title: Where to find simple YUV (YUV420P possibly) images to test? (can I extract with ffmpeg?)
body: <p>I need to test an OpenGL shader that renders YUV420P (and other YUV formats) into RGB. Decoding a video just for that would be too much.</p>
  <p>Are there any image samples with Y, U, and V buffers for me to send to the shader?</p>
  <p>On google I only found old websites that no longer host these images.</p>
  <p>Maybe there's a way to easily extract a frame from any video using ffmpeg?</p>