I have an xml file with dynamic contents like this.
<?xml version="1.0" encoding="UTF-8"?>
<config>
  <tracks>
    <idx>0</idx>
    <path>/mnt/HD/HD_a2/mymusic/Worth It - Fifth Harmony - ft. Kid Ink.mp3</path>
  </tracks>
  <tracks>
    <idx>1</idx>
    <path>/mnt/HD/HD_a2/mymusic/Flashlight - Jessie J.mp3</path>
  </tracks>
  <tracks>
    <idx>2</idx>
    <path>/mnt/HD/HD_a2/mymusic/価値がある.mp3</path>
  </tracks>
</config>
And also a php file which creates another xml file according to data fetch on first xml. Here's a piece of code in generating new xml:
$item = $xml->addChild('tracks');
$item->addChild('artist', base64_encode($mp3Artist));
$item->addChild('song_name', base64_encode($mp3Title));
$item->addChild('song_path', base64_encode($file)); 
$item->addChild('album', base64_encode($mp3Album));
However, when I encode /mnt/HD/HD_a2/mymusic/価値がある.mp3
the output is L21udC9IRC9IRF9hMi9teW11c2ljL+S+oeWApOOBjOOBguOCiy5tcDM= which is when I decode it again, the value becomes /mnt/HD/HD_a2/mymusic/価値ãŒã‚ã‚‹.mp3
but when I decode it on this site https://www.base64decode.org/ with utf-8 encoding, the output is the same as the first one which is /mnt/HD/HD_a2/mymusic/価値がある.mp3
So my question is, how can I achieved utf-8 encoding on php's base64_encode to output the exactly the same as on www.base64decode.org? Any help will be much appreciated.
 
    