How to record internal audio on Android devices or record MediaPlayer Audio Stream?

I'm currently trying to record an audio stream which is played in MediaPlayer.

Actually I found some blog-post, saying it's not possible because of security / copyright reasons, but I couldn't find any official statements from Android/Google docs. Furthermore, there are screen capture apps like Mobizen which can record internal audio (at least Samsung devices seems to work).

So can someone tell, if

1. internal audio is officially not allowed / supported?
2. it's possible to record a stream with AudioRecorder which is played in MediaPlayer?

I'm not so sure if I'm entering the dark side at the moment?

What I already tried to answer the 2nd question:

• recorded different MediaRecorder.AudioSource, but all record the microphone
• found byte by byte for recording, but this is not working with MediaPlayer

from How to record internal audio on Android devices or record MediaPlayer Audio Stream?