diff --git a/apps/web/src/pages/generate/components/FrontendPreviewPlayer.tsx b/apps/web/src/pages/generate/components/FrontendPreviewPlayer.tsx
index 531af36ef..bd8bf2b82 100644
--- a/apps/web/src/pages/generate/components/FrontendPreviewPlayer.tsx
+++ b/apps/web/src/pages/generate/components/FrontendPreviewPlayer.tsx
@@ -52,9 +52,16 @@ function buildPlaybackSegments(
     const startTime = 0
     const endTime = Math.min(startTime + segDuration, assetDuration)
 
+    const videoUrl = asset.file_url || asset.storage_key
+
+    // 调试日志：打印每个片段的 videoUrl
+    console.log(
+      `[buildPlaybackSegments] 片段 ${i}: assetId=${asset.id}, videoUrl=${videoUrl}, file_url=${asset.file_url}, storage_key=${asset.storage_key}`,
+    )
+
     segments.push({
       assetId: asset.id,
-      videoUrl: asset.file_url || asset.storage_key,
+      videoUrl,
       startTime,
       endTime,
       order: i,
diff --git a/apps/web/src/pages/generate/components/PreviewVideoPanel.tsx b/apps/web/src/pages/generate/components/PreviewVideoPanel.tsx
index 2976a8156..430a44713 100644
--- a/apps/web/src/pages/generate/components/PreviewVideoPanel.tsx
+++ b/apps/web/src/pages/generate/components/PreviewVideoPanel.tsx
@@ -103,6 +103,7 @@ function buildTitleStyle(settings: TitleSettings): React.CSSProperties {
 
 /**
  * CSS 标题预览覆盖层
+ * 始终渲染：有标题显示标题，无标题显示占位文本"标题预览"
  */
 const TitleOverlay: React.FC<{ titleSettings: TitleSettings }> = ({ titleSettings }) => {
   const positionStyle = useMemo(
@@ -124,7 +125,8 @@ const TitleOverlay: React.FC<{ titleSettings: TitleSettings }> = ({ titleSetting
     ],
   )
 
-  if (!titleSettings.title?.trim()) return null
+  // 标题为空时显示占位文本
+  const displayTitle = titleSettings.title?.trim() || "标题预览"
 
   return (
     <div
@@ -143,7 +145,7 @@ const TitleOverlay: React.FC<{ titleSettings: TitleSettings }> = ({ titleSetting
           position: "absolute",
         }}
       >
-        {titleSettings.title}
+        {displayTitle}
       </div>
     </div>
   )
@@ -160,7 +162,6 @@ export const PreviewVideoPanel: React.FC<PreviewVideoPanelProps> = ({
   titleSettings,
 }) => {
   const videoAspectStyle = { aspectRatio: (videoRatio || "16:9").replace(":", "/") }
-  const hasTitle = !!titleSettings?.title?.trim()
 
   return (
     <div className="xx-generate-preview">
@@ -200,8 +201,9 @@ export const PreviewVideoPanel: React.FC<PreviewVideoPanelProps> = ({
         )}
 
         {/* CSS 标题实时预览层 — 与 FFmpeg ASS 渲染坐标对齐
-            始终渲染在内容层之上（z-index: 30），只要 titleSettings 有标题文字就显示 */}
-        {hasTitle && <TitleOverlay titleSettings={titleSettings!} />}
+            始终渲染在内容层之上（z-index: 30）
+            有标题显示标题，无标题显示"标题预览"占位文本 */}
+        {titleSettings && <TitleOverlay titleSettings={titleSettings} />}
       </div>
 
       {/* 素材信息 */}
diff --git a/apps/web/src/pages/generate/hooks/useSegmentScheduler.ts b/apps/web/src/pages/generate/hooks/useSegmentScheduler.ts
index 28d430bd5..8cd05cf96 100644
--- a/apps/web/src/pages/generate/hooks/useSegmentScheduler.ts
+++ b/apps/web/src/pages/generate/hooks/useSegmentScheduler.ts
@@ -109,34 +109,69 @@ export function useSegmentScheduler(segments: PlaybackSegment[]): SegmentSchedul
     ? currentTime - (timelineStarts[currentSegmentIndex] || 0) + currentSegment.startTime
     : 0
 
