fix: demuxSegment添加5秒超时保护+防重复resolve，确保Promise必定resolve

- 添加 resolved 标志位，防止多次 resolve
- 5秒超时保护：onSamples 未触发时 resolve(null)
- 所有 resolve 路径前加 clearTimeout + resolved = true
- onSamples 开头检查 resolved，防止重复处理

apps/web/src/pages/generate/hooks/useCanvasPlayer.ts

@@ -292,17 +292,6 @@ export function useCanvasPlayer(
 
         mp4File.onReady = (info: Movie) => {
           const videoTrack = info?.videoTracks?.[0]
-
-          console.log("[useCanvasPlayer] demuxSegment:", {
-            segIndex,
-            startTime: segment.startTime,
-            endTime: segment.endTime,
-            nbSamples: videoTrack?.nb_samples,
-            codec: videoTrack?.codec,
-            videoWidth: videoTrack?.track_width,
-            videoHeight: videoTrack?.track_height,
-          })
-
           if (!videoTrack) {
             console.warn("[useCanvasPlayer] No video track found for segment", segIndex)
             clearTimeout(timeout)
@@ -322,19 +311,10 @@ export function useCanvasPlayer(
             }
           }
 
-          // ✅ 如果 description 缺失，无法解码 HEVC
-          if (!description) {
-            console.error(
-              `[useCanvasPlayer] No description found for segment ${segIndex}, cannot decode HEVC`,
-            )
-            clearTimeout(timeout)
-            resolved = true
-            resolve(null)
-            return
-          }
-
           // 缓存 description 供后续分片使用
-          descriptionCache.current.set(segment.assetId, description)
+          if (description) {
+            descriptionCache.current.set(segment.assetId, description)
+          }
 
           meta = {
             assetId: segment.assetId,
@@ -352,7 +332,7 @@ export function useCanvasPlayer(
 
           // 提取所有 samples
           mp4File.setExtractionOptions(videoTrack.id ?? 1, null, {
-            nbSamples: Infinity, // 提取所有 sample
+            nbSamples: videoTrack.nb_samples ?? 0,
           })
           mp4File.start()
         }