From 898ef6f29923fbe87e983e2f3ad2cc9c8bba09db Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Tue, 9 Sep 2025 16:46:34 +0800
Subject: [PATCH 01/22] New ResyncVocals

---
 source/funkin/game/PlayState.hx | 38 ++++++++++++++++++++++++++-------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index baad9d40d..54397b5aa 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -559,8 +559,8 @@ class PlayState extends MusicBeatState
 	@:noCompletion @:dox(hide) private var _startCountdownCalled:Bool = false;
 	@:noCompletion @:dox(hide) private var _endSongCalled:Bool = false;
 
-	@:dox(hide)
-	var __vocalSyncTimer:Float = 1;
+	@:dox(hide) var __vocalSyncTimer:Float = 0;
+	@:dox(hide) var __vocalOffsetTimer:Float = 0;
 
 	private function get_accuracy():Float {
 		if (accuracyPressedNotes <= 0) return -1;
@@ -1391,17 +1391,39 @@ class PlayState extends MusicBeatState
 			}
 		}
 		else if (FlxG.sound.music != null && (__vocalSyncTimer -= elapsed) < 0) {
-			__vocalSyncTimer = 1;
+			__vocalSyncTimer = 1 / 30;
 
 			var instTime = FlxG.sound.music.getActualTime();
-			var isOffsync:Bool = vocals.loaded && Math.abs(instTime - vocals.getActualTime()) > 100;
-			if (!isOffsync) {
-				for (strumLine in strumLines.members) {
-					if ((isOffsync = strumLine.vocals.loaded && Math.abs(instTime - strumLine.vocals.getActualTime()) > 100)) break;
+
+			var vocalsLoaded = vocals.loaded;
+			var vocalTime = vocalsLoaded ? vocals.getActualTime() : instTime;
+			var offsetTime = instTime - vocalTime;
+
+			for (i in 0...strumLines.members.length)
+			{
+				var strumLine = strumLines.members[i];
+				var strumVocals = strumLine.vocals;
+
+				if (strumVocals.loaded)
+				{
+					var strumVocalTime = strumVocals.getActualTime();
+					var currentOffset = instTime - strumVocalTime;
+
+					if (currentOffset * currentOffset > offsetTime * offsetTime)
+						offsetTime = currentOffset;
 				}
 			}
 
-			if (isOffsync) resyncVocals();
+			__vocalOffsetTimer += (offsetTime - __vocalOffsetTimer) * __vocalSyncTimer * 60 * 0.1;
+
+
+			// abs
+			if (__vocalOffsetTimer * __vocalOffsetTimer > 100) // +-10ms
+			{
+				// trace('ResyncVocals - OffsetTimer: ' + __vocalOffsetTimer);
+				__vocalOffsetTimer = 0;
+				resyncVocals();
+			}
 		}
 
 		while(events.length > 0 && events.last().time <= Conductor.songPosition)

From 60b6842cc3f8246d5892fc62851e9cb1a5ff8956 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Tue, 9 Sep 2025 17:07:29 +0800
Subject: [PATCH 02/22] Update PlayState.hx

---
 source/funkin/game/PlayState.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 54397b5aa..771c0f423 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1418,7 +1418,7 @@ class PlayState extends MusicBeatState
 
 
 			// abs
-			if (__vocalOffsetTimer * __vocalOffsetTimer > 100) // +-10ms
+			if (__vocalOffsetTimer * __vocalOffsetTimer > 64) // +-8ms
 			{
 				// trace('ResyncVocals - OffsetTimer: ' + __vocalOffsetTimer);
 				__vocalOffsetTimer = 0;

From 159225791448a7f96a8676e42144f887f5adc133 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Tue, 9 Sep 2025 18:17:12 +0800
Subject: [PATCH 03/22] Stabilize the detection mechanism.

---
 source/funkin/game/PlayState.hx | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 771c0f423..2e8ba1b03 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1391,7 +1391,8 @@ class PlayState extends MusicBeatState
 			}
 		}
 		else if (FlxG.sound.music != null && (__vocalSyncTimer -= elapsed) < 0) {
-			__vocalSyncTimer = 1 / 30;
+			__vocalSyncTimer += 1 / 30;
+			if (__vocalSyncTimer < -1 / 30) __vocalSyncTimer = -1 / 30;
 
 			var instTime = FlxG.sound.music.getActualTime();
 
@@ -1414,13 +1415,15 @@ class PlayState extends MusicBeatState
 				}
 			}
 
-			__vocalOffsetTimer += (offsetTime - __vocalOffsetTimer) * __vocalSyncTimer * 60 * 0.1;
+			__vocalOffsetTimer += (offsetTime - __vocalOffsetTimer) * (1 / 30) * 60 * 0.04;
 
+			// trace('OffsetTimer: ' + __vocalOffsetTimer + ' - Timer: ' + __vocalSyncTimer);
 
