title: Android: video files have black thumbnails
body: <p>I have to write a program where all the videos store in my device to be shown with thumbnails.
  i am able to list them all but most of them are coming with black thumbnail while in gallery application those shows perfectly.</p>
  
  <p>please help me!
  what i have tried is</p>
  
  <pre><code>MediaStore.Video.Thumbnails.getThumbnail(mContex.getContentResolver(), id, MediaStore.Video.Thumbnails.MICRO_KIND, null);
  </code></pre>
  
  <p>or</p>
  
  <pre><code>ThumbnailUtils.createVideoThumbnail(filePath, MediaStore.Video.Thumbnails.MICRO_KIND)
  </code></pre>