From 1f313b42c83f7538984594a5642cac3adfa0bdba Mon Sep 17 00:00:00 2001
From: nattthebear <goyuken@gmail.com>
Date: Tue, 20 Oct 2020 18:27:28 -0400
Subject: [PATCH] Change NES ideal framerates

These are used for realtime and recorded AV output.  They match closely what the core actually does (not idealized values about what the NES framerate ""should"" be.)

Fixes #2460
---
 .../Consoles/Nintendo/NES/NES.Core.cs            | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
index 49d78232bd..147965ed4f 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
@@ -27,7 +27,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		public bool _irq_apu; //various irq signals that get merged to the cpu irq pin
 		
-		/// <summary>clock speed of the main cpu in hz</summary>
+		/// <summary>
+		/// Clock speed of the main cpu in hz.  Used to time audio synthesis, which runs off the cpu clock.
+		/// </summary>
 		public int cpuclockrate { get; private set; }
 
 		//user configuration 
@@ -175,9 +177,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				case DisplayType.PAL:
 					apu = new APU(this, apu, true);
 					ppu.region = PPU.Region.PAL;
-					VsyncNum = 50;
-					VsyncDen = 1;
 					cpuclockrate = 1662607;
+					VsyncNum = cpuclockrate * 2;
+					VsyncDen = 66495;
 					cpu_sequence = cpu_sequence_PAL;
 					_display_type = DisplayType.PAL;
 					ClockRate = 5320342.5;
@@ -185,9 +187,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				case DisplayType.NTSC:
 					apu = new APU(this, apu, false);
 					ppu.region = PPU.Region.NTSC;
-					VsyncNum = 39375000;
-					VsyncDen = 655171;
 					cpuclockrate = 1789773;
+					VsyncNum = cpuclockrate * 2;
+					VsyncDen = 59561;
 					cpu_sequence = cpu_sequence_NTSC;
 					ClockRate = 5369318.1818181818181818181818182;
 					break;
@@ -195,9 +197,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				case DisplayType.Dendy:
 					apu = new APU(this, apu, false);
 					ppu.region = PPU.Region.Dendy;
-					VsyncNum = 50;
-					VsyncDen = 1;
 					cpuclockrate = 1773448;
+					VsyncNum = cpuclockrate;
+					VsyncDen = 35464;
 					cpu_sequence = cpu_sequence_NTSC;
 					_display_type = DisplayType.Dendy;
 					ClockRate = 5320342.5;