title: avisinth text effect up and down (ideas for down?)
body: <p>I wrote a script to write some text into a video clip with some effect is not clear how it work (but work)</p>
  
  <pre><code>        a=AVIFileSource("C:\downloads\FREE.avi")
  #take file free.avi 
      ovText = "AviSynth Authors:"+chr(13)+
          \ "----------------------------"+chr(13)+
  
          \ ""
  #variable ovText some text in
      c = 4000
  # what shit is this c?
  t_mask = messageclip(ovText, height=c).converttoyv12().coloryuv(levels="tv-&gt;pc").trim(0,1)
  #and this? another variable
  
      t_blank = blankclip(t_mask, color=$ffffff)
  
      overlay(a, t_mask,x=199, mode="subtract")
      overlay(t_blank,x=200, mode="blend", mask=t_mask)
  
          frameevaluate("ol_x_offset = 400")
          frameevaluate("ol_y_offset = 256 - (current_frame)")
  
  #this frameevaluate take current frame value and put it into overlays so y value became t value e position value. I have text that go up from frame 256   
      Crop(0,0,0,0,align=true)
      Spline36Resize(720,480)
  </code></pre>
  
  <p>Now I have a video in which there's some text that go up, now I would like that text go down when end some ideas? </p>