ISoundProvider

BizHawk.Emulation.Cores/Consoles/PC Engine/VDC.Render.cs

@@ -1,4 +1,5 @@
 using System;
+using BizHawk.Emulation.Common;
 
 namespace BizHawk.Emulation.Cores.PCEngine
 {
@@ -439,5 +440,23 @@ namespace BizHawk.Emulation.Cores.PCEngine
 		public int BufferWidth => FramePitch;
 		public int BufferHeight => FrameHeight;
 		public int BackgroundColor => vce.Palette[256];
+
+		public int VsyncNum
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
 	}
 }

BizHawk.Emulation.Cores/Consoles/PC Engine/VPC.cs

@@ -528,5 +528,23 @@ namespace BizHawk.Emulation.Cores.PCEngine
 		public int BufferWidth => FrameWidth;
 		public int BufferHeight => FrameHeight;
 		public int BackgroundColor => VCE.Palette[0];
+
+		public int VsyncNum
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
 	}
 }

BizHawk.Emulation.Cores/Consoles/Sega/SMS/SMS.cs

@@ -94,9 +94,6 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 				Region = DisplayType.NTSC; // all game gears run at 60hz/NTSC mode
 			}
 
-			CoreComm.VsyncNum = Region == DisplayType.NTSC ? 60 : 50;
-			CoreComm.VsyncDen = 1;
-
 			RegionStr = SyncSettings.ConsoleRegion;
 			if (RegionStr == "Auto")
 			{

BizHawk.Emulation.Cores/Consoles/Sega/SMS/VDP.cs

@@ -496,5 +496,9 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 		{
 			get { return Palette[BackdropColor]; }
 		}
+
+		public int VsyncNum => DisplayType == DisplayType.NTSC ? 60 : 50;
+
+		public int VsyncDen => 1;
 	}
 }

BizHawk.Emulation.Cores/Consoles/Sega/Saturn/Yabause.cs

@@ -346,6 +346,24 @@ namespace BizHawk.Emulation.Cores.Sega.Saturn
 		public int BufferHeight { get; private set; }
 		public int BackgroundColor { get { return unchecked((int)0xff000000); } }
 
+		public int VsyncNum
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
+
 		#endregion
 
 		#region ISyncSoundProvider

BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGX.IVideoProvider.cs

@@ -17,6 +17,10 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 
 		public int BackgroundColor { get { return unchecked((int)0xff000000); } }
 
+		public int VsyncNum { get; }
+
+		public int VsyncDen { get; }
+
 		private int[] vidbuff = new int[0];
 		private int vwidth;
 		private int vheight;

BizHawk.Emulation.Cores/Consoles/Sega/gpgx/GPGX.cs

@@ -126,9 +126,9 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 					int fpsnum = 60;
 					int fpsden = 1;
 					LibGPGX.gpgx_get_fps(ref fpsnum, ref fpsden);
-					CoreComm.VsyncNum = fpsnum;
-					CoreComm.VsyncDen = fpsden;
-					Region = CoreComm.VsyncRate > 55 ? DisplayType.NTSC : DisplayType.PAL;
+					VsyncNum = fpsnum;
+					VsyncDen = fpsden;
+					Region = VsyncNum / VsyncDen > 55 ? DisplayType.NTSC : DisplayType.PAL;
 				}
 
 				// compute state size

BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.IVideoProvider.cs

@@ -17,6 +17,10 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx64
 
 		public int BackgroundColor { get { return unchecked((int)0xff000000); } }
 
+		public int VsyncNum { get; }
+
+		public int VsyncDen { get; }
+
 		private int[] vidbuff = new int[0];
 		private int vwidth;
 		private int vheight;

BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.cs

@@ -134,9 +134,9 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx64
 					int fpsnum = 60;
 					int fpsden = 1;
 					Core.gpgx_get_fps(ref fpsnum, ref fpsden);
-					CoreComm.VsyncNum = fpsnum;
-					CoreComm.VsyncDen = fpsden;
-					Region = CoreComm.VsyncRate > 55 ? DisplayType.NTSC : DisplayType.PAL;
+					VsyncNum = fpsnum;
+					VsyncDen = fpsden;
+					Region = VsyncNum / VsyncDen > 55 ? DisplayType.NTSC : DisplayType.PAL;
 				}
 
 				// compute state size

BizHawk.Emulation.Cores/Consoles/Sony/PSP/PSP.cs

@@ -83,8 +83,6 @@ namespace BizHawk.Emulation.Cores.Sony.PSP
 			if (!good)
 				throw new Exception("PPSSPP Init failed!");
 
-			CoreComm.VsyncDen = 1;
-			CoreComm.VsyncNum = 60;
 			CoreComm.RomStatusDetails = "It puts the scythe in the chicken or it gets the abyss again!";
 
 			attachedcore = this;
@@ -173,6 +171,24 @@ namespace BizHawk.Emulation.Cores.Sony.PSP
 		public int BufferHeight { get { return screenheight; } }
 		public int BackgroundColor { get { return unchecked((int)0xff000000); } }
 
