diff --git a/memo.txt b/memo.txt
index 30c217d1..4ce404f6 100644
--- a/memo.txt
+++ b/memo.txt
@@ -9,7 +9,8 @@ Done:
 		- init de GameComponents partagé entre serveur et client.
 		- draw on the canvas "WIN", "LOSE", "MATCHMAKING COMPLETE", ...
 		- interpolation (mis à jour progressif des mouvements de l'adversaire)
-		- traitement groupé des inputs clients toutes les x millisecondes
+		- traitement groupé des inputs clients toutes les x millisecondes	
+		  (BUG désynchronisation: revenu à un traitement immédiat en attendant)
 
 TODO:
 - mode multi-balles
diff --git a/src/client/class/InputHistory.ts b/src/client/class/InputHistory.ts
index cb7e8644..e4d3b8f1 100644
--- a/src/client/class/InputHistory.ts
+++ b/src/client/class/InputHistory.ts
@@ -1,13 +1,14 @@
 
 import * as en from "../../shared_js/enums.js"
+import * as ev from "../../shared_js/class/Event.js"
 
 class InputHistory {
 	input: en.InputEnum;
-	inputId: number;
+	id: number;
 	deltaTime: number;
-	constructor(input: en.InputEnum, inputId: number, deltaTime: number) {
-		this.input = input;
-		this.inputId = inputId;
+	constructor(inputState: ev.EventInput, deltaTime: number) {
+		this.input = inputState.input;
+		this.id = inputState.id;
 		this.deltaTime = deltaTime;
 	}
 }
diff --git a/src/client/constants.ts b/src/client/constants.ts
index 940cfce2..5a3f4d9f 100644
--- a/src/client/constants.ts
+++ b/src/client/constants.ts
@@ -8,9 +8,12 @@ export	const gridSize = Math.floor(w/500);
 
 // min interval on Firefox seems to be 15. Chrome can go lower.
 export	const handleInputIntervalMS = 15; // millisecond
+export	const sendLoopIntervalMS = 15; // millisecond
 export	const gameLoopIntervalMS = 15; // millisecond
 export	const drawLoopIntervalMS = 15; // millisecond
 
+export	const fixedDeltaTime = gameLoopIntervalMS/1000; // second
+
 export	const soundMutedFlag = true;
 export	const soundRobloxVolume = 0.3; // between 0 and 1
 export	const soundPongVolume = 0.3; // between 0 and 1
diff --git a/src/client/gameLoop.ts b/src/client/gameLoop.ts
index 1b8d212d..224e3d0e 100644
--- a/src/client/gameLoop.ts
+++ b/src/client/gameLoop.ts
@@ -1,4 +1,5 @@
 
+import * as c from "./constants.js";
 import { gc, clientInfo } from "./global.js";
 
 let actual_time: number = Date.now();
@@ -7,9 +8,12 @@ let delta_time: number;
 
 function gameLoop()
 {
-	last_time = actual_time;
+	/* last_time = actual_time;
 	actual_time = Date.now();
-	delta_time = (actual_time - last_time) / 1000;
+	delta_time = (actual_time - last_time) / 1000; */
+
+	delta_time = c.fixedDeltaTime;
+	// console.log(`delta_gameLoop: ${delta_time}`);
 
 	// interpolation
 	// console.log(`dir.y: ${clientInfo.opponent.dir.y}, pos.y: ${clientInfo.opponent.pos.y}, opponentNextPos.y: ${clientInfo.opponentNextPos.y}`);
diff --git a/src/client/handleInput.ts b/src/client/handleInput.ts
index 78b52ad2..164680e1 100644
--- a/src/client/handleInput.ts
+++ b/src/client/handleInput.ts
@@ -3,6 +3,7 @@ import { pong, gc, socket, clientInfo } from "./global.js"
 import * as ev from "../shared_js/class/Event.js"
 import * as en from "../shared_js/enums.js"
 import { InputHistory }  from "./class/InputHistory.js"
+import * as c from "./constants.js";
 
 export let gridDisplay = false;
 
