title: ffmpeg: chain of multiple filter_complex, re-using intermediate output stream
body: <p>How can I apply two filter_complex commands sequentially?</p>
  
  <p>first, I want to blend a video with an image
  then I want to take the output of that filter and split it into 4 tiles, as described in this post <a href="https://stackoverflow.com/questions/33804431/multiple-crop-operations-on-input-video-using-ffmpeg">Stackoverflow</a>.</p>
  
  <p>I have tried this:
  (my strategy was to generate an intermediate output from filter_complex [int] and I wanted to re-use that output twice.</p>
  
  <pre><code>ffmpeg.exe 
  -i videoIn.avi 
  -i imageIn.avi 
  -filter_complex "[1:0] setsar=sar=1 [1sared];[0:0][1sared]blend=all_mode='divide':repeatlast=1[int];
  [int]crop=960:960:24:1055:[out1];
  [int]crop=960:960:1056:1062:[out2]" 
  -map [out1] out1.avi 
  -map [out2] out2.avi
  </code></pre>
  
  <p>however, I am getting an error:
  Stream specifier 'int' in filtergraph description [int]crop=960:960:24:1055[out1];[int]crop=960:960:1056:1062:[out2] matches no streams</p>
  
  <p>this code works if I only use one crop operation but not with two - so I am guessing the intermediate stream [int] cannot be re-used the way I am trying to do it?</p>
  
  <p>how can I re-use the intermediate stream multiple times for subsequent filters?</p>