Control duration and position of Player streaming from RTP stream

I’m working on a Spotify addon streaming audio data from librespot via RTP. However, I’m struggling to find any way to set the position and duration of the current song. It seems like the only way to get what I want is to have librespot play the music and to use Kodi as a dummy player which just displays the song data including the position and duration. Is what I want at all possible?