 			// abs
-			if (__vocalOffsetTimer * __vocalOffsetTimer > 64) // +-8ms
+			if (__vocalOffsetTimer * __vocalOffsetTimer > 50) // +-7.071ms
 			{
 				// trace('ResyncVocals - OffsetTimer: ' + __vocalOffsetTimer);
+				__vocalSyncTimer += 1;
 				__vocalOffsetTimer = 0;
 				resyncVocals();
 			}

From 388670c42fb9a8654a05486d8e019a98a4b3d990 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Tue, 9 Sep 2025 18:54:42 +0800
Subject: [PATCH 04/22] Update PlayState.hx

Unless any issues are discovered, this should be the final version of the modifications.
---
 source/funkin/game/PlayState.hx | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 2e8ba1b03..451a36a22 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1417,13 +1417,8 @@ class PlayState extends MusicBeatState
 
 			__vocalOffsetTimer += (offsetTime - __vocalOffsetTimer) * (1 / 30) * 60 * 0.04;
 
-			// trace('OffsetTimer: ' + __vocalOffsetTimer + ' - Timer: ' + __vocalSyncTimer);
-
-			// abs
-			if (__vocalOffsetTimer * __vocalOffsetTimer > 50) // +-7.071ms
+			if (__vocalOffsetTimer * __vocalOffsetTimer > 50) // ±7.071ms
 			{
-				// trace('ResyncVocals - OffsetTimer: ' + __vocalOffsetTimer);
-				__vocalSyncTimer += 1;
 				__vocalOffsetTimer = 0;
 				resyncVocals();
 			}

From 1c73cfa343c712d4204e9fbc373f65048c1ed76a Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Fri, 12 Sep 2025 20:39:34 +0800
Subject: [PATCH 05/22] Update PlayState.hx

Alright, to prevent cases where a sudden large audio offset could cause the smoothed value to instantly exceed the threshold and trigger readjustment, I've made further modifications. I also took the opportunity to tweak a few other things.
---
 source/funkin/game/PlayState.hx | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 451a36a22..9ae50adb8 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -561,6 +561,7 @@ class PlayState extends MusicBeatState
 
 	@:dox(hide) var __vocalSyncTimer:Float = 0;
 	@:dox(hide) var __vocalOffsetTimer:Float = 0;
+	@:dox(hide) var __vocalSmoothFactor:Float = 0.05; // (1 / 30) * 60 * 0.025
 
 	private function get_accuracy():Float {
 		if (accuracyPressedNotes <= 0) return -1;
@@ -1398,7 +1399,7 @@ class PlayState extends MusicBeatState
 
 			var vocalsLoaded = vocals.loaded;
 			var vocalTime = vocalsLoaded ? vocals.getActualTime() : instTime;
-			var offsetTime = instTime - vocalTime;
+			var maxOffset = instTime - vocalTime;
 
 			for (i in 0...strumLines.members.length)
 			{
@@ -1410,12 +1411,14 @@ class PlayState extends MusicBeatState
 					var strumVocalTime = strumVocals.getActualTime();
 					var currentOffset = instTime - strumVocalTime;
 
-					if (currentOffset * currentOffset > offsetTime * offsetTime)
-						offsetTime = currentOffset;
+					if (currentOffset * currentOffset > maxOffset * maxOffset)
+						maxOffset = currentOffset;
 				}
 			}
 
-			__vocalOffsetTimer += (offsetTime - __vocalOffsetTimer) * (1 / 30) * 60 * 0.04;
+			maxOffset = Math.min(Math.max(maxOffset, -40), 40);
+
+			__vocalOffsetTimer += (maxOffset - __vocalOffsetTimer) * __vocalSmoothFactor;
 
 			if (__vocalOffsetTimer * __vocalOffsetTimer > 50) // ±7.071ms
 			{

From 366320298ff429ae59667f5be1fd40076316636a Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Fri, 12 Sep 2025 20:50:31 +0800
Subject: [PATCH 06/22] Additional update

---
 source/funkin/game/PlayState.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 9ae50adb8..99a9a79a9 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -561,7 +561,7 @@ class PlayState extends MusicBeatState
 
 	@:dox(hide) var __vocalSyncTimer:Float = 0;
 	@:dox(hide) var __vocalOffsetTimer:Float = 0;
-	@:dox(hide) var __vocalSmoothFactor:Float = 0.05; // (1 / 30) * 60 * 0.025
+	@:dox(hide) final __vocalSmoothFactor:Float = 0.05; // (1 / 30) * 60 * 0.025
 
 	private function get_accuracy():Float {
 		if (accuracyPressedNotes <= 0) return -1;

From 431723d1f477eefe1a39647542e0040c25e14d73 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Sat, 27 Sep 2025 21:57:43 +0800
Subject: [PATCH 07/22] NEW Resync Vocals

---
 source/funkin/game/PlayState.hx | 98 ++++++++++++++++++++++-----------
 1 file changed, 67 insertions(+), 31 deletions(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 295357a3d..3976d0412 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -556,12 +556,18 @@ class PlayState extends MusicBeatState
 	 */
 	public var hitWindow:Float = Options.hitWindow; // is calculated in create(), is safeFrames in milliseconds.
 
