a small bug fix

app.py

@@ -43,11 +43,11 @@ def apply_mask(image, mask, color, transparency=0.7):
     return out_image
 
 def process(text_query, full_video_path):
-    start_pt, end_pt = 0, 10
+    start_pt, max_end_pt = 0, 10
     input_clip_path = '/tmp/input.mp4'
     # extract the relevant subclip:
     with VideoFileClip(full_video_path) as video:
-        subclip = video.subclip(start_pt, end_pt)
+        subclip = video.subclip(start_pt, min(video.duration, max_end_pt))
         subclip.write_videofile(input_clip_path)
         
     checkpoint_path ='./refer-youtube-vos_window-12.pth.tar'