fix: suppress ghost seek events on tab re-focus (Firefox tab throttling)

README.md

@@ -8,7 +8,7 @@
   <a href="https://chromewebstore.google.com/detail/koalasync/obbnmkmlaaddodakcbdljknjpagklifc"><img src="https://img.shields.io/badge/Chrome-Download-blue?logo=googlechrome&logoColor=white" alt="Chrome Extension"></a>
 </p>
 
-<p align="center"><i>KoalaSync is a lightweight Browser Extension and Relay Server for synchronized video playback across any website—YouTube, Twitch, Netflix, and custom HTML5 players. Built with a focus on <b>Data Sovereignty</b> and <b>Performance</b>.</i></p>
+<p align="center"><i>KoalaSync is a lightweight Browser Extension and Relay Server for synchronized video playback on almost any website with a video element—YouTube, Twitch, Netflix, Emby, Jellyfin, and beyond. Built with a focus on <b>Data Sovereignty</b> and <b>Performance</b>.</i></p>
 
 ### 🌟 Why KoalaSync?
 

extension/content.js

@@ -417,6 +417,10 @@
             }
             return;
         }
+
+        // Suppress only SEEK during visibility grace period (tab re-focus ghost jump).
+        // Play/Pause pass through — user may want to immediately pause after tabbing back.
+        if (Date.now() < visibilityGraceUntil && action === EVENTS.SEEK) return;
         
         chrome.runtime.sendMessage({
             type: 'CONTENT_EVENT',
@@ -433,6 +437,38 @@
         scheduleProactiveHeartbeat();
     }
 
+    // --- Tab Visibility Handling ---
+    // Browsers (especially Firefox) aggressively throttle background tabs.
+    // When the user returns to a video tab, the video element may have lost
+    // time-sync and fires spurious seek events as it recovers (jumping back).
+    // We suppress only SEEK for a short grace period after tab re-focus.
+    // Play/Pause are NOT suppressed — the user may legitimately want to
+    // pause immediately after switching back.
+    let pageVisible = !document.hidden;
+    let visibilityGraceUntil = 0;
+    const VISIBILITY_GRACE_MS = 1000;
+
+    document.addEventListener('visibilitychange', () => {
+        if (document.hidden) {
+            pageVisible = false;
+        } else if (!pageVisible) {
+            pageVisible = true;
+            visibilityGraceUntil = Date.now() + VISIBILITY_GRACE_MS;
+            reportLog(`Tab re-focused — suppressing seeks for ${VISIBILITY_GRACE_MS / 1000}s to prevent ghost relay`, 'warn');
+        }
+    });
+
+    // Reset on page hide/show (bfcache, tab discard)
+    window.addEventListener('pagehide', () => { pageVisible = false; });
+    window.addEventListener('pageshow', (event) => {
+        // event.persisted is true ONLY when restored from bfcache, not on initial load
+        if (event.persisted && !pageVisible) {
+            pageVisible = true;
+            visibilityGraceUntil = Date.now() + VISIBILITY_GRACE_MS;
+            reportLog(`Page restored from cache — suppressing seeks for ${VISIBILITY_GRACE_MS / 1000}s`, 'warn');
+        }
+    });
+
     const handlePlay = () => reportEvent(EVENTS.PLAY);
     const handlePause = () => reportEvent(EVENTS.PAUSE);
 
@@ -444,7 +480,7 @@
         const current = video.currentTime;
         if (!Number.isFinite(current)) return;
 
-        // Step 1: Check expectedEvents (programmatic seek suppression)
+        // Step 1: Check expectedEvents (programmatic seek from remote peer — ALWAYS process)
         if (expectedEvents.has('seek')) {
             expectedEvents.delete('seek');
             if (expectedTimeouts['seek']) {
@@ -452,20 +488,22 @@
                 delete expectedTimeouts['seek'];
             }
             lastReportedSeekTime = current;
-            // No log — this is routine programmatic behavior (Force Sync, lobby, peer command)
             return;
         }
 
+        // Step 2: Suppress during visibility grace period (tab re-focus ghost events)
+        if (Date.now() < visibilityGraceUntil) return;
+
         const delta = lastReportedSeekTime !== null ? Math.abs(current - lastReportedSeekTime) : null;
         const deltaStr = delta !== null ? `Δ${delta.toFixed(2)}s` : 'Δ?';
 