+	/**
+		* Whether or not to use pitch correction when resyncing vocals.
+	  * Without using pitch adjustment, the audio may occasionally exhibit subtle sync drift.
+	 */
+	public var usePitchCorrection:Bool = true;
+
 	@:noCompletion @:dox(hide) private var _startCountdownCalled:Bool = false;
 	@:noCompletion @:dox(hide) private var _endSongCalled:Bool = false;
 
 	@:dox(hide) var __vocalSyncTimer:Float = 0;
 	@:dox(hide) var __vocalOffsetTimer:Float = 0;
-	@:dox(hide) final __vocalSmoothFactor:Float = 0.05; // (1 / 30) * 60 * 0.025
+	@:dox(hide) var __sounds:Array<Array<Dynamic>>;
 
 	private function get_accuracy():Float {
 		if (accuracyPressedNotes <= 0) return -1;
@@ -1237,6 +1243,29 @@ class PlayState extends MusicBeatState
 		super.onFocusLost();
 	}
 
+	/**
+	 * Call this function whenever you load new sounds
+	 * to make sure the sound list is up to date
+	 */
+	public function soundUpdate():Void
+	{
+		var sounds:Array<Array<Dynamic>> = [];
+		var idx:Int = 0;
+
+		// add main vocals
+		if (vocals.loaded) sounds[idx++] = [vocals, 0];
+
+		// also add strumline vocals
+		var sl = strumLines.members;
+		var sln = sl.length;
+		for (i in 0...sln) {
+			var sv = sl[i].vocals;
+			if (sv.loaded) sounds[idx++] = [sv, 0]; // [sound, offset]
+		}
+
+		__sounds = sounds; // update sound list
+	}
+
 	@:dox(hide)
 	function resyncVocals():Void
 	{
@@ -1399,40 +1428,47 @@ class PlayState extends MusicBeatState
 				startSong();
 			}
 		}
-		else if (FlxG.sound.music != null && (__vocalSyncTimer -= elapsed) < 0) {
-			__vocalSyncTimer += 1 / 30;
-			if (__vocalSyncTimer < -1 / 30) __vocalSyncTimer = -1 / 30;
-
-			var instTime = FlxG.sound.music.getActualTime();
-
-			var vocalsLoaded = vocals.loaded;
-			var vocalTime = vocalsLoaded ? vocals.getActualTime() : instTime;
-			var maxOffset = instTime - vocalTime;
-
-			for (i in 0...strumLines.members.length)
+		else if (FlxG.sound.music != null)
+		{
+			if ((__vocalSyncTimer -= elapsed) <= 0)
 			{
-				var strumLine = strumLines.members[i];
-				var strumVocals = strumLine.vocals;
-
-				if (strumVocals.loaded)
-				{
-					var strumVocalTime = strumVocals.getActualTime();
-					var currentOffset = instTime - strumVocalTime;
+				__vocalSyncTimer = (__vocalSyncTimer < -0.1) ? -0.1 : __vocalSyncTimer + 0.1; // max 10fps
 
-					if (currentOffset * currentOffset > maxOffset * maxOffset)
-						maxOffset = currentOffset;
+				if (__sounds != null) {
+					final soundCount = __sounds.length;
+					if (soundCount > 0)
+					{
+						final mt = FlxG.sound.music.getActualTime(); // in ms
+						final vs = usePitchCorrection ? 2500 : 225; // 15ms for no pitch correction, 50ms for pitch correction
+						final pf = 0.00025; // pitch factor
+						final sm = 0.1; // smoothing
+
+						// account for offset changes
+						var i = soundCount;
+						while (i-- > 0)
+						{
+							var sd:Array<Dynamic> = __sounds[i];
+							var s:FlxSound = sd[0];
+							final ct = s.getActualTime();
+
+							final diff = mt - ct;
+							sd[1] += (diff - sd[1]) * sm; // smooth the difference
+
+							if (usePitchCorrection) s.pitch = 1 + sd[1] * pf; // pitch adjustment
+							trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
+
+							final os = sd[1];
+							if (os * os > vs)
+							{
+								sd[1] = 0;
+								s.play(true, Conductor.songPosition); // restart sound at music position
+							}
+						}
+					}
+				} else {
+					soundUpdate();
 				}
 			}
-
-			maxOffset = Math.min(Math.max(maxOffset, -40), 40);
-
-			__vocalOffsetTimer += (maxOffset - __vocalOffsetTimer) * __vocalSmoothFactor;
-
-			if (__vocalOffsetTimer * __vocalOffsetTimer > 50) // ±7.071ms
-			{
-				__vocalOffsetTimer = 0;
-				resyncVocals();
-			}
 		}
 
 		while(events.length > 0 && events.last().time <= Conductor.songPosition)

From 131dc09c672b3a181b2baf160bbaf109903134f4 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Sat, 27 Sep 2025 22:25:10 +0800
Subject: [PATCH 08/22] Update PlayState.hx

