It is simply not possible to convert or otherwise export multimedia playlists cannot be converted to actual multimedia files. For example .mpl file contains just a list of videos or music to be played in a sequence with a media player, not the actual multimedia files, which means that mpl to wav conversion is not possible.
But of course you can manually open the playlist using a text editor and check the location of the actual audio files. If the playlist is not yours, it is unlikely you will find them thought.Open MPL file Open WAV file
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