Hello Polemos,
Before directing you to our official documentation for the Media Player Asset, it needs to be noted that this feature is still considered experimental and is not yet production ready. That being said, basing deadlines and major parts of your game or project around this feature since it is still in development will yield undesired results.
Media Player Asset
This documentation will show you how to use ‘Casting’ in order to get your Media Player and Media Sound Wave to play. I have been personally troubleshooting getting the Media Sound Wave to play in conjunction with an associated Media Player, and as you have noticed, does not work consistently if at all. I can usually get it to play once, but my video is also five and a half minutes long so it sometimes hitches prior to playing the video.
If you would like, I can show you how I have my scene set up if the ‘Casting’ approach does not work as desired. Let me know if you have any other questions or have additional comments.
Regards,