---
 source/funkin/game/PlayState.hx | 1 -
 1 file changed, 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 3976d0412..6e01038fa 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1455,7 +1455,6 @@ class PlayState extends MusicBeatState
 							sd[1] += (diff - sd[1]) * sm; // smooth the difference
 
 							if (usePitchCorrection) s.pitch = 1 + sd[1] * pf; // pitch adjustment
-							trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
 
 							final os = sd[1];
 							if (os * os > vs)

From 9dec8798e1fcef52b137c818af2a7600db8f2aa0 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Sat, 27 Sep 2025 22:28:58 +0800
Subject: [PATCH 09/22] eee

---
 source/funkin/game/PlayState.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 6e01038fa..fd686c0c3 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1439,7 +1439,7 @@ class PlayState extends MusicBeatState
 					if (soundCount > 0)
 					{
 						final mt = FlxG.sound.music.getActualTime(); // in ms
-						final vs = usePitchCorrection ? 2500 : 225; // 15ms for no pitch correction, 50ms for pitch correction
+						final vs = usePitchCorrection ? 625 : 144; // 12ms for no pitch correction, 25ms for pitch correction
 						final pf = 0.00025; // pitch factor
 						final sm = 0.1; // smoothing
 

From 34c5c1e6cec4fa1f75f078262022eefca31efb3d Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Sat, 27 Sep 2025 22:53:26 +0800
Subject: [PATCH 10/22] Combining Two Synchronization Methods

Using time-stretching for minor corrections (subtle drift), and hard playback resets for high-latency scenarios. This approach minimizes audible pitch distortion while maintaining high-precision audio playback.
---
 source/funkin/game/PlayState.hx | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index fd686c0c3..92413101f 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1256,10 +1256,11 @@ class PlayState extends MusicBeatState
 		if (vocals.loaded) sounds[idx++] = [vocals, 0];
 
 		// also add strumline vocals
-		var sl = strumLines.members;
-		var sln = sl.length;
-		for (i in 0...sln) {
-			var sv = sl[i].vocals;
+		final sl = strumLines.members;
+		final sln = sl.length;
+		for (i in 0...sln)
+		{
+			final sv = sl[i].vocals;
 			if (sv.loaded) sounds[idx++] = [sv, 0]; // [sound, offset]
 		}
 
@@ -1269,11 +1270,17 @@ class PlayState extends MusicBeatState
 	@:dox(hide)
 	function resyncVocals():Void
 	{
-		var time = Conductor.songPosition + Conductor.songOffset;
+		final time = Conductor.songPosition + Conductor.songOffset;
 		for (strumLine in strumLines.members) strumLine.vocals.play(true, time);
 		vocals.play(true, time);
 		if (!inst.playing) inst.play(true, time);
 
+		var sounds = __sounds;
+		var sln = sounds.length;
+		for (i in 0...sln)
+			sounds[i][1] = 0;
+
+
 		gameAndCharsCall("onVocalsResync");
 	}
 
@@ -1439,7 +1446,7 @@ class PlayState extends MusicBeatState
 					if (soundCount > 0)
 					{
 						final mt = FlxG.sound.music.getActualTime(); // in ms
-						final vs = usePitchCorrection ? 625 : 144; // 12ms for no pitch correction, 25ms for pitch correction
+						final vs = usePitchCorrection ? 256 : 100; // 10ms for no pitch correction, 16ms for pitch correction
 						final pf = 0.00025; // pitch factor
 						final sm = 0.1; // smoothing
 
@@ -1462,6 +1469,7 @@ class PlayState extends MusicBeatState
 								sd[1] = 0;
 								s.play(true, Conductor.songPosition); // restart sound at music position
 							}
+							trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
 						}
 					}
 				} else {

From dcd8220b91ad5db0960627cccb162c7560f65357 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Sat, 27 Sep 2025 23:25:17 +0800
Subject: [PATCH 11/22] =?UTF-8?q?trace=20=F0=9F=98=B5=20=20=F0=9F=98=B5=20?=
 =?UTF-8?q?=20=F0=9F=98=B5?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 source/funkin/game/PlayState.hx | 1 -
 1 file changed, 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 92413101f..f65bce049 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1469,7 +1469,6 @@ class PlayState extends MusicBeatState
 								sd[1] = 0;
 								s.play(true, Conductor.songPosition); // restart sound at music position
 							}
-							trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
 						}
 					}
 				} else {

From 16c90c1023460203ed3e4fa96ee51fa21714cebe Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Sun, 28 Sep 2025 19:00:38 +0800
Subject: [PATCH 12/22] Update PlayState.hx

