fix: reduce hls playback churn

internal/server/observability.go

@@ -44,6 +44,9 @@ func RequestLogger(metrics *observability.Metrics) gin.HandlerFunc {
 		if len(privateErrors) > 0 {
 			logErr = privateErrors.Last().Err
 		}
+		if route == "/watch/proxy/stream" && status < 400 && len(privateErrors) == 0 {
+			return
+		}
 		if route != path {
 			fields["route"] = route
 		}

internal/server/server_test.go

@@ -95,6 +95,60 @@ func TestRequestLoggerUsesMatchedRoute(t *testing.T) {
 	}
 }
 
+func TestRequestLoggerSkipsSuccessfulStreamProxy(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	var logs bytes.Buffer
+	previousOutput := log.Writer()
+	log.SetOutput(&logs)
+	defer log.SetOutput(previousOutput)
+
+	router := gin.New()
+	router.Use(RequestContextMiddleware())
+	router.Use(RequestLogger(observability.NewMetrics()))
+	router.GET("/watch/proxy/stream", func(c *gin.Context) {
+		c.String(http.StatusOK, "segment")
+	})
+
+	req := httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/watch/proxy/stream?token=abc", nil)
+	rec := httptest.NewRecorder()
+	router.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
+	}
+	if got := logs.String(); got != "" {
+		t.Fatalf("expected no successful stream proxy log, got %s", got)
+	}
+}
+
+func TestRequestLoggerLogsFailedStreamProxy(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	var logs bytes.Buffer
+	previousOutput := log.Writer()
+	log.SetOutput(&logs)
+	defer log.SetOutput(previousOutput)
+
+	router := gin.New()
+	router.Use(RequestContextMiddleware())
+	router.Use(RequestLogger(observability.NewMetrics()))
+	router.GET("/watch/proxy/stream", func(c *gin.Context) {
+		c.Status(http.StatusBadGateway)
+	})
+
+	req := httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/watch/proxy/stream?token=abc", nil)
+	rec := httptest.NewRecorder()
+	router.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusBadGateway {
+		t.Fatalf("status = %d, want %d", rec.Code, http.StatusBadGateway)
+	}
+	if got := logs.String(); !strings.Contains(got, " ERROR http 502 GET /watch/proxy/stream") {
+		t.Fatalf("expected failed stream proxy log, got %s", got)
+	}
+}
+
 func TestRespondErrorIncludesRequestContext(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 

static/player/main.ts

@@ -156,13 +156,27 @@ const initPlayer = async (): Promise<void> => {
 
   await ensurePreferredModeSource(signal);
 
+  const resumeAfterModeSwitch = (() => {
+    try {
+      const raw = sessionStorage.getItem("mal:resume-after-mode-switch");
+      if (raw === null) return null;
+      sessionStorage.removeItem("mal:resume-after-mode-switch");
+      const parsed = Number(raw);
+      return Number.isFinite(parsed) && parsed >= 0 ? parsed : null;
+    } catch (error) {
+      console.error("failed to parse resume state:", error);
+      return null;
+    }
+  })();
+  const initialStartTime = resumeAfterModeSwitch ?? state.playback.startTimeSeconds;
+
   // build video src from mode, token, and saved quality preference
   const preferredQuality = safeLocalStorage.getItem("mal:preferred-quality") || "best";
   const streamToken = state.playback.modeSources[state.playback.currentMode]?.token;
   if (streamToken) {
     const source = state.playback.modeSources[state.playback.currentMode];
     const url = `${state.playback.streamURL}?mode=${encodeURIComponent(state.playback.currentMode)}&token=${encodeURIComponent(streamToken)}${source?.type === "m3u8" ? "&hls=1" : ""}${preferredQuality !== "best" ? `&quality=${encodeURIComponent(preferredQuality)}` : ""}`;
-    loadVideoSource(url, source?.type);
+    loadVideoSource(url, source?.type, initialStartTime);
   }
 
   updateSubtitleOptions();
@@ -190,20 +204,6 @@ const initPlayer = async (): Promise<void> => {
     const resumeTime = bounds.duration > 0 ? Math.min(startTime, bounds.duration) : 0;
     const isAtEnd = startTime > 0 && bounds.duration > 0 && startTime >= bounds.duration - 2;
 
-    // Resume after a mode-switch page reload (best effort, session-scoped).
-    const resumeAfterModeSwitch = (() => {
-      try {
-        const raw = sessionStorage.getItem("mal:resume-after-mode-switch");
-        if (raw === null) return null;
-        sessionStorage.removeItem("mal:resume-after-mode-switch");
-        const parsed = Number(raw);
-        return Number.isFinite(parsed) && parsed >= 0 ? parsed : null;
-      } catch (error) {
-        console.error("failed to parse resume state:", error);
-        return null;
-      }
-    })();
-
     if (resumeAfterModeSwitch !== null) {
       const clamped = bounds.duration > 0 ? Math.min(resumeAfterModeSwitch, bounds.duration) : 0;
       if (clamped > 0) {
@@ -425,7 +425,9 @@ const initPlayer = async (): Promise<void> => {
   }
 
   setupThumbnails();
-  void hydrateAlternateMode(signal);
+  window.setTimeout(() => {
+    if (!signal.aborted) void hydrateAlternateMode(signal);
+  }, 3000);
 
   document.body.addEventListener(
     "htmx:beforeSwap",

static/player/video.ts

@@ -38,7 +38,7 @@ const shouldUseHLS = (type: string | undefined, url: string): boolean => {
  * Some browsers can be flaky when switching between HLS URLs while playing.
  * Clearing `src` first ensures the media element fully resets before the new URL is set.
  */
-export const loadVideoSource = (url: string, type?: string): void => {
+export const loadVideoSource = (url: string, type?: string, startTimeSeconds?: number): void => {
   if (!url) return;
 
   const wasPlaying = !state.elements.video.paused;
@@ -49,10 +49,24 @@ export const loadVideoSource = (url: string, type?: string): void => {
   destroyVideoSource();
 
   if (shouldUseHLS(type, url) && Hls.isSupported()) {
-    hls = new Hls();
+    hls = new Hls({
+      autoStartLoad: false,
+      backBufferLength: 30,
+      maxBufferLength: 18,
+      maxMaxBufferLength: 30,
+      maxBufferSize: 20 * 1000 * 1000,
+      startFragPrefetch: false,
+    });
     stopHLSProfile = attachHLSProfile(hls, state.elements.video);
     hls.loadSource(url);
     hls.attachMedia(state.elements.video);
+    hls.once(Hls.Events.MEDIA_ATTACHED, () => {
+      const startPosition =
+        startTimeSeconds !== undefined && Number.isFinite(startTimeSeconds) && startTimeSeconds > 0
+          ? startTimeSeconds
+          : -1;
+      hls?.startLoad(startPosition);
+    });
   } else {
     state.elements.video.src = url;
     state.elements.video.load();