Unity3D + Andoird Camera as background

Hi everybody!
I’ve tried to find answer in this forum, but I found many connected questions without answers…
What is the fastest (best performance) way to show video-stream from camera as background? Especially in context, that I want to get this stream in C++ plugin for processing (computer vision)!

At first, I’m absolutely newby in Unity3d =)

In current moment I found few theoretical ways to do it:

  1. WebCameraTexture (I don’t care about drawing, access to frame data throught GetPixels)
  2. Write C++ plugin, use JNI notation inside plugin to create Camera java object and get frames. Then pull frame data to Unity side, or draw textured quad by openGL? It is possible?
  3. Use JNI Unity helpers

Can somebody give recommendation or suggestion to me about this ideas? I would be very glad if someone can share his experience or show worked sample!

Guys, come on!
Please help me! I think question is famous, and I’ll share result code for open-use.