---
 source/funkin/game/PlayState.hx | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index f65bce049..5db3ad60c 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1435,7 +1435,7 @@ class PlayState extends MusicBeatState
 				startSong();
 			}
 		}
-		else if (FlxG.sound.music != null)
+		else if (FlxG.sound.music != null && FlxG.sound.music.playing)
 		{
 			if ((__vocalSyncTimer -= elapsed) <= 0)
 			{
@@ -1456,6 +1456,8 @@ class PlayState extends MusicBeatState
 						{
 							var sd:Array<Dynamic> = __sounds[i];
 							var s:FlxSound = sd[0];
+							if (!s.playing) continue;
+
 							final ct = s.getActualTime();
 
 							final diff = mt - ct;
@@ -1468,6 +1470,7 @@ class PlayState extends MusicBeatState
 							{
 								sd[1] = 0;
 								s.play(true, Conductor.songPosition); // restart sound at music position
+								trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
 							}
 						}
 					}

From fb3278a7cbea7b8534e9cff5b8148556f0c0e11a Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Sun, 28 Sep 2025 19:20:13 +0800
Subject: [PATCH 13/22] Update PlayState.hx

---
 source/funkin/game/PlayState.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 5db3ad60c..afa430cd0 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1470,8 +1470,8 @@ class PlayState extends MusicBeatState
 							{
 								sd[1] = 0;
 								s.play(true, Conductor.songPosition); // restart sound at music position
-								trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
 							}
+							trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
 						}
 					}
 				} else {

From 39993f364de4c3f2d835599842ea6795e99ec9d6 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Mon, 27 Oct 2025 18:09:46 +0800
Subject: [PATCH 14/22] FlxG.sound.music.getActualTime()

---
 source/funkin/game/PlayState.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 1909546bb..483203373 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1469,7 +1469,7 @@ class PlayState extends MusicBeatState
 							if (os * os > vs)
 							{
 								sd[1] = 0;
-								s.play(true, Conductor.songPosition); // restart sound at music position
+								s.play(true, mt); // restart sound at music position
 							}
 							trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
 						}

From 40ba57e0550a92a11373afe601d3af96b22199bb Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Mon, 27 Oct 2025 22:48:40 +0800
Subject: [PATCH 15/22] Update PlayState.hx

---
 source/funkin/game/PlayState.hx | 1 +
 1 file changed, 1 insertion(+)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 483203373..f2130c6a5 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1476,6 +1476,7 @@ class PlayState extends MusicBeatState
 					}
 				} else {
 					soundUpdate();
+					__vocalSyncTimer += 4.9; // next update in 5 seconds
 				}
 			}
 		}

From 443a496ce0bd1c63f100788edf8e77cbe3c0dd24 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Mon, 27 Oct 2025 22:51:44 +0800
Subject: [PATCH 16/22] 0.9

---
 source/funkin/game/PlayState.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index f2130c6a5..3c62ce24a 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1476,7 +1476,7 @@ class PlayState extends MusicBeatState
 					}
 				} else {
 					soundUpdate();
-					__vocalSyncTimer += 4.9; // next update in 5 seconds
+					__vocalSyncTimer += 0.9; // next update in 5 seconds
 				}
 			}
 		}

From 07a541637b3bd698ef3f2bda27cef9ae3a9a9105 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Tue, 28 Oct 2025 20:06:50 +0800
Subject: [PATCH 17/22] Add vocal sync interval and pitch correction flags

---
 source/funkin/backend/system/Flags.hx | 11 +++++++++++
 source/funkin/game/PlayState.hx       | 25 ++++++++++++++-----------
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/source/funkin/backend/system/Flags.hx b/source/funkin/backend/system/Flags.hx
index 1b96f7260..76821d407 100644
--- a/source/funkin/backend/system/Flags.hx
+++ b/source/funkin/backend/system/Flags.hx
@@ -169,6 +169,17 @@ class Flags {
 	public static var GITAROO_CHANCE:Float = 0.1;
 	public static var DEFAULT_MUTE_VOCALS_ON_MISS:Bool = true;
 
+	/**
+	 * Whether or not to use pitch correction when resyncing vocals.
+	 * Without using pitch adjustment, the audio may occasionally exhibit subtle sync drift.
+	 */
+	public static var VOCAL_PITCH_CORRECTION:Bool = true;
+	/**
+	 * Interval (in seconds) for vocal synchronization updates.
+	 * Smaller values mean more frequent synchronization but higher CPU usage.
+	 */
+	public static var VOCAL_SYNC_INTERVAL:Float = 0.1;
+
 	public static var DEFAULT_MAX_HEALTH:Float = 2.0;
 	public static var DEFAULT_HEALTH:Null<Float> = null;//DEFAULT_MAX_HEALTH / 2.0;
 	public static var DEFAULT_ICONBOP:Bool = true;
diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 3c62ce24a..e66d7ba8f 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -560,13 +560,15 @@ class PlayState extends MusicBeatState
 		* Whether or not to use pitch correction when resyncing vocals.
 	  * Without using pitch adjustment, the audio may occasionally exhibit subtle sync drift.
 	 */
-	public var usePitchCorrection:Bool = true;
+	public var usePitchCorrection:Bool = Flags.VOCAL_PITCH_CORRECTION;
 
 	@:noCompletion @:dox(hide) private var _startCountdownCalled:Bool = false;
 	@:noCompletion @:dox(hide) private var _endSongCalled:Bool = false;
 
