Record screen AND system sound on rooted device I cannot find a way that will allow me to capture and save both system video and audio (not microphone),  even on the Play Store. My device runs Android 6.0 Marshmallow and has root permissions access via SuperSU. I'm aware the API for system recording is not available in Stock Android, though I remember several apps being able to access internal audio for purposes such as streaming, casting, etc...
I recommend AZ Screen Recorder, it is free, lagless, quality video, sound available from system and from microphone. Most important feature is that root isn't required and it is completely free for the most important features.