Thanks for the info, gmpreussner!
But that’s a bit sad news for now. I’ve tested it also with the Unity engine and their MovieTexture is also not implemented for WebGL yet, but they have a workaround which works and I’ve made a Video Player with it with a html5 build. However, this workaround is not future save and Unity is not Unreal. So now I am a bit loss with planing my project further…
Anyhow, thanks again for your reply and thanks to all of the staff for the hard work and the fantastic Unreal Engine.
Greets