For my app I have to stream from a decklink card to an Android app (I must be a live stream, so either HLS or RTSP seems to be good solutions, since my app targets Android 3+).
Use MediaPlayer it supports both HTTP and RTSP network protocols.
http://developer.android.com/guide/topics/media/mediaplayer.html#mediaplayer
http://developer.android.com/guide/appendix/media-formats.html#recommendations