title: Low Light h.264 IR CCTV stream frame noise reduction
body: <p>We want to improve the image quality of individual grayscale frames grabbed from a h.264 stream captured under low light conditions. The input hardware is a CCTV camera set to IR night mode. 
  We are using OpenCV cv::VideoCapture class to get individual frames from the video stream over RTSP. The h.264 video stream under the low light conditions appears to be less noisy (to the human eye) compared to individual frames grabbed from the stream.
  Our questions are:</p>
  
  <ol>
  <li>Is there a recommended method to grab frames from h.264 stream which
  will result in less noisy frames or reduce compression artifacts in low light conditions ?  </li>
  <li>Can multiple frames be combined to get a better frame ? We are experimenting with
      cv::fastNlMeansDenoisingMulti() with a sequence of frames. This
      results in removing some details along with noise from the image frames.</li>
  </ol>