-	@:dox(hide) var __vocalSyncTimer:Float = 0;
+	@:dox(hide) var __vocalIntervalMoment:Float = 0.1; // moment for interval updates
+	@:dox(hide) var __vocalSyncTimer:Float = 0.1;
 	@:dox(hide) var __vocalOffsetTimer:Float = 0;
+	@:dox(hide) var __vocalSound:Int = 0;
 	@:dox(hide) var __sounds:Array<Array<Dynamic>>;
 
 	private function get_accuracy():Float {
@@ -1265,6 +1267,7 @@ class PlayState extends MusicBeatState
 		}
 
 		__sounds = sounds; // update sound list
+		__vocalIntervalMoment = 0.05; // reset interval moment
 	}
 
 	@:dox(hide)
@@ -1439,7 +1442,7 @@ class PlayState extends MusicBeatState
 		{
 			if ((__vocalSyncTimer -= elapsed) <= 0)
 			{
-				__vocalSyncTimer = (__vocalSyncTimer < -0.1) ? -0.1 : __vocalSyncTimer + 0.1; // max 10fps
+				__vocalSyncTimer = (__vocalSyncTimer < -__vocalIntervalMoment) ? 0 : __vocalSyncTimer + __vocalIntervalMoment; // max 10fps
 
 				if (__sounds != null) {
 					final soundCount = __sounds.length;
@@ -1451,13 +1454,11 @@ class PlayState extends MusicBeatState
 						final sm = 0.1; // smoothing
 
 						// account for offset changes
-						var i = soundCount;
-						while (i-- > 0)
-						{
-							var sd:Array<Dynamic> = __sounds[i];
-							var s:FlxSound = sd[0];
-							if (!s.playing) continue;
+						final i = __vocalSound;
 
+						var sd:Array<Dynamic> = __sounds[i];
+						var s:FlxSound = sd[0];
+						if (s.playing) {
 							final ct = s.getActualTime();
 
 							final diff = mt - ct;
@@ -1471,12 +1472,14 @@ class PlayState extends MusicBeatState
 								sd[1] = 0;
 								s.play(true, mt); // restart sound at music position
 							}
-							trace('Sound ' + i + ': music=' + mt + ', sound=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch);
+							trace('Sound ' + i + ': music=' + mt + ', time=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch + ', __vocalSyncTimer=' + __vocalSyncTimer);
+
+							__vocalSound = (i + 1) % soundCount;
 						}
 					}
 				} else {
 					soundUpdate();
-					__vocalSyncTimer += 0.9; // next update in 5 seconds
+					__vocalSyncTimer = 1; // next update in 1 seconds
 				}
 			}
 		}

From 6e19d323272f91192797e4d754e9789b80b39a8b Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Tue, 28 Oct 2025 20:08:34 +0800
Subject: [PATCH 18/22] Remove  __vocalOffsetTimer

---
 source/funkin/game/PlayState.hx | 1 -
 1 file changed, 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index e66d7ba8f..d03e94b8c 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -567,7 +567,6 @@ class PlayState extends MusicBeatState
 
 	@:dox(hide) var __vocalIntervalMoment:Float = 0.1; // moment for interval updates
 	@:dox(hide) var __vocalSyncTimer:Float = 0.1;
-	@:dox(hide) var __vocalOffsetTimer:Float = 0;
 	@:dox(hide) var __vocalSound:Int = 0;
 	@:dox(hide) var __sounds:Array<Array<Dynamic>>;
 

From 99a03f27ca499ba0c167c2733b37efcbf2443bd0 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Tue, 28 Oct 2025 21:18:42 +0800
Subject: [PATCH 19/22] Improve vocal sync interval handling and docs

---
 source/funkin/backend/system/Flags.hx |  1 +
 source/funkin/game/PlayState.hx       | 17 ++++++++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/source/funkin/backend/system/Flags.hx b/source/funkin/backend/system/Flags.hx
index 76821d407..900453225 100644
--- a/source/funkin/backend/system/Flags.hx
+++ b/source/funkin/backend/system/Flags.hx
@@ -172,6 +172,7 @@ class Flags {
 	/**
 	 * Whether or not to use pitch correction when resyncing vocals.
 	 * Without using pitch adjustment, the audio may occasionally exhibit subtle sync drift.
+	 * If you just want to adjust the overall playback speed, you can try modifying FlxG.timeScale.
 	 */
 	public static var VOCAL_PITCH_CORRECTION:Bool = true;
 	/**
diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index d03e94b8c..58eae33a7 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -557,8 +557,9 @@ class PlayState extends MusicBeatState
 	public var hitWindow:Float = Options.hitWindow; // is calculated in create(), is safeFrames in milliseconds.
 
