Stream Live Video from Android to RTMP Server

I'm working on an Android RAT (Remote Administration Tool) project as a course project. I want to add live video stream feature to the RAT. I've searched for different ways and find out three different ways:

1. Captures video from service, then upload the video


2. Streams video from camera in a local web server inside Android application (such as https://github.com/darshanrn/SpyCam)


3. Ant Media which is exactly the suitable solution which encodes the video and transfer as a live stream (https://github.com/ant-media/LiveVideoBroadcaster)

But the problem is that Ant Broadcaster needs an activity to preview the camera, however as it is described HERE (https://github.com/sprimgupta/Secret-Video-Recorder) it is possible to record video from a service without previewing.

I wonder how to make video stream inside service using Ant Broadcaster?

Ant Media connects a service to an activity and then broadcast the video:
https://github.com/ant-media/LiveVideoBroadcaster/blob/master/liveVideoBroadcasterSDK/src/main/java/io/antmedia/android/broadcaster/LiveVideoBroadcaster.java