fix: 字幕预览scale基于视频实际分辨率，修复预览与实际比例不一致

tauri-app/src/hooks/useCanvasSubtitleRenderer.ts

@@ -80,8 +80,9 @@ export function useCanvasSubtitleRenderer(options: UseCanvasSubtitleRendererOpti
     // 清空画布
     ctx.clearRect(0, 0, displayWidth, displayHeight);
 
-    // 计算缩放比例（基于高度）
-    const scale = displayHeight / PLAY_RES_Y;
+    // 计算缩放比例：以视频实际分辨率或 ASS PlayResY 为基准，确保预览与实际一致
+    const playResY = video.videoHeight || PLAY_RES_Y;
+    const scale = displayHeight / playResY;
 
     const currentTimeMs = video.currentTime * 1000;
 

tauri-app/src/pages/VideoCreation/SubtitleBurning.tsx

@@ -181,7 +181,7 @@ export default function SubtitleBurning() {
   const videoDurationMs = (alignment?.duration || 0) * 1000;
 
   const buildSubtitleStyle = (preset: TitlePreset): Partial<AssStyle> => ({
-    fontSize: 50,
+    fontSize: 56,
     primaryColor: htmlColorToAss(preset.primaryColor),
     outlineColor: htmlColorToAss(preset.outlineColor),
     backColor: htmlColorToAss(preset.backColor),