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+).
Finally it was a network problem, I was connecting my devices through a MacBook WiFi sharing, and it seems that it blocked the RTSP stream. Now I am using a router and it works in RTSP (I'm still not able to receive a HTTP stream in the Android VideoView). Nevertheless, I still have a timeout issue : the RTSP stream stops after 60 sec, because the VideoView doesn't send keep alive messages. I will try to do it myself...