Android Stagefright architecture

Stagefright is the core of android media playback framework. The class diagram below gives you high-level overview of its architecture.  The diagram can be dissembled to three groups, each answering one of the following questions:

  1. What consist of Stagefright? 
  2. How OpenMAX components can be plugged into Stagefright? 
  3. How the software encoder can be plugged into Stagefright?