diff --git a/internal/app/playback_gateway.go b/internal/app/playback_gateway.go
index 9ca0a37..e5733c4 100644
--- a/internal/app/playback_gateway.go
+++ b/internal/app/playback_gateway.go
@@ -259,10 +259,16 @@ func (app *UIApp) handlePlaybackMediaAsset(writer http.ResponseWriter, request *
 		return
 	}
 	run, err := strconv.ParseUint(parts[1], 10, 64)
+	viewer := contextViewer(request.Context())
 	app.playbackMu.Lock()
 	session := app.playbacks[parts[0]]
-	if err != nil || !viewerOwnsPlayback(request.Context(), session) || session.run != run || session.media == nil {
+	denied := err != nil || session == nil || session.run != run || session.media == nil
+	if !denied && viewer != nil {
+		denied = !viewerOwnsPlayback(request.Context(), session)
+	}
+	if denied {
 		app.playbackMu.Unlock()
+		app.recordPlaybackAssetDenial(request, "session-unavailable")
 		writer.WriteHeader(http.StatusGone)
 		return
 	}
diff --git a/internal/app/ui_playback.go b/internal/app/ui_playback.go
index 89cc479..8848078 100644
--- a/internal/app/ui_playback.go
+++ b/internal/app/ui_playback.go
@@ -94,6 +94,17 @@ func (app *UIApp) registerPlaybackRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("/api/ui/playback/progress", app.handlePlaybackProgress)
 }
 
+// recordPlaybackAssetDenial 记录媒体资产请求被拒的情况，便于诊断
+// iOS/WebKit 原生媒体管线的拉流失败（区分会话失效与观看者不匹配）。
+func (app *UIApp) recordPlaybackAssetDenial(request *http.Request, reason string) {
+	agent := request.UserAgent()
+	if len(agent) > 120 {
+		agent = agent[:120]
+	}
+	app.downloader.recordDiagnostic(diagnosticEvent{Level: "warn", Event: "playback.asset.denied",
+		HTTPStatus: http.StatusGone, Message: reason + " ua=" + agent})
+}
+
 func playbackRequestAllowed(writer http.ResponseWriter, request *http.Request, method string) bool {
 	writer.Header().Set("Cache-Control", "private, no-store, no-transform")
 	writer.Header().Set("X-Accel-Buffering", "no")
diff --git a/internal/app/ui_playback_native.go b/internal/app/ui_playback_native.go
index ad06015..d535975 100644
--- a/internal/app/ui_playback_native.go
+++ b/internal/app/ui_playback_native.go
@@ -95,10 +95,16 @@ func (app *UIApp) handlePlaybackNativeAsset(writer http.ResponseWriter, request
 		writeJSON(writer, http.StatusBadRequest, map[string]string{"error": "播放请求编号无效"})
 		return
 	}
+	viewer := contextViewer(request.Context())
 	app.playbackMu.Lock()
 	session := app.playbacks[query.Get("session")]
-	if !viewerOwnsPlayback(request.Context(), session) || session.run != run || session.native == nil {
+	denied := session == nil || session.run != run || session.native == nil
+	if !denied && viewer != nil {
+		denied = !viewerOwnsPlayback(request.Context(), session)
+	}
+	if denied {
 		app.playbackMu.Unlock()
+		app.recordPlaybackAssetDenial(request, "stream-unavailable")
 		writeJSON(writer, http.StatusGone, map[string]string{"error": "此播放流已结束，请重新选择分集"})
 		return
 	}
diff --git a/internal/app/ui_viewer.go b/internal/app/ui_viewer.go
index c2706ae..a3e505c 100644
--- a/internal/app/ui_viewer.go
+++ b/internal/app/ui_viewer.go
@@ -207,6 +207,12 @@ func viewerOwnsPlayback(ctx context.Context, session *playbackSession) bool {
 	return viewer != nil && session != nil && session.viewer == viewer && playbackSourceAllowed(ctx, session)
 }
 
+// playbackCapabilityPath 判断是否为无需 viewer cookie 的媒体资产路径：
+// 这些 URL 中已包含不可猜测的播放会话 ID，可作为独立能力凭证。
+func playbackCapabilityPath(path string) bool {
+	return strings.HasPrefix(path, "/api/ui/playback/media/") || path == "/api/ui/playback/hls/index.m3u8" || path == "/api/ui/playback/hls/segment.ts"
+}
+
 func writeViewerError(writer http.ResponseWriter, status int, code, message string) {
 	writer.Header().Set("Cache-Control", "private, no-store")
 	writer.Header().Add("Vary", "Cookie")
@@ -234,6 +240,12 @@ func (app *UIApp) withBrowserViewer(next http.Handler) http.Handler {
 		}
 		identity := manager.identity(request)
 		if account.ID == "" && (identity == "" || accountCookie) {
+			if playbackCapabilityPath(path) {
+				// AVPlayer 等原生媒体管线可能不携带 cookie；播放会话 ID 本身即能力凭证，
+				// 由媒体资产接口自行校验会话与运行编号。
+				next.ServeHTTP(writer, request)
+				return
+			}
 			writeViewerError(writer, http.StatusUnauthorized, "viewer_required", "请刷新页面，恢复此浏览器的独立观看记录")
 			return
 		}