@@ -10,58 +11,66 @@ let actual_time: number = Date.now();
 let last_time: number;
 let delta_time: number;
 
+const inputState: ev.EventInput = new ev.EventInput();
 const inputHistoryArr: InputHistory[] = [];
-let id = 0;
-/* idMax should be high enough to prevent duplicate "id" in "inputHistoryArr".
-In theory a little more than (1000/handleInputIntervalMS) should be enough. */
-const idMax = 999; // 999 arbitrary
+
+// test
+/* export function sendLoop()
+{
+	socket.send(JSON.stringify(inputState));
+} */
 
 function handleInput()
 {
-	last_time = actual_time;
+	/* last_time = actual_time;
 	actual_time = Date.now();
-	delta_time = (actual_time - last_time) / 1000;
+	delta_time = (actual_time - last_time) / 1000; */
+
+	delta_time = c.fixedDeltaTime;
+	// console.log(`delta_time: ${delta_time}`);
+
+	inputState.id = Date.now();
+	inputState.input = en.InputEnum.noInput;
 
 	const keys = pong.keys;
-	if (keys.length == 0) {
-		return;
-	}
-	// console.log("handleInput");
-	if (id > idMax) {
-		id = 0;
-	}
-
-	if (keys.indexOf("g") != -1)
+	if (keys.length !== 0)
 	{
-		gridDisplay = !gridDisplay;
-		pong.deleteKey("g");
+		if (keys.indexOf("g") != -1)
+		{
+			gridDisplay = !gridDisplay;
+			pong.deleteKey("g");
+		}
+		playerMovements(delta_time, keys);
 	}
 
-	playerMove(delta_time, keys);
+	socket.send(JSON.stringify(inputState));
+	// setTimeout(testInputDelay, 100);
+	inputHistoryArr.push(new InputHistory(inputState, delta_time));
+
+	// client prediction
+	if (inputState.input !== en.InputEnum.noInput) {
+		// TODO: peut-etre le mettre dans game loop ?
+		// Attention au delta time dans ce cas !
+		playerMovePrediction(delta_time, inputState.input);
+	}
 }
 
-function playerMove(delta: number, keys: string[])
+function playerMovements(delta: number, keys: string[])
 {
-	if (keys.indexOf("w") !== -1 || keys.indexOf("ArrowUp".toLowerCase()) !== -1) {
+	if (keys.indexOf("w") !== -1 || keys.indexOf("ArrowUp".toLowerCase()) !== -1)
+	{
 		if (keys.indexOf("s") === -1 && keys.indexOf("ArrowDown".toLowerCase()) === -1) {
-			const input = new ev.EventInput(en.InputEnum.up, ++id);
-			inputHistoryArr.push(new InputHistory(input.input, input.inputId, delta));
-			socket.send(JSON.stringify(input));
-			playerMovePrediction(delta, input.input); // client prediction
+			inputState.input = en.InputEnum.up;
 		}
 	}
 	else if (keys.indexOf("s") !== -1 || keys.indexOf("ArrowDown".toLowerCase()) !== -1) {
-		const input = new ev.EventInput(en.InputEnum.down, ++id);
-		inputHistoryArr.push(new InputHistory(input.input, input.inputId, delta));
-		socket.send(JSON.stringify(input));
-		playerMovePrediction(delta, input.input); // client prediction
+		inputState.input = en.InputEnum.down;
 	}
 }
 
-function testInputDelay(input: ev.EventInput) {
-	socket.send(JSON.stringify(input));
+function testInputDelay() {
+	socket.send(JSON.stringify(inputState));
 }
-// setTimeout(testInputDelay, 100, input);
 
 
 function playerMovePrediction(delta: number, input: en.InputEnum)
@@ -81,16 +90,20 @@ function repeatInput(lastInputId: number)
 {
 	// server reconciliation
 	let i = inputHistoryArr.findIndex((value: InputHistory) => {
-		if (value.inputId === lastInputId) {
+		if (value.id === lastInputId) {
 			return true;
 		}
 		return false;
 	});
 
