Update

app.py

@@ -77,7 +77,7 @@ with gr.Blocks(css="style.css") as demo:
                     ('2-Step', 2),
                     ('4-Step', 4),
                     ('8-Step', 8)],
-                value='4-Step',
+                value=4,
                 interactive=True
             )
             submit = gr.Button(
@@ -87,6 +87,8 @@ with gr.Blocks(css="style.css") as demo:
     video = gr.Video(
         label='AnimateDiff-Lightning',
         autoplay=True,
+        height=512,
+        width=512
     )
 
     prompt.submit(