title: difference between <video src=""> </video > and <video> <source> </video>?
body: <p>Could you please explain me the difference between</p>
  <pre><code>&lt;video src=&quot;&quot;&gt; &lt;/video&gt;
  </code></pre>
  <p>and</p>
  <pre><code>&lt;video&gt;
      &lt;source src=&quot;&quot;&gt;
  &lt;/video&gt;
  </code></pre>
  <p>?</p>