+	// console.log(`inputHistory total: ${inputHistoryArr.length}` );
 	inputHistoryArr.splice(0, i+1);
+	// console.log(`inputHistory left: ${inputHistoryArr.length}` );
 	
 	inputHistoryArr.forEach((value: InputHistory) => {
-		playerMovePrediction(value.deltaTime, value.input);
+		if (value.input !== en.InputEnum.noInput) {
+			playerMovePrediction(value.deltaTime, value.input);
+		}
 	});
 }
 
diff --git a/src/client/pong.ts b/src/client/pong.ts
index a6606704..05be7494 100644
--- a/src/client/pong.ts
+++ b/src/client/pong.ts
@@ -3,6 +3,7 @@ import * as c from "./constants.js"
 import { GameArea } from "./class/GameArea.js";
 import { GameComponentsClient } from "./class/GameComponentsClient.js";
 import { handleInput } from "./handleInput.js";
+// import { sendLoop } from "./handleInput.js";
 import { gameLoop } from "./gameLoop.js"
 import { drawLoop } from "./draw.js";
 import { countdown } from "./utils.js";
@@ -54,8 +55,9 @@ function resumeGame()
 		pong.deleteKey(e.key);
 	});
 	pong.handleInputInterval = window.setInterval(handleInput, c.handleInputIntervalMS);
+	// pong.handleInputInterval = window.setInterval(sendLoop, c.sendLoopIntervalMS);
 	pong.gameLoopInterval = window.setInterval(gameLoop, c.gameLoopIntervalMS);
-	pong.gameLoopInterval = window.setInterval(drawLoop, c.drawLoopIntervalMS);
+	pong.drawLoopInterval = window.setInterval(drawLoop, c.drawLoopIntervalMS);
 }
 
 
diff --git a/src/client/ws.ts b/src/client/ws.ts
index ae4cc2e3..e80c640f 100644
--- a/src/client/ws.ts
+++ b/src/client/ws.ts
@@ -93,6 +93,9 @@ function gameUpdate(data: ev.EventGameUpdate)
 	gc.ball.pos.assign(data.ball.x, data.ball.y);
 	gc.ball.dir.assign(data.ball.dirX, data.ball.dirY);
 	gc.ball.speed = data.ball.speed;
+
+	const predictionPos = new VectorInteger(clientInfo.racket.pos.x, clientInfo.racket.pos.y); // debug
+
 	if (clientInfo.side === en.PlayerSide.left) {
 		clientInfo.racket.pos.assign(clientInfo.racket.pos.x, data.playerLeft.y);
 	}
@@ -120,11 +123,23 @@ function gameUpdate(data: ev.EventGameUpdate)
 
 	// server reconciliation
 	repeatInput(data.lastInputId);
+
+	// debug
+	if (clientInfo.racket.pos.y > predictionPos.y + 1
+	||  clientInfo.racket.pos.y < predictionPos.y - 1)
+	{
+		console.log(
+			`Reconciliation error:
+			server y:         ${data.playerLeft.y}
+			reconciliation y: ${clientInfo.racket.pos.y}
+			prediction y:     ${predictionPos.y}`
+			);
+	}
 }
 
 function scoreUpdate(data: ev.EventScoreUpdate)
 {
-	console.log("scoreUpdate");
+	// console.log("scoreUpdate");
 	if (clientInfo.side === en.PlayerSide.left && data.scoreRight > gc.scoreRight.value) {
 		soundRoblox.play();
 	}
diff --git a/src/server/class/Client.ts b/src/server/class/Client.ts
index ac9a8983..c1678848 100644
--- a/src/server/class/Client.ts
+++ b/src/server/class/Client.ts
@@ -10,7 +10,7 @@ class Client {
 	isAlive: boolean = true;
 	gameSession: GameSession;
 