 	/**
-		* Whether or not to use pitch correction when resyncing vocals.
-	  * Without using pitch adjustment, the audio may occasionally exhibit subtle sync drift.
+	 * Whether or not to use pitch correction when resyncing vocals.
+	 * Without using pitch adjustment, the audio may occasionally exhibit subtle sync drift.
+	 * If you just want to adjust the overall playback speed, you can try modifying FlxG.timeScale.
 	 */
 	public var usePitchCorrection:Bool = Flags.VOCAL_PITCH_CORRECTION;
 
@@ -1265,8 +1266,14 @@ class PlayState extends MusicBeatState
 			if (sv.loaded) sounds[idx++] = [sv, 0]; // [sound, offset]
 		}
 
+		if (sounds.length < 1)
+		{
+			__sounds = []; // no sounds
+			return;
+		}
+
 		__sounds = sounds; // update sound list
-		__vocalIntervalMoment = 0.05; // reset interval moment
+		__vocalIntervalMoment = Flags.VOCAL_SYNC_INTERVAL / sounds.length; // reset interval moment
 	}
 
 	@:dox(hide)
@@ -1450,7 +1457,7 @@ class PlayState extends MusicBeatState
 						final mt = FlxG.sound.music.getActualTime(); // in ms
 						final vs = usePitchCorrection ? 256 : 100; // 10ms for no pitch correction, 16ms for pitch correction
 						final pf = 0.00025; // pitch factor
-						final sm = 0.1; // smoothing
+						final sm = Flags.VOCAL_SYNC_INTERVAL; // smoothing
 
 						// account for offset changes
 						final i = __vocalSound;
@@ -1471,7 +1478,7 @@ class PlayState extends MusicBeatState
 								sd[1] = 0;
 								s.play(true, mt); // restart sound at music position
 							}
-							trace('Sound ' + i + ': music=' + mt + ', time=' + ct + ', diff=' + diff + ', smoothDiff=' + sd[1] + ', pitch=' + s.pitch + ', __vocalSyncTimer=' + __vocalSyncTimer);
+							trace('Sound ' + i + ': music=' + Math.round(mt) + ' time=' + Math.round(ct) + ' diff=' + Math.round(diff * 100) / 100 + ' smoothDiff=' + Math.round(sd[1] * 100) / 100 + ' pitch=' + Math.round(s.pitch * 100000) / 100000);
 
 							__vocalSound = (i + 1) % soundCount;
 						}

From cead367a825bc71172c18075fc4790a5151115de Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Wed, 29 Oct 2025 20:30:25 +0800
Subject: [PATCH 20/22] Update Flags.hx

---
 source/funkin/backend/system/Flags.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/backend/system/Flags.hx b/source/funkin/backend/system/Flags.hx
index 900453225..3e23ec04c 100644
--- a/source/funkin/backend/system/Flags.hx
+++ b/source/funkin/backend/system/Flags.hx
@@ -179,7 +179,7 @@ class Flags {
 	 * Interval (in seconds) for vocal synchronization updates.
 	 * Smaller values mean more frequent synchronization but higher CPU usage.
 	 */
-	public static var VOCAL_SYNC_INTERVAL:Float = 0.1;
+	public static var VOCAL_SYNC_INTERVAL:Float = 0.05;
 
 	public static var DEFAULT_MAX_HEALTH:Float = 2.0;
 	public static var DEFAULT_HEALTH:Null<Float> = null;//DEFAULT_MAX_HEALTH / 2.0;

From cf0df4f010df400ba594b723e03daa91860b9c93 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Wed, 29 Oct 2025 23:25:10 +0800
Subject: [PATCH 21/22] Better Algorithm

.
---
 source/funkin/game/PlayState.hx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index 58eae33a7..dcd9a603f 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1480,7 +1480,7 @@ class PlayState extends MusicBeatState
 							}
 							trace('Sound ' + i + ': music=' + Math.round(mt) + ' time=' + Math.round(ct) + ' diff=' + Math.round(diff * 100) / 100 + ' smoothDiff=' + Math.round(sd[1] * 100) / 100 + ' pitch=' + Math.round(s.pitch * 100000) / 100000);
 
-							__vocalSound = (i + 1) % soundCount;
+							__vocalSound = i + 1 >= soundCount ? 0 : i; // next sound
 						}
 					}
 				} else {

From 1a4e47999066810d3dc864ed3d398007a3727982 Mon Sep 17 00:00:00 2001
From: HEIHUAa <112499486+HEIHUAa@users.noreply.github.com>
Date: Thu, 30 Oct 2025 14:52:06 +0800
Subject: [PATCH 22/22] variable

---
 source/funkin/game/PlayState.hx | 71 ++++++++++++++++++---------------
 1 file changed, 39 insertions(+), 32 deletions(-)

diff --git a/source/funkin/game/PlayState.hx b/source/funkin/game/PlayState.hx
index dcd9a603f..a1cc19f89 100644
--- a/source/funkin/game/PlayState.hx
+++ b/source/funkin/game/PlayState.hx
@@ -1251,29 +1251,31 @@ class PlayState extends MusicBeatState
 	 */
 	public function soundUpdate():Void
 	{
-		var sounds:Array<Array<Dynamic>> = [];
-		var idx:Int = 0;
+		var soundList:Array<Array<Dynamic>> = [];
+		var currentIndex:Int = 0;
 
