title: How to make dynamic timestamp in ffpmeg, not static?
body: <p>I am using ffmpeg (windows pc) with my webcam to record what happens when i'm out of home.
  It works fine, but i can't make dynamic clock and date on screen.
  I have tried</p>
  
  <pre><code>-vf "[in]drawtext=fontsize=12:fontfile=arial.ttf:text='%date%':x=10:y=25,  
  drawtext=fontsize=12:fontfile=arial.ttf:text="%TIME:~0,2%-%TIME:~3,2%-%TIME:~6,2%"
  </code></pre>
  
  <p>It works, but it shows time only for start moment, than it wont change during video recording.<br>
  it looks like:<img src="https://i.stack.imgur.com/srT0E.jpg" alt="enter image description here"><br>
  Is there any method to out time on screen?<br>
  Thanks.</p>