-	inputBuffer: ev.EventInput;
+	inputBuffer: ev.EventInput = new ev.EventInput();
 	lastInputId: number = 0;
 	
 	constructor(socket: WebSocket, id: string) {
diff --git a/src/server/class/GameSession.ts b/src/server/class/GameSession.ts
index 866872d9..dc72e507 100644
--- a/src/server/class/GameSession.ts
+++ b/src/server/class/GameSession.ts
@@ -39,7 +39,7 @@ class GameSession {
 		});
 
 		s.actual_time = Date.now();
-		s.gameLoopInterval = setInterval(s._gameLoop, c.gameLoopIntervalMS, s);
+		s.gameLoopInterval = setInterval(s._gameLoop, c.serverGameLoopIntervalMS, s);
 		s.clientsUpdateInterval = setInterval(s._clientsUpdate, c.clientsUpdateIntervalMS, s);
 	}
 	pause(s: GameSession) {
@@ -50,7 +50,11 @@ class GameSession {
 		clearInterval(s.gameLoopInterval);
 		clearInterval(s.clientsUpdateInterval);
 	}
+	instantInputDebug(client: ClientPlayer) {
+		this._handleInput(c.fixedDeltaTime, client);
+	}
 	private _handleInput(delta: number, client: ClientPlayer) {
+		// if (client.inputBuffer === null) {return;}
 		const gc = this.components;
 		const input = client.inputBuffer.input;
 
@@ -60,10 +64,13 @@ class GameSession {
 		else if (input === en.InputEnum.down) {
 			client.racket.dir.y = 1;
 		}
-		client.racket.moveAndCollide(delta, [gc.wallTop, gc.wallBottom]);
+		
+		if (input !== en.InputEnum.noInput) {
+			client.racket.moveAndCollide(delta, [gc.wallTop, gc.wallBottom]);
+		}
 
-		client.lastInputId = client.inputBuffer.inputId;
-		client.inputBuffer = null;
+		client.lastInputId = client.inputBuffer.id;
+		// client.inputBuffer = null;
 	}
 	private _gameLoop(s: GameSession) {
 		/* s.last_time = s.actual_time;
@@ -71,11 +78,10 @@ class GameSession {
 		s.delta_time = (s.actual_time - s.last_time) / 1000; */
 		s.delta_time = c.fixedDeltaTime;
 
-		s.playersMap.forEach( (client) => {
-			if (client.inputBuffer) {
-				s._handleInput(s.delta_time, client);
-			}
-		});
+		// WIP, replaced by instantInputDebug() to prevent desynchro
+		/* s.playersMap.forEach( (client) => {
+			s._handleInput(s.delta_time, client);
+		}); */
 
 		const gc = s.components;
 		if (gc.ballInPlay)
diff --git a/src/server/constants.ts b/src/server/constants.ts
index 761622fb..bd5f8e9e 100644
--- a/src/server/constants.ts
+++ b/src/server/constants.ts
@@ -2,8 +2,8 @@
 export * from "../shared_js/constants.js"
 
 // 15ms == 1000/66.666
-export	const gameLoopIntervalMS = 15; // millisecond
-export	const fixedDeltaTime = gameLoopIntervalMS/1000; // second
+export	const serverGameLoopIntervalMS = 15; // millisecond
+export	const fixedDeltaTime = serverGameLoopIntervalMS/1000; // second
 
 // 33.333ms == 1000/30
 export	const clientsUpdateIntervalMS = 1000/30; // millisecond
diff --git a/src/server/wsServer.ts b/src/server/wsServer.ts
index f8138c39..51c33c9b 100644
--- a/src/server/wsServer.ts
+++ b/src/server/wsServer.ts
@@ -58,8 +58,8 @@ function clientAnnounceListener(this: WebSocket, data: string)
 	try {
 		const msg : ev.ClientAnnounce = JSON.parse(data);
 		if (msg.type === en.EventTypes.clientAnnounce) {
-			// TODO: reconnection with msg.id ?
-			// TODO: spectator/player distinction with msg.type ?
+			// TODO: reconnection with msg.clientId ?
+			// TODO: spectator/player distinction with msg.role ?
 
