From 98b3d8d33583a3479eab28baf1377ccfac318eeb Mon Sep 17 00:00:00 2001
From: zeromus <zeromus@users.noreply.github.com>
Date: Mon, 15 Jun 2020 15:10:20 -0400
Subject: [PATCH] change PSX framerates to follow mednafen instead of nocash
 (fixes #2138)

---
 .../movie/PlatformFrameRates.cs               | 17 +++----
 .../Consoles/Sony/PSX/Octoshock.cs            | 49 ++++++++++++++-----
 2 files changed, 43 insertions(+), 23 deletions(-)

diff --git a/src/BizHawk.Client.Common/movie/PlatformFrameRates.cs b/src/BizHawk.Client.Common/movie/PlatformFrameRates.cs
index 66c7ad19dd..1fdefe1324 100644
--- a/src/BizHawk.Client.Common/movie/PlatformFrameRates.cs
+++ b/src/BizHawk.Client.Common/movie/PlatformFrameRates.cs
@@ -46,6 +46,7 @@ namespace BizHawk.Client.Common
 			// while the number of scanlines per frame is software controlled and variable, we
 			// enforce exactly 262 (NTSC) 312 (PAL) per reference time frame
 			["A26"] = 315000000.0 / 88.0 / 262.0 / 228.0, // 59.922751013550531429197560173856
+
 			// this pal clock ref is exact
 			["A26_PAL"] = 3546895.0 / 312.0 / 228.0, // 49.860759671614934772829509671615
 
@@ -53,8 +54,11 @@ namespace BizHawk.Client.Common
 			["Coleco"] = 59.9227510135505,
 
 			// according to http://problemkaputt.de/psx-spx.htm
-			["PSX"] = 44100.0 * 768 * 11 / 7 / 263 / 3413, // 59.292862562
-			["PSX_PAL"] = 44100.0 * 768 * 11 / 7 / 314 / 3406, // 49.7645593576
+			//["PSX"] = 44100.0 * 768 * 11 / 7 / 263 / 3413, // 59.292862562
+			//["PSX_PAL"] = 44100.0 * 768 * 11 / 7 / 314 / 3406, // 49.7645593576
+			// according to https://github.com/TASVideos/mednafen/blob/740d63996fc7cebffd39ee253a29ee434965db21/src/psx/gpu.cpp
+			["PSX"] = 502813668.0 / 8388608, //59.940060138702392578125
+			["PSX_PAL"] = 419432765.0 / 8388608, //50.00028192996978759765625
 
 			["C64_PAL"] = PALCarrier * 2 / 9 / 312 / 63,
 			["C64_NTSC"] = NTSCCarrier * 2 / 7 / 263 / 65,
@@ -64,15 +68,6 @@ namespace BizHawk.Client.Common
 
 			["ZXSpectrum_PAL"] = 50.080128205,
 			["AmstradCPC_PAL"] = 50.08012820512821,
-
-			// according to ryphecha, using
-			// clocks[2] = { 53.693182e06, 53.203425e06 }; //ntsc console, pal console
-			// lpf[2][2] = { { 263, 262.5 }, { 314, 312.5 } }; //ntsc,pal; non-interlaced, interlaced
-			// cpl[2] = { 3412.5, 3405 }; //ntsc mode, pal mode
-			// PAL PS1: 0, PAL Mode: 0, Interlaced: 0 --- 59.826106 (53.693182e06/(263*3412.5))
-			// PAL PS1: 0, PAL Mode: 0, Interlaced: 1 --- 59.940060 (53.693182e06/(262.5*3412.5))
-			// PAL PS1: 1, PAL Mode: 1, Interlaced: 0 --- 49.761427 (53.203425e06/(314*3405))
-			// PAL PS1: 1, PAL Mode: 1, Interlaced: 1 --- 50.000282(53.203425e06/(312.5*3405))
 		};
 
 		public double this[string systemId, bool pal]
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Sony/PSX/Octoshock.cs b/src/BizHawk.Emulation.Cores/Consoles/Sony/PSX/Octoshock.cs
index 2fcea21ec9..aef100eb59 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Sony/PSX/Octoshock.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Sony/PSX/Octoshock.cs
@@ -102,22 +102,47 @@ namespace BizHawk.Emulation.Cores.Sony.PSX
 				SystemRegion = discInfo.region;
 			}
 
-			//see http://problemkaputt.de/psx-spx.htm
-			int CpuClock_n = 44100 * 768;
-			int CpuClock_d = 1;
-			int VidClock_n = CpuClock_n * 11;
-			int VidClock_d = CpuClock_d * 7;
-			if (SystemRegion == OctoshockDll.eRegion.EU)
+			bool use_nocash_specs = false;
+
+			if (use_nocash_specs)
 			{
-				VsyncNumerator = VidClock_n;
-				VsyncDenominator = VidClock_d * 314 * 3406;
-				SystemVidStandard = OctoshockDll.eVidStandard.PAL;
+				//see http://problemkaputt.de/psx-spx.htm
+				int CpuClock_n = 44100 * 768;
+				int CpuClock_d = 1;
+				int VidClock_n = CpuClock_n * 11;
+				int VidClock_d = CpuClock_d * 7;
+				if (SystemRegion == OctoshockDll.eRegion.EU)
+				{
+					VsyncNumerator = VidClock_n;
+					VsyncDenominator = VidClock_d * 314 * 3406;
+					SystemVidStandard = OctoshockDll.eVidStandard.PAL;
+				}
+				else
+				{
+					VsyncNumerator = VidClock_n;
+					VsyncDenominator = VidClock_d * 263 * 3413;
+					SystemVidStandard = OctoshockDll.eVidStandard.NTSC;
+				}
 			}
 			else
 			{
-				VsyncNumerator = VidClock_n;
-				VsyncDenominator = VidClock_d * 263 * 3413;
-				SystemVidStandard = OctoshockDll.eVidStandard.NTSC;
+				//use mednafen specs
+				if (SystemRegion == OctoshockDll.eRegion.EU)
+				{
+					//https://github.com/TASVideos/mednafen/blob/740d63996fc7cebffd39ee253a29ee434965db21/src/psx/gpu.cpp#L175
+					// -> 838865530 / 65536 / 256 -> reduced
+					VsyncNumerator = 419432765;
+					VsyncDenominator = 8388608;
+					SystemVidStandard = OctoshockDll.eVidStandard.PAL;
+				}
+				else
+				{
+					//https://github.com/TASVideos/mednafen/blob/740d63996fc7cebffd39ee253a29ee434965db21/src/psx/gpu.cpp#L183
+					//-> 1005627336 / 65536 / 256 -> reduced
+					VsyncNumerator = 502813668;
+					VsyncDenominator = 8388608;
+					SystemVidStandard = OctoshockDll.eVidStandard.NTSC;
+				}
 			}
 
 			//TODO - known bad firmwares are a no-go. we should refuse to boot them. (that's the mednafen policy)