title: Transfer custom (all) metadata using ffmpeg
body: <p>How to transfer metadata using FFMPEG or other tools with CMD ?</p>
  
  <p>I'm trying to encode video/audio and since they already have metadata inside obviously i want to preserve them into my new file</p>
  
  <p>btw since i'm using mediamonkey as main player, there's also some Custom metadata. this is the one who wont transfer</p>
  
  <ul>
  <li>for Video output file using mp4/mkv (using x264)</li>
  <li>for Audio output file using m4a (using neroAac) </li>
  </ul>
  
  <p>Thank You!</p>
  
  <p>ps. which container is best for <strong>neroAac</strong> and x264? since i can't seem to edit mkv metadata (when i remove from mediamonkey playlist, they're all gone), mp4 is fine though and i can't seem to play AAC, although it's fine when muxed into video</p>