I have my Unity App set to play a video when Vuforia detects an image.
It works great other than the first time Vuforia detects the image I see the white quad displayed while the video is loading.
It's only a split second but it really does kill the user experience. I don't mind the delay it's really just seeing the white square that bugs me.
So, I suppose there are a few options....
1) Preload the video, this could be an issue as I have 30 different videos to play based on images in a book.
2) Make the quad transparent until the video is loaded.
I have no idea how to do either :-)