Minor fixes

utils/CaptionRender.js

@@ -61,7 +61,11 @@ export class CaptionRenderer {
       let totalVideoDuration = 0;
 
       for (let j = 0; j < mediaFiles.length; j++) {
-        const clipDuration = Math.min(mediaFiles[j].durationSec, audioDuration - totalVideoDuration);
+        let mediaFileDuration = mediaFiles[j].prompt?.durationSec || mediaFiles[j].durationSec
+        if (j == mediaFiles.length - 1 && mediaFileDuration + totalVideoDuration < audioDuration) {
+          mediaFileDuration = audioDuration - totalVideoDuration;
+        }
+        const clipDuration = Math.min(mediaFileDuration, audioDuration - totalVideoDuration);
         if (clipDuration <= 0) break;
 
         const idx = sectionVideoStart + j;