title: unrecognized option '-vf' in ffmpeg
body: <p>I am running this command </p>
  
  <pre><code>ffmpeg -i "video_in.mp4" -vf "movie=watermark.png [watermark]; [in][watermark] overlay=main_w/2-overlay_w/2:main_h/2-overlay_h/2 [out]" outputvideo.mp4
  </code></pre>
  
  <p>also tried</p>
  
  <pre><code>/usr/local/bin/ffmpeg -i "video_in.mp4" -vf "movie=watermark.png [watermark]; [in][watermark] overlay=main_w/2-overlay_w/2:main_h/2-overlay_h/2 [out]" outputvideo.mp4
  </code></pre>
  
  <p><strong>Error</strong> : unrecognized option '-vf' in ffmpeg</p>