diff --git a/apps/web/src/pages/generate/hooks/useCanvasPlayer.ts b/apps/web/src/pages/generate/hooks/useCanvasPlayer.ts
index 812858d0c..79d8a8267 100644
--- a/apps/web/src/pages/generate/hooks/useCanvasPlayer.ts
+++ b/apps/web/src/pages/generate/hooks/useCanvasPlayer.ts
@@ -81,47 +81,6 @@ function findCodecConfigRecursive(
   return undefined
 }
 
-/**
- * 从 MP4 buffer 中解析视频轨道的旋转角度。
- * iOS HEVC 竖屏视频用 rotation=90° 元数据标记，
- * mp4box.js 的 track_width/track_height 不反映旋转后的尺寸。
- */
-function extractVideoRotation(buffer: ArrayBuffer): number {
-  try {
-    const view = new DataView(buffer)
-    let offset = 0
-    while (offset < buffer.byteLength - 8) {
-      const size = view.getUint32(offset)
-      const type = String.fromCharCode(
-        view.getUint8(offset + 4),
-        view.getUint8(offset + 5),
-        view.getUint8(offset + 6),
-        view.getUint8(offset + 7),
-      )
-      if (size <= 0 || offset + size > buffer.byteLength) break
-      if (type === "tkhd") {
-        const version = view.getUint8(offset + 8)
-        const matrixOffset = offset + (version === 0 ? 28 : 40)
-        if (matrixOffset + 36 <= offset + size) {
-          const a = view.getInt32(matrixOffset)
-          const b = view.getInt32(matrixOffset + 4)
-          if (Math.abs(b) > 0x00008000) {
-            return b > 0 ? 90 : 270
-          }
-          if (a < -0x00008000) {
-            return 180
-          }
-          return 0
-        }
-      }
-      offset += size
-    }
-  } catch {
-    // 解析失败不阻塞，返回 0
-  }
-  return 0
-}
-
 // ── 帧队列（环形缓冲区） ──
 interface FrameEntry {
   frame: VideoFrame
@@ -411,18 +370,6 @@ export function useCanvasPlayer(
             samples: [],
           }
 
-          // ═══ 新增：检测旋转元数据，交换宽高 ═══
-          const rotation = extractVideoRotation(buffer)
-          if (rotation === 90 || rotation === 270) {
-            const tmpW = meta.videoWidth
-            meta.videoWidth = meta.videoHeight
-            meta.videoHeight = tmpW
-            console.log(
-              `[useCanvasPlayer] Rotation ${rotation}° detected, swapped dimensions to ${meta.videoWidth}x${meta.videoHeight}`,
-            )
-          }
-          // ═══ 新增结束 ═══
-
           // 提取所有 samples
           mp4File.setExtractionOptions(videoTrack.id ?? 1, null, {
             nbSamples: Infinity, // 提取所有 sample
@@ -510,6 +457,11 @@ export function useCanvasPlayer(
       // 配置解码器（每个片段可能需要不同的 codec/分辨率）
       const decoder = new VideoDecoder({
         output: (frame: VideoFrame) => {
+          // 从第一帧获取实际尺寸
+          if (videoDimRef.current.width === 0 || videoDimRef.current.height === 0) {
+            videoDimRef.current = { width: frame.codedWidth, height: frame.codedHeight }
+            console.log(`[useCanvasPlayer] Actual frame size: ${frame.codedWidth}x${frame.codedHeight}`)
+          }
           const localTime = frame.timestamp / 1_000_000
           const globalTime = localTime + meta.globalStartTime
           frameQueueRef.current.push({
@@ -532,19 +484,8 @@ export function useCanvasPlayer(
       })
 
       try {
-        // ═══ 新增：旋转检测 ═══
-        const rotation = extractVideoRotation(_buffer)
-        if (rotation === 90 || rotation === 270) {
-          const tmpW = meta.videoWidth
-          meta.videoWidth = meta.videoHeight
-          meta.videoHeight = tmpW
-        }
-        // ═══ 新增结束 ═══
-
         await decoder.configure({
           codec: meta.codec,
-          codedWidth: meta.videoWidth,
-          codedHeight: meta.videoHeight,
           ...(meta.description ? { description: meta.description } : {}),
         })
         decoderRef.current = decoder