 			this.send(JSON.stringify( new ev.EventAssignId(this.id) ));
 			this.send(JSON.stringify( new ev.ServerEvent(en.EventTypes.matchmakingInProgress) ));
@@ -152,6 +152,7 @@ export function clientInputListener(this: WebSocket, data: string)
 		if (input.type === en.EventTypes.clientInput) {
 			const client = clientsMap.get(this.id) as ClientPlayer;
 			client.inputBuffer = input;
+			client.gameSession.instantInputDebug(client); // wip
 		}
 		else {
 			console.log("Invalid clientInput");
diff --git a/src/shared_js/class/Event.ts b/src/shared_js/class/Event.ts
index d35d1f0d..14b86ff3 100644
--- a/src/shared_js/class/Event.ts
+++ b/src/shared_js/class/Event.ts
@@ -66,7 +66,7 @@ class EventMatchEnd extends ServerEvent {
 
 /* From Client */
 class ClientEvent {
-	type: en.EventTypes;
+	type: en.EventTypes; // readonly ?
 	constructor(type: en.EventTypes = 0) {
 		this.type = type;
 	}
@@ -74,21 +74,21 @@ class ClientEvent {
 
 class ClientAnnounce extends ClientEvent {
 	role: en.ClientRole;
-	id: string;
-	constructor(role: en.ClientRole, id: string = "") {
+	clientId: string;
+	constructor(role: en.ClientRole, clientId: string = "") {
 		super(en.EventTypes.clientAnnounce);
 		this.role = role;
-		this.id = id;
+		this.clientId = clientId;
 	}
 }
 
 class EventInput extends ClientEvent {
 	input: en.InputEnum;
-	inputId: number;
-	constructor(input: en.InputEnum = 0, inputId: number = 0) {
+	id: number;
+	constructor(input: en.InputEnum = en.InputEnum.noInput, id: number = 0) {
 		super(en.EventTypes.clientInput);
 		this.input = input;
-		this.inputId = inputId;
+		this.id = id;
 	}
 }
 
diff --git a/src/shared_js/class/Rectangle.ts b/src/shared_js/class/Rectangle.ts
index 639dbd75..8b9e1260 100644
--- a/src/shared_js/class/Rectangle.ts
+++ b/src/shared_js/class/Rectangle.ts
@@ -44,10 +44,15 @@ class MovingRectangle extends Rectangle implements Moving {
 	}
 	move(delta: number) { // Math.floor WIP until VectorInteger debug
 		// console.log(`delta: ${delta}, speed: ${this.speed}, speed*delta: ${this.speed * delta}`);
-		this.pos.x += Math.floor(this.dir.x * this.speed * delta);
-		this.pos.y += Math.floor(this.dir.y * this.speed * delta);
+		// this.pos.x += Math.floor(this.dir.x * this.speed * delta);
+		// this.pos.y += Math.floor(this.dir.y * this.speed * delta);
+		this.pos.x += this.dir.x * this.speed * delta;
+		this.pos.y += this.dir.y * this.speed * delta;
 	}
 	moveAndCollide(delta: number, colliderArr: Rectangle[]) {
+		this._moveAndCollideAlgo(delta, colliderArr);
+	}
+	protected _moveAndCollideAlgo(delta: number, colliderArr: Rectangle[]) {
 		let oldPos = new VectorInteger(this.pos.x, this.pos.y);
 		this.move(delta);
 		if (colliderArr.some(this.collision, this)) {
@@ -60,6 +65,11 @@ class Racket extends MovingRectangle {
 	constructor(pos: VectorInteger, width: number, height: number, baseSpeed: number) {
 		super(pos, width, height, baseSpeed);
 	}
+	moveAndCollide(delta: number, colliderArr: Rectangle[]) {
+		// let oldPos = new VectorInteger(this.pos.x, this.pos.y); // debug
+		this._moveAndCollideAlgo(delta, colliderArr);
+		// console.log(`y change: ${this.pos.y - oldPos.y}`);
+	}
 }
 
 class Ball extends MovingRectangle {
diff --git a/src/shared_js/enums.ts b/src/shared_js/enums.ts
index 1acf2219..cc8ec311 100644
--- a/src/shared_js/enums.ts
+++ b/src/shared_js/enums.ts
@@ -22,8 +22,9 @@ enum EventTypes {
 }
 
 enum InputEnum {
+	noInput = 0,
 	up = 1,
-	down
+	down,
 }
 
 enum PlayerSide {