Hi,
I'm having one of those black-screen problems with the Unity video sample when running on a Samsung Galaxy S2.
I'm using the videoplayback-3-0-10 Unity package/sample in Unity 4.6.1, on a Samsung GT-I9100 running Android version 4.0.4.
The sample works fine on iOS devices & on a Samsung Galaxy S5. I've also tried some of the suggested solutions to common black-screen problems without any luck.
I can't see anything in Logcat that hints at a problem either.
Has anyone else experienced this issue?
In the meantime, we have tested the VideoPlayback sample built from the Unity videoplayback sample unitypackage (Vuforia 3.0.9) on the Samsung Galaxy S2 and it worked fine. We could not reproduce the issue on our end.