title: Create a new MP4 video and mux MP3 file into it
body: <p>I want to find a way to create a new MP4 container and add an MP3 file into it. Whether the MP3 file is to be encoded or not does not matter to me. Is there any easy way to do this without using <code>ffmpeg</code>? I have found the following example for muxing:</p>
  
  <p><a href="https://stackoverflow.com/questions/31572067/android-how-to-mux-audio-file-and-video-file">android - How to mux audio file and video file?</a></p>
  
  <p>Though, it has issues and also it is supposed to mux the audio file into an existing video.</p>
  
  <p>Can someone point me to a guide or at least in the right direction to accomplish what I need?</p>