需要：一张扩展后的首帧画面， 需要扩展的视频（最好是单一镜头，在剪映中导出带着黑边的需要扩展的尺寸。） seedance2.0图片＋视频参考

提示词：painting task. The black areas, which are the top and bottom extended background regions of the original 1:1（原视频尺寸） square video, must be filled. The central original video content is a completed photograph and must remain completely unchanged. Fill up the whole video（@视频）with the full image reference of（@图片）, ensuring seamless visual consistency, matching the reference image's lighting, style and content perfectly without any frame jump., maintain 15fps audio-video synchronization, strictly follow the 9:16（可调整） aspect ratio, and ensure the extended areas blend naturally with the original video content without obvious boundaries.

这样就能保证原视频画面内容不变，视频边缘画面进行成功视频扩展了。