-  /** 切换到指定片段 */
+  /** 切换到指定片段，返回 Promise 在视频可播放后 resolve */
   const switchToSegment = useCallback(
-    (index: number, seekToLocalTime?: number) => {
-      const video = videoRef.current
-      if (!video || index >= segments.length) return
-
-      const seg = segments[index]
-      video.src = seg.videoUrl
-
-      const localTime = seekToLocalTime ?? seg.startTime
-      // 等待 src 设置后再设置 currentTime
-      const onLoaded = () => {
-        video.currentTime = localTime
-        video.removeEventListener("loadedmetadata", onLoaded)
-      }
-      video.addEventListener("loadedmetadata", onLoaded)
-
-      setCurrentSegmentIndex(index)
-
-      // 预加载下一段
-      if (index + 1 < segments.length) {
-        const nextSeg = segments[index + 1]
-        if (!preloadVideoRef.current) {
-          preloadVideoRef.current = document.createElement("video")
-          preloadVideoRef.current.preload = "auto"
+    (index: number, seekToLocalTime?: number): Promise<void> => {
+      return new Promise((resolve) => {
+        const video = videoRef.current
+        if (!video || index >= segments.length) {
+          resolve()
+          return
         }
-        preloadVideoRef.current.src = nextSeg.videoUrl
-      }
+
+        const seg = segments[index]
+        const videoUrl = seg.videoUrl
+
+        // 调试日志：检查 videoUrl 是否有效
+        if (!videoUrl || videoUrl === "") {
+          console.error(
+            `[useSegmentScheduler] 片段 ${index} 的 videoUrl 为空！assetId: ${seg.assetId}`,
+          )
+          resolve()
+          return
+        }
+
+        // 检查是否是完整的 HTTP URL
+        if (!videoUrl.startsWith("http://") && !videoUrl.startsWith("https://")) {
+          console.warn(
+            `[useSegmentScheduler] 片段 ${index} 的 videoUrl 不是完整 URL: ${videoUrl}，可能导致加载失败`,
+          )
+        }
+
+        video.src = videoUrl
+
+        const localTime = seekToLocalTime ?? seg.startTime
+        // 等待 src 设置后再设置 currentTime 并 resolve
+        const onLoaded = () => {
+          video.currentTime = localTime
+          video.removeEventListener("loadedmetadata", onLoaded)
+          resolve()
+        }
+        video.addEventListener("loadedmetadata", onLoaded)
+
+        // 监听加载错误
+        const onError = () => {
+          console.error(
+            `[useSegmentScheduler] 视频加载失败: ${videoUrl}`,
+            video.error?.message || "unknown error",
+          )
+          video.removeEventListener("error", onError)
+          resolve() // 即使失败也 resolve，让调用方继续处理
+        }
+        video.addEventListener("error", onError)
+
+        setCurrentSegmentIndex(index)
+
+        // 预加载下一段
+        if (index + 1 < segments.length) {
+          const nextSeg = segments[index + 1]
+          if (!preloadVideoRef.current) {
+            preloadVideoRef.current = document.createElement("video")
+            preloadVideoRef.current.preload = "auto"
+          }
+          preloadVideoRef.current.src = nextSeg.videoUrl
+        }
+      })
     },
     [segments],
   )
@@ -156,7 +191,7 @@ export function useSegmentScheduler(segments: PlaybackSegment[]): SegmentSchedul
     if (video.currentTime >= seg.endTime - 0.15) {
       const nextIndex = currentSegmentIndex + 1
       if (nextIndex < segments.length) {
-        // 切到下一段
+        // 切到下一段（不等待，直接继续 tick）
         switchToSegment(nextIndex)
         const accumulatedTime =
           (timelineStarts[currentSegmentIndex] || 0) + (seg.endTime - seg.startTime)
@@ -186,18 +221,21 @@ export function useSegmentScheduler(segments: PlaybackSegment[]): SegmentSchedul
 
     setIsEnded(false)
 
-    // 如果还没设置 src（首次播放），先加载第一段
+    // 如果还没设置 src（首次播放），先加载第一段并等待
     if (!video.src || video.src === "") {
-      switchToSegment(0)
+      console.log("[useSegmentScheduler] 首次播放，加载片段 0...")
+      await switchToSegment(0)
+      // switchToSegment 会等待 loadedmetadata
     }
 
     try {
       await video.play()
+      console.log("[useSegmentScheduler] 播放开始")
       setIsPlaying(true)
       rafRef.current = requestAnimationFrame(tick)
-    } catch {
+    } catch (err) {
       // 自动播放可能被浏览器阻止，忽略
-      console.warn("[useSegmentScheduler] auto-play blocked by browser")
+      console.warn("[useSegmentScheduler] 播放失败:", err)
     }
   }, [canPlay, switchToSegment, tick])
 
@@ -217,18 +255,15 @@ export function useSegmentScheduler(segments: PlaybackSegment[]): SegmentSchedul
       if (isEnded) {
         // 播放结束后再次播放，从头开始
         setIsEnded(false)
-        switchToSegment(0, segments[0]?.startTime)
-        const video = videoRef.current
-        if (video) {
-          const onSeeked = () => {
+        switchToSegment(0, segments[0]?.startTime).then(() => {
+          const video = videoRef.current
+          if (video) {
             video.play().catch(() => {})
             setIsPlaying(true)
             setCurrentTime(0)
             rafRef.current = requestAnimationFrame(tick)
-            video.removeEventListener("seeked", onSeeked)
           }
-          video.addEventListener("seeked", onSeeked)
-        }
+        })
       } else {
         play()
       }
@@ -237,7 +272,7 @@ export function useSegmentScheduler(segments: PlaybackSegment[]): SegmentSchedul
 
   /** 跳转到指定全局时间 */
   const seekTo = useCallback(
-    (time: number) => {
+    async (time: number) => {
       const video = videoRef.current
       if (!video || !canPlay) return
 
@@ -248,9 +283,7 @@ export function useSegmentScheduler(segments: PlaybackSegment[]): SegmentSchedul
 
       // 如果片段变了，需要切换 src
       if (index !== currentSegmentIndex) {
-        switchToSegment(index, localTime)
-        // switchToSegment 会设置 src 并在 loadedmetadata 后设置 currentTime
-        // 所以这里不需要再设置
+        await switchToSegment(index, localTime)
       } else {
         video.currentTime = localTime
       }