title: Confusion regarding the image format NV21 and the different memory layouts it seems to have
body: <p>I have to deal with images in the format given above. However, I have found conflicting information about it.</p>
  
  <p>According to <a href="https://stackoverflow.com/questions/5272388/extract-black-and-white-image-from-android-cameras-nv21-format">another stack overflow answer</a> the UV values follow eachother, while according to <a href="https://en.wikipedia.org/wiki/YUV" rel="nofollow noreferrer">Wikipedia</a> the V values lie AFTER the U values in memory. Which one is correct, or if they both are, what is the difference? </p>
  
  <p>Could it be a NV12 vs NV21 problem? However, <a href="http://www.fourcc.org/yuv.php" rel="nofollow noreferrer">this</a> site states that they should simply be switched. </p>
  
  <p>Maybe it has something to do with the image being planar, semi-planar or not planar, though I have no idea what these terms mean.</p>
  
  <p>Can someone clarify this a bit? </p>