🐛 fix(video_subtitle_embedding): 确保视频和字幕嵌入准备就绪

composables/useVideoSubtitleEmbedding.ts

@@ -43,6 +43,7 @@ export const useVideoSubtitleEmbedding = async (
     new MP4Clip((await fetch(videoUrl)).body!)
   );
   videoSprite.time = { duration: 10e6, offset: 0 };
+  await videoSprite.ready;
 
   const srtSprite = new OffscreenSprite(
     new EmbedSubtitlesClip(await (await fetch(srtUrl)).text(), {
@@ -60,6 +61,7 @@ export const useVideoSubtitleEmbedding = async (
       ...options,
     })
   );
+  await srtSprite.ready;
   srtSprite.time = { duration: 10e6, offset: 0 };
 
   const combinator = new Combinator({