+		public int VsyncNum
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncNum;
+			}
+		}
+
+		public int VsyncDen
+		{
+			[FeatureNotImplemented]
+			get
+			{
+				return NullVideo.DefaultVsyncDen;
+			}
+		}
+
 		readonly short[] audiobuffer = new short[2048 * 2];
 		int nsampavail = 0;
 		public void GetSamplesSync(out short[] samples, out int nsamp)

BizHawk.Emulation.Cores/Consoles/Sony/PSX/Octoshock.cs

@@ -331,14 +331,14 @@ namespace BizHawk.Emulation.Cores.Sony.PSX
 			int VidClock_d = CpuClock_d * 7;
 			if (SystemRegion == OctoshockDll.eRegion.EU)
 			{
-				CoreComm.VsyncNum = VidClock_n;
-				CoreComm.VsyncDen = VidClock_d * 314 * 3406;
+				VsyncNum = VidClock_n;
+				VsyncDen = VidClock_d * 314 * 3406;
 				SystemVidStandard = OctoshockDll.eVidStandard.PAL;
 			}
 			else
 			{
-				CoreComm.VsyncNum = VidClock_n;
-				CoreComm.VsyncDen = VidClock_d * 263 * 3413;
+				VsyncNum = VidClock_n;
+				VsyncDen = VidClock_d * 263 * 3413;
 				SystemVidStandard = OctoshockDll.eVidStandard.NTSC;
 			}
 
@@ -868,6 +868,9 @@ namespace BizHawk.Emulation.Cores.Sony.PSX
 		public int BufferWidth { get; private set; }
 		public int BufferHeight { get; private set; }
 		public int BackgroundColor { get { return 0; } }
+		public int VsyncNum { get; private set; }
+		public int VsyncDen { get; private set; }
+
 		public System.Drawing.Size VideoProvider_Padding { get; private set; }
 
 		#region Debugging

BizHawk.Emulation.Cores/Consoles/WonderSwan/WonderSwan.cs

@@ -38,9 +38,6 @@ namespace BizHawk.Emulation.Cores.WonderSwan
 				if (!BizSwan.bizswan_load(Core, file, file.Length, ref ss, ref rotate))
 					throw new InvalidOperationException("bizswan_load() returned FALSE!");
 
-				CoreComm.VsyncNum = 3072000; // master CPU clock, also pixel clock
-				CoreComm.VsyncDen = (144 + 15) * (224 + 32); // 144 vislines, 15 vblank lines; 224 vispixels, 32 hblank pixels
-
 				InitISaveRam();
 
 				InitVideo(rotate);
@@ -216,6 +213,9 @@ namespace BizHawk.Emulation.Cores.WonderSwan
 		public int BufferHeight { get; private set; }
 		public int BackgroundColor { get { return unchecked((int)0xff000000); } }
 
+		public int VsyncNum => 3072000; // master CPU clock, also pixel clock
+		public int VsyncDen => (144 + 15) * (224 + 32); // 144 vislines, 15 vblank lines; 224 vispixels, 32 hblank pixels
+
 		#endregion
 	}
 }

BizHawk.Emulation.Cores/Libretro/LibretroCore.cs

@@ -128,8 +128,8 @@ namespace BizHawk.Emulation.Cores.Libretro
 			savebuff2 = new byte[savebuff.Length + 13];
 
 			// TODO: more precise
-			CoreComm.VsyncNum = (int)(10000000 * api.comm->env.retro_system_av_info.timing.fps);
-			CoreComm.VsyncDen = 10000000;
+			VsyncNum = (int)(10000000 * api.comm->env.retro_system_av_info.timing.fps);
+			VsyncDen = 10000000;
 
 			SetupResampler(api.comm->env.retro_system_av_info.timing.fps, api.comm->env.retro_system_av_info.timing.sample_rate);
 			(ServiceProvider as BasicServiceProvider).Register<ISoundProvider>(resampler);
@@ -217,6 +217,9 @@ namespace BizHawk.Emulation.Cores.Libretro
 		int IVideoProvider.BufferWidth { get { return vidWidth; } }
 		int IVideoProvider.BufferHeight { get { return vidHeight; } }
 
+		public int VsyncNum { get; private set; }
+		public int VsyncDen { get; private set; }
+
 		#region ISoundProvider
 
 		SpeexResampler resampler;

Settings.StyleCop

@@ -14,6 +14,7 @@
       <Value>savestate</Value>
       <Value>savestates</Value>
       <Value>Speex</Value>
+      <Value>vsync</Value>
     </CollectionProperty>
   </GlobalSettings>
   <Analyzers>