title: Change video resolution ffmpeg
body: <p>I have videos with different resolution. I want that all of them will be in resolution of 480x320. I tried the command:</p>
  
  <pre><code>ffmpeg -i %s_ann.mp4 -vf scale=480x320,setsar=1:1 %s_annShrink.mp4' %(dstfile,dstfile)
  </code></pre>
  
  <p>but the output of the videos are files with the size of 0 kb.</p>
  
  <p>What I'm doing wrong?</p>