cameraViewRender and pipViewRender

Question

In the AntMedia Android Sdk documentation https://github.com/ant-media/Ant-Media-Server/wiki/WebRTC-Android-SDK-Documentation, there is the following code. What are cameraViewRender and pipViewRender? Why are there these two Views?

    SurfaceViewRenderer cameraViewRenderer = findViewById(R.id.camera_view_renderer);

    SurfaceViewRenderer pipViewRenderer = findViewById(R.id.pip_view_renderer);

    webRTCClient.setVideoRenderers(pipViewRenderer, cameraViewRenderer);