title: ffmpeg is not being detected by Spyder
body: <p>Running almost every code from OpenAi gym in spyder by Anaconda (for instance this code: <a href="https://gym.openai.com/evaluations/eval_y5dnhk0ZSMqlqJKBz5vJQw" rel="noreferrer">https://gym.openai.com/evaluations/eval_y5dnhk0ZSMqlqJKBz5vJQw</a> )
  I run into the following error message:</p>
  
  <pre><code>DependencyNotInstalled: Found neither the ffmpeg nor avconv executables. On OS X, you can install ffmpeg via 'brew install ffmpeg'. On most Ubuntu variants, 'sudo apt-get install ffmpeg' should do it. On Ubuntu 14.04, however, you'll need to install avconv with 'sudo apt-get install libav-tools'.
  </code></pre>
  
  <p>However when I type <code>brew install ffmpeg</code> in terminal, I get <code>Warning: ffmpeg-3.2 already installed</code> and nothing happens.</p>
  
  <p>Any ideas on how to fix this error?</p>