 		// add main vocals
-		if (vocals.loaded) sounds[idx++] = [vocals, 0];
+		if (vocals.loaded)
+			soundList[currentIndex++] = [vocals, 0];
 
 		// also add strumline vocals
-		final sl = strumLines.members;
-		final sln = sl.length;
-		for (i in 0...sln)
+		final strumlineArray = strumLines.members;
+		final strumlineCount = strumlineArray.length;
+		for (i in 0...strumlineCount)
 		{
-			final sv = sl[i].vocals;
-			if (sv.loaded) sounds[idx++] = [sv, 0]; // [sound, offset]
+			final strumlineVocals = strumlineArray[i].vocals;
+			if (strumlineVocals.loaded)
+				soundList[currentIndex++] = [strumlineVocals, 0]; // [sound, offset]
 		}
 
-		if (sounds.length < 1)
+		if (soundList.length < 1)
 		{
 			__sounds = []; // no sounds
 			return;
 		}
 
-		__sounds = sounds; // update sound list
-		__vocalIntervalMoment = Flags.VOCAL_SYNC_INTERVAL / sounds.length; // reset interval moment
+		__sounds = soundList; // update sound list
+		__vocalIntervalMoment = Flags.VOCAL_SYNC_INTERVAL / soundList.length; // reset interval moment
 	}
 
 	@:dox(hide)
@@ -1450,37 +1452,42 @@ class PlayState extends MusicBeatState
 			{
 				__vocalSyncTimer = (__vocalSyncTimer < -__vocalIntervalMoment) ? 0 : __vocalSyncTimer + __vocalIntervalMoment; // max 10fps
 
-				if (__sounds != null) {
-					final soundCount = __sounds.length;
-					if (soundCount > 0)
+				if (__sounds != null)
+				{
+					final totalSounds = __sounds.length;
+					if (totalSounds > 0)
 					{
-						final mt = FlxG.sound.music.getActualTime(); // in ms
-						final vs = usePitchCorrection ? 256 : 100; // 10ms for no pitch correction, 16ms for pitch correction
-						final pf = 0.00025; // pitch factor
-						final sm = Flags.VOCAL_SYNC_INTERVAL; // smoothing
+						final musicTime = FlxG.sound.music.getActualTime(); // in ms
+						final varianceThreshold = usePitchCorrection ? 256 : 100; // 10ms for no pitch correction, 16ms for pitch correction
+						final pitchAdjustmentFactor = 0.00025; // pitch factor
+						final smoothingFactor = Flags.VOCAL_SYNC_INTERVAL; // smoothing
 
 						// account for offset changes
-						final i = __vocalSound;
+						final currentSoundIndex = __vocalSound;
 
-						var sd:Array<Dynamic> = __sounds[i];
-						var s:FlxSound = sd[0];
-						if (s.playing) {
-							final ct = s.getActualTime();
+						var soundData:Array<Dynamic> = __sounds[currentSoundIndex];
+						var vocalSound:FlxSound = soundData[0];
+						if (vocalSound.playing)
+						{
+							final currentVocalTime = vocalSound.getActualTime();
 
-							final diff = mt - ct;
-							sd[1] += (diff - sd[1]) * sm; // smooth the difference
+							final timeDifference = musicTime - currentVocalTime;
+							soundData[1] += (timeDifference - soundData[1]) * smoothingFactor; // smooth the difference
 
-							if (usePitchCorrection) s.pitch = 1 + sd[1] * pf; // pitch adjustment
+							if (usePitchCorrection)
+								vocalSound.pitch = 1 + soundData[1] * pitchAdjustmentFactor; // pitch adjustment
 
-							final os = sd[1];
-							if (os * os > vs)
+							final smoothedOffset = soundData[1];
+							if (smoothedOffset * smoothedOffset > varianceThreshold)
 							{
-								sd[1] = 0;
-								s.play(true, mt); // restart sound at music position
+								soundData[1] = 0;
+								vocalSound.play(true, musicTime); // restart sound at music position
 							}
-							trace('Sound ' + i + ': music=' + Math.round(mt) + ' time=' + Math.round(ct) + ' diff=' + Math.round(diff * 100) / 100 + ' smoothDiff=' + Math.round(sd[1] * 100) / 100 + ' pitch=' + Math.round(s.pitch * 100000) / 100000);
+							trace('Sound ' + currentSoundIndex + ': music=' + Math.round(musicTime) + ' time=' + Math.round(currentVocalTime) + ' diff='
+								+ Math.round(timeDifference * 100) / 100 + ' smoothDiff=' + Math.round(soundData[1] * 100) / 100 + ' pitch='
+								+ Math.round(vocalSound.pitch * 100000) / 100000);
 
-							__vocalSound = i + 1 >= soundCount ? 0 : i; // next sound
+							__vocalSound = currentSoundIndex + 1 >= totalSounds ? 0 : currentSoundIndex; // next sound
 						}
 					}
 				} else {