Add watermark for 30seconds

[Shaorin]

How do I add a watermark and show it for only 30 seconds? this is what I got in avisynth

DirectShowSource("C:\Users\Susan\Documents\Videos\video.mp4", fps=29.970, audio=false, convertfps=true).AssumeFPS(30000,1001)

a2=ImageReader("C:\Users\Susan\Documents\Lovely Anime\logo2.png")
a3=ImageReader("C:\Users\Susan\Documents\Lovely Anime\logo2.png",pixel_type="RGB32").ShowAlpha(pixel_type="RGB32")
Overlay(a2,mask=a3,x=5,y=5,opacity=1)

[poisondeathray]

use trim with aligned splice (++)

I'm assuming you mean the 1st 30 seconds

a1=DirectShowSource("C:\Users\Susan\Documents\Videos\video.mp4", fps=29.970, audio=false, convertfps=true).AssumeFPS(30000,1001)  

a2=ImageReader("C:\Users\Susan\Documents\Lovely Anime\logo2.png") 
a3=ImageReader("C:\Users\Susan\Documents\Lovely Anime\logo2.png",pixel_type="RGB32").ShowAlpha(pixel_type="RGB32") 
Overlay(a1,a2,mask=a3,x=5,y=5,opacity=1)
logo=last

logo.trim(0,899) ++ a1.trim(900,0)