title: Error in converting a MOV video into MP4 using ffmpeg
body: <p>I want to convert a mov video into mp4 using ffmpef library of php.
  I am using given code:</p>
  
  <pre><code>$cmd='ffmpeg -i sample.mov -sameq output.mp4';
  echo exec($cmd);
  </code></pre>
  
  <p>It is not working at all. Even I didn't get any error. Could anyone tell me the proper steps to do this conversion. I have tried a lot of code examples but not working for me.</p>