-        // Step 2: Delta check — skip micro-seeks (buffering, chapter markers, etc.)
+        // Step 3: Delta check — skip micro-seeks (buffering, chapter markers, etc.)
         if (lastReportedSeekTime !== null && delta < MIN_SEEK_DELTA) {
             reportLog(`[Seek] Filtered (${deltaStr} < ${MIN_SEEK_DELTA}s threshold) @ ${current.toFixed(2)}s — not relayed`, 'warn');
             return;
         }
 
-        // Step 3: Debounce rapid consecutive seeks (e.g. scrubbing)
+        // Step 4: Debounce rapid consecutive seeks (e.g. scrubbing)
         // — wait 800ms for the user to settle before relaying
         if (seekDebounceTimer) clearTimeout(seekDebounceTimer);
         seekDebounceTimer = setTimeout(() => {

extension/manifest.base.json

@@ -1,8 +1,8 @@
 {
   "manifest_version": 3,
   "name": "KoalaSync",
-  "version": "1.8.5",
-  "description": "Watch party extension to synchronize video playback on YouTube, Twitch, Netflix, and HTML5 sites in real-time with friends.",
+  "version": "1.8.6",
+  "description": "Watch party extension to synchronize video playback on YouTube, Twitch, Netflix, Emby, Jellyfin, and any HTML5 site in real-time with friends.",
   "permissions": [
     "storage",
     "tabs",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "koalasync",
-  "version": "1.8.6",
+  "version": "1.8.7",
   "description": "KoalaSync Build Scripts",
   "private": true,
   "scripts": {

shared/constants.js

@@ -7,7 +7,7 @@
  */
 
 export const PROTOCOL_VERSION = "1.0.0";
-export const APP_VERSION = "1.3.1";
+export const APP_VERSION = "1.8.6";
 
 export const OFFICIAL_SERVER_URL = 'wss://syncserver.koalastuff.net';
 export const OFFICIAL_LANDING_PAGE_URL = 'https://sync.koalastuff.net';

website/index.html

@@ -3,15 +3,18 @@
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>KoalaSync | Real-time Video Synchronization for Friends</title>
-    <meta name="description" content="Watch YouTube, Twitch, and HTML5 videos in sync with friends. KoalaSync is a privacy-first, open-source browser extension for Chrome and Firefox.">
+    <title>KoalaSync | Sync Netflix, Emby, Jellyfin & Any Video with Friends – Browser Extension</title>
+    <meta name="description" content="Watch Netflix, Emby, Jellyfin, YouTube, Twitch and any HTML5 video in perfect sync with friends. KoalaSync is a privacy-first, open-source browser extension for Chrome and Firefox. Works on almost any site with a video element.">
     
     <link rel="stylesheet" href="style.css">
     <link rel="icon" type="image/png" href="assets/logo.png">
-    <meta property="og:title" content="KoalaSync | Sync your videos">
-    <meta property="og:description" content="Watch together, stay in sync. Privacy-first video synchronization.">
+    <link rel="canonical" href="https://sync.koalastuff.net/">
+    <meta name="robots" content="index, follow">
+    <meta property="og:title" content="KoalaSync | Sync Netflix, Emby, Jellyfin & Any Video with Friends">
+    <meta property="og:description" content="Watch Netflix, Emby, Jellyfin, YouTube, Twitch and any HTML5 video in perfect sync. Privacy-first, open-source browser extension for Chrome & Firefox.">
     <meta property="og:image" content="https://sync.koalastuff.net/assets/logo.png">
     <meta property="og:type" content="website">
+    <meta property="og:url" content="https://sync.koalastuff.net/">
 
     <script src="lang-init.js"></script>
 </head>

website/robots.txt

@@ -1,4 +1,6 @@
+# KoalaSync Website — Allow all crawlers, full indexing
 User-agent: *
 Allow: /
 
+# Sitemap for search engines
 Sitemap: https://sync.koalastuff.net/sitemap.xml

website/version.json

@@ -1,4 +1,4 @@
 {
-  "version": "1.8.5",
-  "date": "2026-05-25T21:56:58Z"
+  "version": "1.8.6",
+  "date": "2026-05-25T23:07:55Z"
 }