title: Gstreamer change source on PLAYING state
body: <p>Hello guys I wanna know how can I switch between different sources in my pipeline without changing state for example if I have :</p>
  
  <h1>Source 1</h1>
  
  <pre><code> filesrc location=file1 ! decodebin ! autovideosink
  </code></pre>
  
  <h1>Source 2</h1>
  
  <pre><code> filesrc location=file2 ! decodebin ! autovideosink
  </code></pre>
  
  <h1>Source 3</h1>
  
  <pre><code> filesrc location=file3 ! decodebin ! autovideosink
  </code></pre>
  
  <p>I want to accomplish something like switching between channels on TV. Is it possible to change location property dynamically ? I searched over and over and didn't found anything specific.If you could point me to some code examples <code>C</code> or <code>python</code> I would be grateful.</p>