Stabilizza live YouTube/RTMP e fix crash rotazione mobile.

Pipeline YouTube con relay, overlay e publisher sync lato backend; fix GL pauseGlDuringRotation su Android per evitare crash in rotazione durante lo streaming Flutter.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/public/regia.js

@@ -36,6 +36,41 @@
   let pendingAction = null;
   let hls = null;
   let previewStarted = false;
+  let wasPausedPreview = false;
+
+  function hlsUrlFresh() {
+    const sep = cfg.hlsUrl.includes("?") ? "&" : "?";
+    return `${cfg.hlsUrl}${sep}_t=${Date.now()}`;
+  }
+
+  function hidePreviewPlaceholder() {
+    if (els.previewPlaceholder) els.previewPlaceholder.hidden = true;
+  }
+
+  function showPreviewPlaceholder(text) {
+    if (!els.previewPlaceholder) return;
+    els.previewPlaceholder.textContent = text;
+    els.previewPlaceholder.hidden = false;
+  }
+
+  function destroyPreview() {
+    previewStarted = false;
+    if (hls) {
+      hls.destroy();
+      hls = null;
+    }
+    if (els.preview) {
+      els.preview.removeAttribute("src");
+      els.preview.load();
+    }
+  }
+
+  function refreshPreviewForCover() {
+    if (!els.preview || !cfg.hlsUrl || cfg.streamClosed) return;
+    destroyPreview();
+    previewStarted = false;
+    startPreview();
+  }
 
   function toast(msg) {
     els.toast.textContent = msg;
@@ -169,13 +204,23 @@
       return;
     }
 
+    const paused = data.paused || data.status === "paused";
     if (data.on_air) {
-      if (!previewStarted) startPreview();
-      else if (els.preview && els.preview.readyState >= 2) hidePreviewPlaceholder();
+      if (!previewStarted) {
+        startPreview();
+      } else if (paused && !wasPausedPreview) {
+        refreshPreviewForCover();
+      } else if (paused) {
+        if (els.preview && els.preview.readyState >= 2) hidePreviewPlaceholder();
+        else els.preview?.play().catch(() => {});
+      } else if (els.preview && els.preview.readyState >= 2) {
+        hidePreviewPlaceholder();
+      }
     } else {
       destroyPreview();
       showPreviewPlaceholder("Anteprima in attesa del segnale…");
     }
+    wasPausedPreview = paused;
   }
 
   async function pollStatus() {
@@ -203,7 +248,13 @@
     const url = hlsUrlFresh();
 
     if (window.Hls && Hls.isSupported()) {
-      hls = new Hls({ lowLatencyMode: true, maxBufferLength: 8 });
+      hls = new Hls({
+        lowLatencyMode: false,
+        maxBufferLength: 30,
+        maxMaxBufferLength: 60,
+        liveSyncDurationCount: 5,
+        maxLiveSyncPlaybackRate: 1.0
+      });
       hls.loadSource(url);
       hls.attachMedia(els.preview);
       hls.on(Hls.Events.MANIFEST_PARSED, () => {
@@ -283,7 +334,42 @@
   document.getElementById("btn-share")?.addEventListener("click", () => shareLink());
   document.getElementById("btn-copy")?.addEventListener("click", () => copyLink());
 
+  function bindPreviewStallRecovery() {
+    if (!els.preview) return;
+    let stallAt = 0;
+    let lastProgressAt = Date.now();
+    let lastTime = 0;
+    const markProgress = () => {
+      const t = els.preview.currentTime;
+      if (t > lastTime + 0.05) {
+        lastTime = t;
+        lastProgressAt = Date.now();
+      }
+    };
+    els.preview.addEventListener("timeupdate", markProgress);
+    els.preview.addEventListener("playing", markProgress);
+    const nudge = (force) => {
+      if (!previewStarted || cfg.streamClosed) return;
+      const now = Date.now();
+      if (!force && now - lastProgressAt < 8000) {
+        els.preview.play().catch(() => {});
+        return;
+      }
+      if (now - stallAt < 5000) return;
+      stallAt = now;
+      lastProgressAt = now;
+      if (hls) {
+        hls.startLoad(-1);
+        els.preview.play().catch(() => {});
+      }
+    };
+    setInterval(() => {
+      if (previewStarted && !cfg.streamClosed && Date.now() - lastProgressAt > 12000) nudge(true);
+    }, 4000);
+  }
+
   bindPreviewEvents();
+  bindPreviewStallRecovery();
   if (!cfg.streamClosed && cfg.hlsUrl) {
     pollStatus();
   } else if (cfg.streamClosed) {