You need to add playercorefactory.xml to that directory, it's not present by default.
The problem you'll have is finding a valid app to play the video on Dune. You need the Dune video app and it needs to be able to accept being called from Kodi. I don't know if this is possible.
A very basic sample playercorefactory, calling mxplayer for all video is here.
<playercorefactory>
<players>
<player name="MXPlayer" type="ExternalPlayer" audio="false" video="true">
<filename>com.mxtech.videoplayer.ad</filename>
<hidexbmc>true</hidexbmc>
<playcountminimumtime>120</playcountminimumtime>
</player>
</players>
<rules action="prepend">
<rule video="true" player="MXPlayer"/>
</rules>
</playercorefactory>
See here for more info: https://kodi.wiki/view/HOW-TO:Use_external_players_on_Android